GitHub/MotorolaMobilityLLC/kernel-slsi.git
7 years agoradix-tree: improve multiorder iterators
Matthew Wilcox [Wed, 14 Dec 2016 23:08:49 +0000 (15:08 -0800)]
radix-tree: improve multiorder iterators

This fixes several interlinked problems with the iterators in the
presence of multiorder entries.

1. radix_tree_iter_next() would only advance by one slot, which would
   result in the iterators returning the same entry more than once if
   there were sibling entries.

2. radix_tree_next_slot() could return an internal pointer instead of
   a user pointer if a tagged multiorder entry was immediately followed by
   an entry of lower order.

3. radix_tree_next_slot() expanded to a lot more code than it used to
   when multiorder support was compiled in.  And I wasn't comfortable with
   entry_to_node() being in a header file.

Fixing radix_tree_iter_next() for the presence of sibling entries
necessarily involves examining the contents of the radix tree, so we now
need to pass 'slot' to radix_tree_iter_next(), and we need to change the
calling convention so it is called *before* dropping the lock which
protects the tree.  Also rename it to radix_tree_iter_resume(), as some
people thought it was necessary to call radix_tree_iter_next() each time
around the loop.

radix_tree_next_slot() becomes closer to how it looked before multiorder
support was introduced.  It only checks to see if the next entry in the
chunk is a sibling entry or a pointer to a node; this should be rare
enough that handling this case out of line is not a performance impact
(and such impact is amortised by the fact that the entry we just
processed was a multiorder entry).  Also, radix_tree_next_slot() used to
force a new chunk lookup for untagged entries, which is more expensive
than the out of line sibling entry skipping.

Link: http://lkml.kernel.org/r/1480369871-5271-55-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agobtrfs: fix race in btrfs_free_dummy_fs_info()
Matthew Wilcox [Wed, 14 Dec 2016 23:08:46 +0000 (15:08 -0800)]
btrfs: fix race in btrfs_free_dummy_fs_info()

We drop the lock which protects the radix tree, so we must call
radix_tree_iter_next() in order to avoid a modification to the tree
invalidating the iterator state.

Link: http://lkml.kernel.org/r/1480369871-5271-54-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix-tree: improve dump output
Matthew Wilcox [Wed, 14 Dec 2016 23:08:43 +0000 (15:08 -0800)]
radix-tree: improve dump output

Print the indices of the entries as unsigned (instead of signed)
integers and print the parent node of each entry to help navigate around
larger trees where the layout is not quite so obvious.  Print the
indices covered by a node.  Rearrange the order of fields printed so the
indices and parents line up for each type of entry.

Link: http://lkml.kernel.org/r/1480369871-5271-53-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix-tree: make radix_tree_find_next_bit more useful
Matthew Wilcox [Wed, 14 Dec 2016 23:08:40 +0000 (15:08 -0800)]
radix-tree: make radix_tree_find_next_bit more useful

Since this function is specialised to the radix tree, pass in the node
and tag to calculate the address of the bitmap in
radix_tree_find_next_bit() instead of the caller.  Likewise, there is no
need to pass in the size of the bitmap.

Link: http://lkml.kernel.org/r/1480369871-5271-52-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix-tree: create node_tag_set()
Matthew Wilcox [Wed, 14 Dec 2016 23:08:37 +0000 (15:08 -0800)]
radix-tree: create node_tag_set()

Similar to node_tag_clear(), factor node_tag_set() out of
radix_tree_range_tag_if_tagged().

Link: http://lkml.kernel.org/r/1480369871-5271-51-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix-tree: move rcu_head into a union with private_list
Matthew Wilcox [Wed, 14 Dec 2016 23:08:34 +0000 (15:08 -0800)]
radix-tree: move rcu_head into a union with private_list

I want to be able to reference node->parent after freeing node.

Currently node->parent is in a union with rcu_head, so it is overwritten
when the node is put on the RCU list.  We know that private_list is not
referenced after the node is freed, so it is safe for these two members
to share space.

Link: http://lkml.kernel.org/r/1480369871-5271-50-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix-tree: fix typo
Matthew Wilcox [Wed, 14 Dec 2016 23:08:31 +0000 (15:08 -0800)]
radix-tree: fix typo

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: use common find-bit code
Matthew Wilcox [Wed, 14 Dec 2016 23:08:29 +0000 (15:08 -0800)]
radix tree test suite: use common find-bit code

Remove the old find_next_bit code in favour of linking in the find_bit
code from tools/lib.

Link: http://lkml.kernel.org/r/1480369871-5271-48-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agotools: add more bitmap functions
Matthew Wilcox [Wed, 14 Dec 2016 23:08:26 +0000 (15:08 -0800)]
tools: add more bitmap functions

I need the following functions for the radix tree:

  bitmap_fill
  bitmap_empty
  bitmap_full

Copy the implementations from include/linux/bitmap.h

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: record order in each item
Matthew Wilcox [Wed, 14 Dec 2016 23:08:23 +0000 (15:08 -0800)]
radix tree test suite: record order in each item

This probably doubles the size of each item allocated by the test suite
but it lets us check a few more things, and may be needed for upcoming
API changes that require the caller pass in the order of the entry.

Link: http://lkml.kernel.org/r/1480369871-5271-46-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: handle exceptional entries
Matthew Wilcox [Wed, 14 Dec 2016 23:08:20 +0000 (15:08 -0800)]
radix tree test suite: handle exceptional entries

item_kill_tree() assumes that everything in the tree is a pointer to a
struct item, which is annoying when testing the behaviour of exceptional
entries.  Fix it to delete exceptional entries on the assumption they
don't need to be freed.

Link: http://lkml.kernel.org/r/1480369871-5271-45-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: use rcu_barrier
Matthew Wilcox [Wed, 14 Dec 2016 23:08:17 +0000 (15:08 -0800)]
radix tree test suite: use rcu_barrier

Calling rcu_barrier() allows all of the rcu-freed memory to be actually
returned to the pool, and allows nr_allocated to return to 0.  As well
as allowing diffs between runs to be more useful, it also lets us
pinpoint leaks more effectively.

Link: http://lkml.kernel.org/r/1480369871-5271-44-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: benchmark for iterator
Konstantin Khlebnikov [Wed, 14 Dec 2016 23:08:14 +0000 (15:08 -0800)]
radix tree test suite: benchmark for iterator

This adds simple benchmark for iterator similar to one I've used for
commit 78c1d78488a3 ("radix-tree: introduce bit-optimized iterator")

Building with make BENCHMARK=1 set radix tree order to 6, this allows to
get performance comparable to in kernel performance.

Link: http://lkml.kernel.org/r/1480369871-5271-43-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: iteration test misuses RCU
Matthew Wilcox [Wed, 14 Dec 2016 23:08:11 +0000 (15:08 -0800)]
radix tree test suite: iteration test misuses RCU

Each thread needs to register itself with RCU, otherwise the reading
thread's read lock has no effect and the freeing thread will free the
memory in the tree without waiting for the read lock to be dropped.

Link: http://lkml.kernel.org/r/1480369871-5271-42-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: make runs more reproducible
Matthew Wilcox [Wed, 14 Dec 2016 23:08:08 +0000 (15:08 -0800)]
radix tree test suite: make runs more reproducible

Instead of reseeding the random number generator every time around the
loop in big_gang_check(), seed it at the beginning of execution.  Use
rand_r() and an independent base seed for each thread in
iteration_test() so they don't stomp all over each others state.  Since
this particular test depends on the kernel scheduler, the iteration test
can't be reproduced based purely on the random seed, but at least it
won't pollute the other tests.

Print the seed, and allow the seed to be specified so that a run which
hits a problem can be reproduced.

Link: http://lkml.kernel.org/r/1480369871-5271-41-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: free preallocated nodes
Matthew Wilcox [Wed, 14 Dec 2016 23:08:05 +0000 (15:08 -0800)]
radix tree test suite: free preallocated nodes

It can be a source of mild concern when the test suite shows that we're
leaking nodes.  While poring over the source code looking for leaks can
lead to some fascinating bugs being discovered, sometimes the leak is
simply that these nodes were preallocated and are sitting on the per-CPU
list.  Free them by calling the CPU dead callback.

Link: http://lkml.kernel.org/r/1480369871-5271-40-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: track preempt_count
Matthew Wilcox [Wed, 14 Dec 2016 23:08:02 +0000 (15:08 -0800)]
radix tree test suite: track preempt_count

Rather than simply NOP out preempt_enable() and preempt_disable(), keep
track of preempt_count and display it regularly in case either the test
suite or the code under test is forgetting to balance the enables &
disables.  Only found a test-case that was forgetting to re-enable
preemption, but it's a possibility worth checking.

Link: http://lkml.kernel.org/r/1480369871-5271-39-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoradix tree test suite: allow GFP_ATOMIC allocations to fail
Matthew Wilcox [Wed, 14 Dec 2016 23:07:59 +0000 (15:07 -0800)]
radix tree test suite: allow GFP_ATOMIC allocations to fail

In order to test the preload code, it is necessary to fail GFP_ATOMIC
allocations, which requires defining GFP_KERNEL and GFP_ATOMIC properly.
Remove the obsolete __GFP_WAIT and copy the definitions of the __GFP
flags which are used from the kernel include files.  We also need the
real definition of gfpflags_allow_blocking() to persuade the radix tree
to actually use its preallocated nodes.

Link: http://lkml.kernel.org/r/1480369871-5271-38-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agotools: add WARN_ON_ONCE
Matthew Wilcox [Wed, 14 Dec 2016 23:07:56 +0000 (15:07 -0800)]
tools: add WARN_ON_ONCE

Patch series "Radix tree patches for 4.10", v3.

Mostly these are improvements; the only bug fixes in here relate to
multiorder entries (which are unused in the 4.9 tree).

This patch (of 32):

The radix tree uses its own buggy WARN_ON_ONCE.  Replace it with the
definition from asm-generic/bug.h

Link: http://lkml.kernel.org/r/1480369871-5271-37-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agodax: clear dirty entry tags on cache flush
Jan Kara [Wed, 14 Dec 2016 23:07:53 +0000 (15:07 -0800)]
dax: clear dirty entry tags on cache flush

Currently we never clear dirty tags in DAX mappings and thus address
ranges to flush accumulate.  Now that we have locking of radix tree
entries, we have all the locking necessary to reliably clear the radix
tree dirty tag when flushing caches for corresponding address range.
Similarly to page_mkclean() we also have to write-protect pages to get a
page fault when the page is next written to so that we can mark the
entry dirty again.

Link: http://lkml.kernel.org/r/1479460644-25076-21-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agodax: protect PTE modification on WP fault by radix tree entry lock
Jan Kara [Wed, 14 Dec 2016 23:07:50 +0000 (15:07 -0800)]
dax: protect PTE modification on WP fault by radix tree entry lock

Currently PTE gets updated in wp_pfn_shared() after dax_pfn_mkwrite()
has released corresponding radix tree entry lock.  When we want to
writeprotect PTE on cache flush, we need PTE modification to happen
under radix tree entry lock to ensure consistent updates of PTE and
radix tree (standard faults use page lock to ensure this consistency).
So move update of PTE bit into dax_pfn_mkwrite().

Link: http://lkml.kernel.org/r/1479460644-25076-20-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agodax: make cache flushing protected by entry lock
Jan Kara [Wed, 14 Dec 2016 23:07:47 +0000 (15:07 -0800)]
dax: make cache flushing protected by entry lock

Currently, flushing of caches for DAX mappings was ignoring entry lock.
So far this was ok (modulo a bug that a difference in entry lock could
cause cache flushing to be mistakenly skipped) but in the following
patches we will write-protect PTEs on cache flushing and clear dirty
tags.  For that we will need more exclusion.  So do cache flushing under
an entry lock.  This allows us to remove one lock-unlock pair of
mapping->tree_lock as a bonus.

Link: http://lkml.kernel.org/r/1479460644-25076-19-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: export follow_pte()
Jan Kara [Wed, 14 Dec 2016 23:07:45 +0000 (15:07 -0800)]
mm: export follow_pte()

DAX will need to implement its own version of page_check_address().  To
avoid duplicating page table walking code, export follow_pte() which
does what we need.

Link: http://lkml.kernel.org/r/1479460644-25076-18-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: change return values of finish_mkwrite_fault()
Jan Kara [Wed, 14 Dec 2016 23:07:42 +0000 (15:07 -0800)]
mm: change return values of finish_mkwrite_fault()

Currently finish_mkwrite_fault() returns 0 when PTE got changed before
we acquired PTE lock and VM_FAULT_WRITE when we succeeded in modifying
the PTE.  This is somewhat confusing since 0 generally means success, it
is also inconsistent with finish_fault() which returns 0 on success.
Change finish_mkwrite_fault() to return 0 on success and VM_FAULT_NOPAGE
when PTE changed.  Practically, there should be no behavioral difference
since we bail out from the fault the same way regardless whether we
return 0, VM_FAULT_NOPAGE, or VM_FAULT_WRITE.  Also note that
VM_FAULT_WRITE has no effect for shared mappings since the only two
places that check it - KSM and GUP - care about private mappings only.
Generally the meaning of VM_FAULT_WRITE for shared mappings is not well
defined and we should probably clean that up.

Link: http://lkml.kernel.org/r/1479460644-25076-17-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: provide helper for finishing mkwrite faults
Jan Kara [Wed, 14 Dec 2016 23:07:39 +0000 (15:07 -0800)]
mm: provide helper for finishing mkwrite faults

Provide a helper function for finishing write faults due to PTE being
read-only.  The helper will be used by DAX to avoid the need of
complicating generic MM code with DAX locking specifics.

Link: http://lkml.kernel.org/r/1479460644-25076-16-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: move part of wp_page_reuse() into the single call site
Jan Kara [Wed, 14 Dec 2016 23:07:36 +0000 (15:07 -0800)]
mm: move part of wp_page_reuse() into the single call site

wp_page_reuse() handles write shared faults which is needed only in
wp_page_shared().  Move the handling only into that location to make
wp_page_reuse() simpler and avoid a strange situation when we sometimes
pass in locked page, sometimes unlocked etc.

Link: http://lkml.kernel.org/r/1479460644-25076-15-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: use vmf->page during WP faults
Jan Kara [Wed, 14 Dec 2016 23:07:33 +0000 (15:07 -0800)]
mm: use vmf->page during WP faults

So far we set vmf->page during WP faults only when we needed to pass it
to the ->page_mkwrite handler.  Set it in all the cases now and use that
instead of passing page pointer explicitly around.

Link: http://lkml.kernel.org/r/1479460644-25076-14-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: pass vm_fault structure into do_page_mkwrite()
Jan Kara [Wed, 14 Dec 2016 23:07:30 +0000 (15:07 -0800)]
mm: pass vm_fault structure into do_page_mkwrite()

We will need more information in the ->page_mkwrite() helper for DAX to
be able to fully finish faults there.  Pass vm_fault structure to
do_page_mkwrite() and use it there so that information propagates
properly from upper layers.

Link: http://lkml.kernel.org/r/1479460644-25076-13-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: factor out common parts of write fault handling
Jan Kara [Wed, 14 Dec 2016 23:07:27 +0000 (15:07 -0800)]
mm: factor out common parts of write fault handling

Currently we duplicate handling of shared write faults in
wp_page_reuse() and do_shared_fault().  Factor them out into a common
function.

Link: http://lkml.kernel.org/r/1479460644-25076-12-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: move handling of COW faults into DAX code
Jan Kara [Wed, 14 Dec 2016 23:07:24 +0000 (15:07 -0800)]
mm: move handling of COW faults into DAX code

Move final handling of COW faults from generic code into DAX fault
handler.  That way generic code doesn't have to be aware of
peculiarities of DAX locking so remove that knowledge and make locking
functions private to fs/dax.c.

Link: http://lkml.kernel.org/r/1479460644-25076-11-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: factor out functionality to finish page faults
Jan Kara [Wed, 14 Dec 2016 23:07:21 +0000 (15:07 -0800)]
mm: factor out functionality to finish page faults

Introduce finish_fault() as a helper function for finishing page faults.
It is rather thin wrapper around alloc_set_pte() but since we'd want to
call this from DAX code or filesystems, it is still useful to avoid some
boilerplate code.

Link: http://lkml.kernel.org/r/1479460644-25076-10-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: allow full handling of COW faults in ->fault handlers
Jan Kara [Wed, 14 Dec 2016 23:07:18 +0000 (15:07 -0800)]
mm: allow full handling of COW faults in ->fault handlers

Patch series "dax: Clear dirty bits after flushing caches", v5.

Patchset to clear dirty bits from radix tree of DAX inodes when caches
for corresponding pfns have been flushed.  In principle, these patches
enable handlers to easily update PTEs and do other work necessary to
finish the fault without duplicating the functionality present in the
generic code.  I'd like to thank Kirill and Ross for reviews of the
series!

This patch (of 20):

To allow full handling of COW faults add memcg field to struct vm_fault
and a return value of ->fault() handler meaning that COW fault is fully
handled and memcg charge must not be canceled.  This will allow us to
remove knowledge about special DAX locking from the generic fault code.

Link: http://lkml.kernel.org/r/1479460644-25076-9-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: add orig_pte field into vm_fault
Jan Kara [Wed, 14 Dec 2016 23:07:16 +0000 (15:07 -0800)]
mm: add orig_pte field into vm_fault

Add orig_pte field to vm_fault structure to allow ->page_mkwrite
handlers to fully handle the fault.

This also allows us to save some passing of extra arguments around.

Link: http://lkml.kernel.org/r/1479460644-25076-8-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: use passed vm_fault structure for in wp_pfn_shared()
Jan Kara [Wed, 14 Dec 2016 23:07:13 +0000 (15:07 -0800)]
mm: use passed vm_fault structure for in wp_pfn_shared()

Instead of creating another vm_fault structure, use the one passed to
wp_pfn_shared() for passing arguments into pfn_mkwrite handler.

Link: http://lkml.kernel.org/r/1479460644-25076-7-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: trim __do_fault() arguments
Jan Kara [Wed, 14 Dec 2016 23:07:10 +0000 (15:07 -0800)]
mm: trim __do_fault() arguments

Use vm_fault structure to pass cow_page, page, and entry in and out of
the function.

That reduces number of __do_fault() arguments from 4 to 1.

Link: http://lkml.kernel.org/r/1479460644-25076-6-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: use passed vm_fault structure in __do_fault()
Jan Kara [Wed, 14 Dec 2016 23:07:07 +0000 (15:07 -0800)]
mm: use passed vm_fault structure in __do_fault()

Instead of creating another vm_fault structure, use the one passed to
__do_fault() for passing arguments into fault handler.

Link: http://lkml.kernel.org/r/1479460644-25076-5-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: use pgoff in struct vm_fault instead of passing it separately
Jan Kara [Wed, 14 Dec 2016 23:07:04 +0000 (15:07 -0800)]
mm: use pgoff in struct vm_fault instead of passing it separately

struct vm_fault has already pgoff entry.  Use it instead of passing
pgoff as a separate argument and then assigning it later.

Link: http://lkml.kernel.org/r/1479460644-25076-4-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: use vmf->address instead of of vmf->virtual_address
Jan Kara [Wed, 14 Dec 2016 23:07:01 +0000 (15:07 -0800)]
mm: use vmf->address instead of of vmf->virtual_address

Every single user of vmf->virtual_address typed that entry to unsigned
long before doing anything with it so the type of virtual_address does
not really provide us any additional safety.  Just use masked
vmf->address which already has the appropriate type.

Link: http://lkml.kernel.org/r/1479460644-25076-3-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: join struct fault_env and vm_fault
Jan Kara [Wed, 14 Dec 2016 23:06:58 +0000 (15:06 -0800)]
mm: join struct fault_env and vm_fault

Currently we have two different structures for passing fault information
around - struct vm_fault and struct fault_env.  DAX will need more
information in struct vm_fault to handle its faults so the content of
that structure would become event closer to fault_env.  Furthermore it
would need to generate struct fault_env to be able to call some of the
generic functions.  So at this point I don't think there's much use in
keeping these two structures separate.  Just embed into struct vm_fault
all that is needed to use it for both purposes.

Link: http://lkml.kernel.org/r/1479460644-25076-2-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: unexport __get_user_pages_unlocked()
Lorenzo Stoakes [Wed, 14 Dec 2016 23:06:55 +0000 (15:06 -0800)]
mm: unexport __get_user_pages_unlocked()

Unexport the low-level __get_user_pages_unlocked() function and replaces
invocations with calls to more appropriate higher-level functions.

In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked()
with get_user_pages_unlocked() since we can now pass gup_flags.

In async_pf_execute() and process_vm_rw_single_vec() we need to pass
different tsk, mm arguments so get_user_pages_remote() is the sane
replacement in these cases (having added manual acquisition and release
of mmap_sem.)

Additionally get_user_pages_remote() reintroduces use of the FOLL_TOUCH
flag.  However, this flag was originally silently dropped by commit
1e9877902dc7 ("mm/gup: Introduce get_user_pages_remote()"), so this
appears to have been unintentional and reintroducing it is therefore not
an issue.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20161027095141.2569-3-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: add locked parameter to get_user_pages_remote()
Lorenzo Stoakes [Wed, 14 Dec 2016 23:06:52 +0000 (15:06 -0800)]
mm: add locked parameter to get_user_pages_remote()

Patch series "mm: unexport __get_user_pages_unlocked()".

This patch series continues the cleanup of get_user_pages*() functions
taking advantage of the fact we can now pass gup_flags as we please.

It firstly adds an additional 'locked' parameter to
get_user_pages_remote() to allow for its callers to utilise
VM_FAULT_RETRY functionality.  This is necessary as the invocation of
__get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of
this and no other existing higher level function would allow it to do
so.

Secondly existing callers of __get_user_pages_unlocked() are replaced
with the appropriate higher-level replacement -
get_user_pages_unlocked() if the current task and memory descriptor are
referenced, or get_user_pages_remote() if other task/memory descriptors
are referenced (having acquiring mmap_sem.)

This patch (of 2):

Add a int *locked parameter to get_user_pages_remote() to allow
VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked().

Taking into account the previous adjustments to get_user_pages*()
functions allowing for the passing of gup_flags, we are now in a
position where __get_user_pages_unlocked() need only be exported for his
ability to allow VM_FAULT_RETRY behaviour, this adjustment allows us to
subsequently unexport __get_user_pages_unlocked() as well as allowing
for future flexibility in the use of get_user_pages_remote().

[sfr@canb.auug.org.au: merge fix for get_user_pages_remote API change]
Link: http://lkml.kernel.org/r/20161122210511.024ec341@canb.auug.org.au
Link: http://lkml.kernel.org/r/20161027095141.2569-2-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/sem: avoid idr tree lookup for interrupted semop
Davidlohr Bueso [Wed, 14 Dec 2016 23:06:49 +0000 (15:06 -0800)]
ipc/sem: avoid idr tree lookup for interrupted semop

We can avoid the idr tree lookup (albeit possibly avoiding
idr_find_fast()) when being awoken in EINTR, as the semid will not
change in this context while blocked.  Use the sma pointer directly and
take the sem_lock, then re-check for RMID races.  We continue to
re-check the queue.status with the lock held such that we can detect
situations where we where are dealing with a spurious wakeup but another
task that holds the sem_lock updated the queue.status while we were
spinning for it.  Once we take the lock it obviously won't change again.

Being the only caller, get rid of sem_obtain_lock() altogether.

Link: http://lkml.kernel.org/r/1478708774-28826-3-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/sem: simplify wait-wake loop
Davidlohr Bueso [Wed, 14 Dec 2016 23:06:46 +0000 (15:06 -0800)]
ipc/sem: simplify wait-wake loop

Instead of using the reverse goto, we can simplify the flow and make it
more language natural by just doing do-while instead.  One would hope
this is the standard way (or obviously just with a while bucle) that we
do wait/wakeup handling in the kernel.  The exact same logic is kept,
just more indented.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1478708774-28826-2-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/sem: use proper list api for pending_list wakeups
Davidlohr Bueso [Wed, 14 Dec 2016 23:06:43 +0000 (15:06 -0800)]
ipc/sem: use proper list api for pending_list wakeups

... saves some LoC and looks cleaner than re-implementing the calls.

Link: http://lkml.kernel.org/r/1474225896-10066-6-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/sem: explicitly inline check_restart
Davidlohr Bueso [Wed, 14 Dec 2016 23:06:40 +0000 (15:06 -0800)]
ipc/sem: explicitly inline check_restart

The compiler already does this, but make it explicit.  This helper is
really small and also used in update_queue's main loop, which is O(N^2)
scanning.  Inline and avoid the function overhead.

Link: http://lkml.kernel.org/r/1474225896-10066-5-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/sem: optimize perform_atomic_semop()
Davidlohr Bueso [Wed, 14 Dec 2016 23:06:37 +0000 (15:06 -0800)]
ipc/sem: optimize perform_atomic_semop()

This is the main workhorse that deals with semop user calls such that
the waitforzero or semval update operations, on the set, can complete on
not as the sma currently stands.  Currently, the set is iterated twice
(setting semval, then backwards for the sempid value).  Slowpaths, and
particularly SEM_UNDO calls, must undo any altered sem when it is
detected that the caller must block or has errored-out.

With larger sets, there can occur situations where this involves a lot
of cycles and can obviously be a suboptimal use of cached resources in
shared memory.  Ie, discarding CPU caches that are also calling semop
and have the sembuf cached (and can complete), while the current lock
holder doing the semop will block, error, or does a waitforzero
operation.

This patch proposes still iterating the set twice, but the first scan is
read-only, and we perform the actual updates afterward, once we know
that the call will succeed.  In order to not suffer from the overhead of
dealing with sops that act on the same sem_num, such (rare) cases use
perform_atomic_semop_slow(), which is exactly what we have now.
Duplicates are detected before grabbing sem_lock, and uses simple a
32/64-bit hash array variable to based on the sem_num we are working on.

In addition add some comments to when we expect to the caller to block.

[akpm@linux-foundation.org: coding-style fixes]
[colin.king@canonical.com: ensure we left shift a ULL rather than a 32 bit integer]
Link: http://lkml.kernel.org/r/20161028181129.7311-1-colin.king@canonical.com
Link: http://lkml.kernel.org/r/20160921194603.GB21438@linux-80c1.suse
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/sem: rework task wakeups
Davidlohr Bueso [Wed, 14 Dec 2016 23:06:34 +0000 (15:06 -0800)]
ipc/sem: rework task wakeups

Our sysv sems have been using the notion of lockless wakeups for a
while, ever since commit 0a2b9d4c7967 ("ipc/sem.c: move wake_up_process
out of the spinlock section"), in order to reduce the sem_lock hold
times.  This in-house pending queue can be replaced by wake_q (just like
all the rest of ipc now), in that it provides the following advantages:

 o Simplifies and gets rid of unnecessary code.

 o We get rid of the IN_WAKEUP complexities. Given that wake_q_add()
   grabs reference to the task, if awoken due to an unrelated event,
   between the wake_q_add() and wake_up_q() window, we cannot race with
   sys_exit and the imminent call to wake_up_process().

 o By not spinning IN_WAKEUP, we no longer need to disable preemption.

In consequence, the wakeup paths (after schedule(), that is) must
acknowledge an external signal/event, as well spurious wakeup occurring
during the pending wakeup window.  Obviously no changes in semantics
that could be visible to the user.  The fastpath is _only_ for when we
know for sure that we were awoken due to a the waker's successful semop
call (queue.status is not -EINTR).

On a 48-core Haswell, running the ipcscale 'waitforzero' test, the
following is seen with increasing thread counts:

                               v4.8-rc5                v4.8-rc5
                                                        semopv2
Hmean    sembench-sem-2      574733.00 (  0.00%)   578322.00 (  0.62%)
Hmean    sembench-sem-8      811708.00 (  0.00%)   824689.00 (  1.59%)
Hmean    sembench-sem-12     842448.00 (  0.00%)   845409.00 (  0.35%)
Hmean    sembench-sem-21     933003.00 (  0.00%)   977748.00 (  4.80%)
Hmean    sembench-sem-48     935910.00 (  0.00%)  1004759.00 (  7.36%)
Hmean    sembench-sem-79     937186.00 (  0.00%)   983976.00 (  4.99%)
Hmean    sembench-sem-234    974256.00 (  0.00%)  1060294.00 (  8.83%)
Hmean    sembench-sem-265    975468.00 (  0.00%)  1016243.00 (  4.18%)
Hmean    sembench-sem-296    991280.00 (  0.00%)  1042659.00 (  5.18%)
Hmean    sembench-sem-327    975415.00 (  0.00%)  1029977.00 (  5.59%)
Hmean    sembench-sem-358   1014286.00 (  0.00%)  1049624.00 (  3.48%)
Hmean    sembench-sem-389    972939.00 (  0.00%)  1043127.00 (  7.21%)
Hmean    sembench-sem-420    981909.00 (  0.00%)  1056747.00 (  7.62%)
Hmean    sembench-sem-451    990139.00 (  0.00%)  1051609.00 (  6.21%)
Hmean    sembench-sem-482    965735.00 (  0.00%)  1040313.00 (  7.72%)

[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: merge fix for WAKE_Q to DEFINE_WAKE_Q rename]
Link: http://lkml.kernel.org/r/20161122210410.5eca9fc2@canb.auug.org.au
Link: http://lkml.kernel.org/r/1474225896-10066-3-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/sem: do not call wake_sem_queue_do() prematurely ... as this call should obviousl...
Davidlohr Bueso [Wed, 14 Dec 2016 23:06:31 +0000 (15:06 -0800)]
ipc/sem: do not call wake_sem_queue_do() prematurely ... as this call should obviously be paired with its _prepare()

counterpart.  At least whenever possible, as there is no harm in calling
it bogusly as we do now in a few places.  Immediate error semop(2) paths
that are far from ever having the task block can be simplified and avoid
a few unnecessary loads on their way out of the call as it is not deeply
nested.

Link: http://lkml.kernel.org/r/1474225896-10066-2-git-send-email-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agosparc: implement watchdog_nmi_enable and watchdog_nmi_disable
Babu Moger [Wed, 14 Dec 2016 23:06:28 +0000 (15:06 -0800)]
sparc: implement watchdog_nmi_enable and watchdog_nmi_disable

Implement functions watchdog_nmi_enable and watchdog_nmi_disable to
enable/disable nmi watchdog.  Sparc uses arch specific nmi watchdog
handler.  Currently, we do not have a way to enable/disable nmi watchdog
dynamically.  With these patches we can enable or disable arch specific
nmi watchdogs using proc or sysctl interface.

Example commands.
To enable: echo 1 >  /proc/sys/kernel/nmi_watchdog
To disable: echo 0 >  /proc/sys/kernel/nmi_watchdog

It can also achieved using the sysctl parameter kernel.nmi_watchdog

Link: http://lkml.kernel.org/r/1478034826-43888-4-git-send-email-babu.moger@oracle.com
Signed-off-by: Babu Moger <babu.moger@oracle.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Josh Hunt <johunt@akamai.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokernel/watchdog.c: move hardlockup detector to separate file
Babu Moger [Wed, 14 Dec 2016 23:06:24 +0000 (15:06 -0800)]
kernel/watchdog.c: move hardlockup detector to separate file

Separate hardlockup code from watchdog.c and move it to watchdog_hld.c.
It is mostly straight forward.  Remove everything inside
CONFIG_HARDLOCKUP_DETECTORS.  This code will go to file watchdog_hld.c.
Also update the makefile accordigly.

Link: http://lkml.kernel.org/r/1478034826-43888-3-git-send-email-babu.moger@oracle.com
Signed-off-by: Babu Moger <babu.moger@oracle.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Josh Hunt <johunt@akamai.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokernel/watchdog.c: move shared definitions to nmi.h
Babu Moger [Wed, 14 Dec 2016 23:06:21 +0000 (15:06 -0800)]
kernel/watchdog.c: move shared definitions to nmi.h

Patch series "Clean up watchdog handlers", v2.

This is an attempt to cleanup watchdog handlers.  Right now,
kernel/watchdog.c implements both softlockup and hardlockup detectors.
Softlockup code is generic.  Hardlockup code is arch specific.  Some
architectures don't use hardlockup detectors.  They use their own
watchdog detectors.  To make both these combination work, we have
numerous #ifdefs in kernel/watchdog.c.

We are trying here to make these handlers independent of each other.
Also provide an interface for architectures to implement their own
handlers.  watchdog_nmi_enable and watchdog_nmi_disable will be defined
as weak such that architectures can override its definitions.

Thanks to Don Zickus for his suggestions.
Here are our previous discussions
http://www.spinics.net/lists/sparclinux/msg16543.html
http://www.spinics.net/lists/sparclinux/msg16441.html

This patch (of 3):

Move shared macros and definitions to nmi.h so that watchdog.c, new file
watchdog_hld.c or any other architecture specific handler can use those
definitions.

Link: http://lkml.kernel.org/r/1478034826-43888-2-git-send-email-babu.moger@oracle.com
Signed-off-by: Babu Moger <babu.moger@oracle.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Josh Hunt <johunt@akamai.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoktest.pl: fix english
Pavel Machek [Wed, 14 Dec 2016 23:06:18 +0000 (15:06 -0800)]
ktest.pl: fix english

Ajdust spelling to more common "mandatory".  Variant "mandidory" is
certainly wrong.

Link: http://lkml.kernel.org/r/20161011073003.GA19476@amd
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agodrivers/net/wireless/intel/iwlwifi/dvm/calib.c: simplfy min() expression
Andrew Morton [Wed, 14 Dec 2016 23:06:15 +0000 (15:06 -0800)]
drivers/net/wireless/intel/iwlwifi/dvm/calib.c: simplfy min() expression

This cast is no longer needed.

Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Cc: Intel Linux Wireless <linuxwifi@intel.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoposix-timers: give lazy compilers some help optimizing code away
Nicolas Pitre [Wed, 14 Dec 2016 23:06:13 +0000 (15:06 -0800)]
posix-timers: give lazy compilers some help optimizing code away

The OpenRISC compiler (so far) fails to optimize away a large portion of
code containing a reference to posix_timer_event in alarmtimer.c when
CONFIG_POSIX_TIMERS is unset.  Let's give it a direct clue to let the
build succeed.

This fixes
[linux-next:master 6682/7183] alarmtimer.c:undefined reference to `posix_timer_event'
reported by kbuild test robot.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc/shm.c: coding style fixes
Shailesh Pandey [Wed, 14 Dec 2016 23:06:10 +0000 (15:06 -0800)]
ipc/shm.c: coding style fixes

This patch fixes below warnings:

  WARNING: Missing a blank line after declarations
  WARNING: Block comments use a trailing */ on a separate line
  ERROR: spaces required around that '=' (ctx:WxV)

Above warnings were reported by checkpatch.pl

Link: http://lkml.kernel.org/r/1478604980-18062-1-git-send-email-p.shailesh@samsung.com
Signed-off-by: Shailesh Pandey <p.shailesh@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoipc: msg, make msgrcv work with LONG_MIN
Jiri Slaby [Wed, 14 Dec 2016 23:06:07 +0000 (15:06 -0800)]
ipc: msg, make msgrcv work with LONG_MIN

When LONG_MIN is passed to msgrcv, one would expect to recieve any
message.  But convert_mode does *msgtyp = -*msgtyp and -LONG_MIN is
undefined.  In particular, with my gcc -LONG_MIN produces -LONG_MIN
again.

So handle this case properly by assigning LONG_MAX to *msgtyp if
LONG_MIN was specified as msgtyp to msgrcv.

This code:
  long msg[] = { 100, 200 };
  int m = msgget(IPC_PRIVATE, IPC_CREAT | 0644);
  msgsnd(m, &msg, sizeof(msg), 0);
  msgrcv(m, &msg, sizeof(msg), LONG_MIN, 0);

produces currently nothing:

  msgget(IPC_PRIVATE, IPC_CREAT|0644)     = 65538
  msgsnd(65538, {100, "\310\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16, 0) = 0
  msgrcv(65538, ...

Except a UBSAN warning:

  UBSAN: Undefined behaviour in ipc/msg.c:745:13
  negation of -9223372036854775808 cannot be represented in type 'long int':

With the patch, I see what I expect:

  msgget(IPC_PRIVATE, IPC_CREAT|0644)     = 0
  msgsnd(0, {100, "\310\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16, 0) = 0
  msgrcv(0, {100, "\310\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16, -9223372036854775808, 0) = 16

Link: http://lkml.kernel.org/r/20161024082633.10148-1-jslaby@suse.cz
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoinitramfs: allow again choice of the embedded initram compression algorithm
Francisco Blas Izquierdo Riera (klondike) [Wed, 14 Dec 2016 23:06:04 +0000 (15:06 -0800)]
initramfs: allow again choice of the embedded initram compression algorithm

Choosing the appropriate compression option when using an embedded
initramfs can result in significant size differences in the resulting
data.

This is caused by avoiding double compression of the initramfs contents.
For example on my tests, choosing CONFIG_INITRAMFS_COMPRESSION_NONE when
compressing the kernel using XZ) results in up to 500KiB differences
(9MiB to 8.5MiB) in the kernel size as the dictionary will not get
polluted with uncomprensible data and may reuse kernel data too.

Despite embedding an uncompressed initramfs, a user may want to allow
for a compressed extra initramfs to be passed using the rd system, for
example to boot a recovery system.  9ba4bcb645898d ("initramfs: read
CONFIG_RD_ variables for initramfs compression") broke that behavior by
making the choice based on CONFIG_RD_* instead of adding
CONFIG_INITRAMFS_COMPRESSION_LZ4.  Saddly, CONFIG_RD_* is also used to
choose the supported RD compression algorithms by the kernel and a user
may want to support more than one.

This patch also reverts commit 3e4e0f0a875 ("initramfs: remove
"compression mode" choice") restoring back the "compression mode" choice
and includes the CONFIG_INITRAMFS_COMPRESSION_LZ4 option which was never
added.

As a result the following options are added or readed affecting the embedded
initramfs compression:
  INITRAMFS_COMPRESSION_NONE Do no compression
  INITRAMFS_COMPRESSION_GZIP Compress using gzip
  INITRAMFS_COMPRESSION_BZIP2 Compress using bzip2
  INITRAMFS_COMPRESSION_LZMA Compress using lzma
  INITRAMFS_COMPRESSION_XZ Compress using xz
  INITRAMFS_COMPRESSION_LZO Compress using lzo
  INITRAMFS_COMPRESSION_LZ4 Compress using lz4

These depend on the corresponding CONFIG_RD_* option being set (except
NONE which has no dependencies).

This patch depends on the previous one (the previous version didn't) to
simplify the way in which the algorithm is chosen and keep backwards
compatibility with the behaviour introduced by 9ba4bcb645898
("initramfs: read CONFIG_RD_ variables for initramfs compression").

Link: http://lkml.kernel.org/r/57EAD77B.7090607@klondike.es
Signed-off-by: Francisco Blas Izquierdo Riera (klondike) <klondike@klondike.es>
Cc: P J P <ppandit@redhat.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoinitramfs: select builtin initram compression algorithm on KConfig instead of Makefile
Francisco Blas Izquierdo Riera (klondike) [Wed, 14 Dec 2016 23:06:01 +0000 (15:06 -0800)]
initramfs: select builtin initram compression algorithm on KConfig instead of Makefile

Move the current builtin initram compression algorithm selection from
the Makefile into the INITRAMFS_COMPRESSION variable.  This makes
deciding algorithm precedence easier and would allow for overrides if
new algorithms want to be tested.

Link: http://lkml.kernel.org/r/57EAD769.1090401@klondike.es
Signed-off-by: Francisco Blas Izquierdo Riera (klondike) <klondike@klondike.es>
Cc: P J P <ppandit@redhat.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokdb: call vkdb_printf() from vprintk_default() only when wanted
Petr Mladek [Wed, 14 Dec 2016 23:05:58 +0000 (15:05 -0800)]
kdb: call vkdb_printf() from vprintk_default() only when wanted

kdb_trap_printk allows to pass normal printk() messages to kdb via
vkdb_printk().  For example, it is used to get backtrace using the
classic show_stack(), see kdb_show_stack().

vkdb_printf() tries to avoid a potential infinite loop by disabling the
trap.  But this approach is racy, for example:

CPU1 CPU2

vkdb_printf()
  // assume that kdb_trap_printk == 0
  saved_trap_printk = kdb_trap_printk;
  kdb_trap_printk = 0;

kdb_show_stack()
  kdb_trap_printk++;

Problem1: Now, a nested printk() on CPU0 calls vkdb_printf()
  even when it should have been disabled. It will not
  cause a deadlock but...

   // using the outdated saved value: 0
   kdb_trap_printk = saved_trap_printk;

  kdb_trap_printk--;

Problem2: Now, kdb_trap_printk == -1 and will stay like this.
   It means that all messages will get passed to kdb from
   now on.

This patch removes the racy saved_trap_printk handling.  Instead, the
recursion is prevented by a check for the locked CPU.

The solution is still kind of racy.  A non-related printk(), from
another process, might get trapped by vkdb_printf().  And the wanted
printk() might not get trapped because kdb_printf_cpu is assigned.  But
this problem existed even with the original code.

A proper solution would be to get_cpu() before setting kdb_trap_printk
and trap messages only from this CPU.  I am not sure if it is worth the
effort, though.

In fact, the race is very theoretical.  When kdb is running any of the
commands that use kdb_trap_printk there is a single active CPU and the
other CPUs should be in a holding pen inside kgdb_cpu_enter().

The only time this is violated is when there is a timeout waiting for
the other CPUs to report to the holding pen.

Finally, note that the situation is a bit schizophrenic.  vkdb_printf()
explicitly allows recursion but only from KDB code that calls
kdb_printf() directly.  On the other hand, the generic printk()
recursion is not allowed because it might cause an infinite loop.  This
is why we could not hide the decision inside vkdb_printf() easily.

Link: http://lkml.kernel.org/r/1480412276-16690-4-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokdb: properly synchronize vkdb_printf() calls with other CPUs
Petr Mladek [Wed, 14 Dec 2016 23:05:55 +0000 (15:05 -0800)]
kdb: properly synchronize vkdb_printf() calls with other CPUs

kdb_printf_lock does not prevent other CPUs from entering the critical
section because it is ignored when KDB_STATE_PRINTF_LOCK is set.

The problematic situation might look like:

CPU0 CPU1

vkdb_printf()
  if (!KDB_STATE(PRINTF_LOCK))
    KDB_STATE_SET(PRINTF_LOCK);
    spin_lock_irqsave(&kdb_printf_lock, flags);

vkdb_printf()
  if (!KDB_STATE(PRINTF_LOCK))

BANG: The PRINTF_LOCK state is set and CPU1 is entering the critical
section without spinning on the lock.

The problem is that the code tries to implement locking using two state
variables that are not handled atomically.  Well, we need a custom
locking because we want to allow reentering the critical section on the
very same CPU.

Let's use solution from Petr Zijlstra that was proposed for a similar
scenario, see
https://lkml.kernel.org/r/20161018171513.734367391@infradead.org

This patch uses the same trick with cmpxchg().  The only difference is
that we want to handle only recursion from the same context and
therefore we disable interrupts.

In addition, KDB_STATE_PRINTF_LOCK is removed.  In fact, we are not able
to set it a non-racy way.

Link: http://lkml.kernel.org/r/1480412276-16690-3-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokdb: remove unused kdb_event handling
Petr Mladek [Wed, 14 Dec 2016 23:05:52 +0000 (15:05 -0800)]
kdb: remove unused kdb_event handling

kdb_event state variable is only set but never checked in the kernel
code.

http://www.spinics.net/lists/kdb/msg01733.html suggests that this
variable affected WARN_CONSOLE_UNLOCKED() in the original
implementation.  But this check never went upstream.

The semantic is unclear and racy.  The value is updated after the
kdb_printf_lock is acquired and after it is released.  It should be
symmetric at minimum.  The value should be manipulated either inside or
outside the locked area.

Fortunately, it seems that the original function is gone and we could
simply remove the state variable.

Link: http://lkml.kernel.org/r/1480412276-16690-2-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokernel/debug/debug_core.c: more properly delay for secondary CPUs
Douglas Anderson [Wed, 14 Dec 2016 23:05:49 +0000 (15:05 -0800)]
kernel/debug/debug_core.c: more properly delay for secondary CPUs

We've got a delay loop waiting for secondary CPUs.  That loop uses
loops_per_jiffy.  However, loops_per_jiffy doesn't actually mean how
many tight loops make up a jiffy on all architectures.  It is quite
common to see things like this in the boot log:

  Calibrating delay loop (skipped), value calculated using timer
  frequency.. 48.00 BogoMIPS (lpj=24000)

In my case I was seeing lots of cases where other CPUs timed out
entering the debugger only to print their stack crawls shortly after the
kdb> prompt was written.

Elsewhere in kgdb we already use udelay(), so that should be safe enough
to use to implement our timeout.  We'll delay 1 ms for 1000 times, which
should give us a full second of delay (just like the old code wanted)
but allow us to notice that we're done every 1 ms.

[akpm@linux-foundation.org: simplifications, per Daniel]
Link: http://lkml.kernel.org/r/1477091361-2039-1-git-send-email-dianders@chromium.org
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Brian Norris <briannorris@chromium.org>
Cc: <stable@vger.kernel.org> [4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokcov: add more missing includes
Kefeng Wang [Wed, 14 Dec 2016 23:05:46 +0000 (15:05 -0800)]
kcov: add more missing includes

It is fragile that some definitions acquired via transitive
dependencies, as shown in below:

atomic_*        (<linux/atomic.h>)
ENOMEM/EN*      (<linux/errno.h>)
EXPORT_SYMBOL   (<linux/export.h>)
device_initcall (<linux/init.h>)
preempt_*       (<linux/preempt.h>)

Include them to prevent possible issues.

Link: http://lkml.kernel.org/r/1481163221-40170-1-git-send-email-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoKconfig: lib/Kconfig.ubsan fix reference to ubsan documentation
Andreas Platschek [Wed, 14 Dec 2016 23:05:43 +0000 (15:05 -0800)]
Kconfig: lib/Kconfig.ubsan fix reference to ubsan documentation

Documenation/ubsan.txt was moved to Documentation/dev-tools/ubsan.rst,
this fixes the reference.

Link: http://lkml.kernel.org/r/1476698152-29340-3-git-send-email-andreas.platschek@opentech.at
Signed-off-by: Andreas Platschek <andreas.platschek@opentech.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoKconfig: lib/Kconfig.debug: fix references to Documenation
Andreas Platschek [Wed, 14 Dec 2016 23:05:40 +0000 (15:05 -0800)]
Kconfig: lib/Kconfig.debug: fix references to Documenation

Documentation on development tools was moved to Documentation/devl-tools
and sphinxified (renamed from .txt to .rst).

References in lib/Kconfig.debug need to be updated to the new location.

Link: http://lkml.kernel.org/r/1476698152-29340-2-git-send-email-andreas.platschek@opentech.at
Signed-off-by: Andreas Platschek <andreas.platschek@opentech.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agorelay: check array offset before using it
Dan Carpenter [Wed, 14 Dec 2016 23:05:38 +0000 (15:05 -0800)]
relay: check array offset before using it

Smatch complains that we started using the array offset before we
checked that it was valid.

Fixes: 017c59c042d0 ('relay: Use per CPU constructs for the relay channel buffer pointers')
Link: http://lkml.kernel.org/r/20161013084947.GC16198@mwanda
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoigb: update code to better handle incrementing page count
Alexander Duyck [Wed, 14 Dec 2016 23:05:34 +0000 (15:05 -0800)]
igb: update code to better handle incrementing page count

Update the driver code so that we do bulk updates of the page reference
count instead of just incrementing it by one reference at a time.  The
advantage to doing this is that we cut down on atomic operations and
this in turn should give us a slight improvement in cycles per packet.
In addition if we eventually move this over to using build_skb the gains
will be more noticeable.

Link: http://lkml.kernel.org/r/20161110113616.76501.17072.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Cc: Helge Deller <deller@gmx.de>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoigb: update driver to make use of DMA_ATTR_SKIP_CPU_SYNC
Alexander Duyck [Wed, 14 Dec 2016 23:05:30 +0000 (15:05 -0800)]
igb: update driver to make use of DMA_ATTR_SKIP_CPU_SYNC

The ARM architecture provides a mechanism for deferring cache line
invalidation in the case of map/unmap.  This patch makes use of this
mechanism to avoid unnecessary synchronization.

A secondary effect of this change is that the portion of the page that
has been synchronized for use by the CPU should be writable and could be
passed up the stack (at least on ARM).

The last bit that occurred to me is that on architectures where the
sync_for_cpu call invalidates cache lines we were prefetching and then
invalidating the first 128 bytes of the packet.  To avoid that I have
moved the sync up to before we perform the prefetch and allocate the
skbuff so that we can actually make use of it.

Link: http://lkml.kernel.org/r/20161110113611.76501.98897.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Cc: Helge Deller <deller@gmx.de>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm: add support for releasing multiple instances of a page
Alexander Duyck [Wed, 14 Dec 2016 23:05:26 +0000 (15:05 -0800)]
mm: add support for releasing multiple instances of a page

Add a function that allows us to batch free a page that has multiple
references outstanding.  Specifically this function can be used to drop
a page being used in the page frag alloc cache.  With this drivers can
make use of functionality similar to the page frag alloc cache without
having to do any workarounds for the fact that there is no function that
frees multiple references.

Link: http://lkml.kernel.org/r/20161110113606.76501.70752.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Cc: Helge Deller <deller@gmx.de>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agodma: add calls for dma_map_page_attrs and dma_unmap_page_attrs
Alexander Duyck [Wed, 14 Dec 2016 23:05:23 +0000 (15:05 -0800)]
dma: add calls for dma_map_page_attrs and dma_unmap_page_attrs

Add support for mapping and unmapping a page with attributes.

The primary use for this is currently to allow for us to pass the
DMA_ATTR_SKIP_CPU_SYNC attribute when mapping and unmapping a page.  On
some architectures such as ARM the synchronization has significant
overhead and if we are already taking care of the sync_for_cpu and
sync_for_device from the driver there isn't much need to handle this in
the map/unmap calls as well.

Link: http://lkml.kernel.org/r/20161110113601.76501.46095.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/xtensa: add option to skip DMA sync as a part of mapping
Alexander Duyck [Wed, 14 Dec 2016 23:05:21 +0000 (15:05 -0800)]
arch/xtensa: add option to skip DMA sync as a part of mapping

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113555.76501.52536.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/tile: add option to skip DMA sync as a part of map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:05:18 +0000 (15:05 -0800)]
arch/tile: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113550.76501.73060.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/sparc: add option to skip DMA sync as a part of map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:05:15 +0000 (15:05 -0800)]
arch/sparc: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113544.76501.40008.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/sh: add option to skip DMA sync as a part of mapping
Alexander Duyck [Wed, 14 Dec 2016 23:05:12 +0000 (15:05 -0800)]
arch/sh: add option to skip DMA sync as a part of mapping

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113539.76501.6539.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/powerpc: add option to skip DMA sync as a part of mapping
Alexander Duyck [Wed, 14 Dec 2016 23:05:09 +0000 (15:05 -0800)]
arch/powerpc: add option to skip DMA sync as a part of mapping

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113534.76501.86492.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/parisc: add option to skip DMA sync as a part of map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:05:06 +0000 (15:05 -0800)]
arch/parisc: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113529.76501.44762.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/openrisc: add option to skip DMA sync as a part of mapping
Alexander Duyck [Wed, 14 Dec 2016 23:05:03 +0000 (15:05 -0800)]
arch/openrisc: add option to skip DMA sync as a part of mapping

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113524.76501.87966.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/nios2: add option to skip DMA sync as a part of map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:05:00 +0000 (15:05 -0800)]
arch/nios2: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113518.76501.52225.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Reviewed-by: Tobias Klauser <tklauser@distanz.ch>
Cc: Ley Foon Tan <lftan@altera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/mips: add option to skip DMA sync as a part of map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:04:58 +0000 (15:04 -0800)]
arch/mips: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113513.76501.32321.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/microblaze: add option to skip DMA sync as a part of map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:04:55 +0000 (15:04 -0800)]
arch/microblaze: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113508.76501.77583.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/metag: add option to skip DMA sync as a part of map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:04:52 +0000 (15:04 -0800)]
arch/metag: add option to skip DMA sync as a part of map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113503.76501.80809.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/m68k: add option to skip DMA sync as a part of mapping
Alexander Duyck [Wed, 14 Dec 2016 23:04:49 +0000 (15:04 -0800)]
arch/m68k: add option to skip DMA sync as a part of mapping

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
later via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113457.76501.77603.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/hexagon: Add option to skip DMA sync as a part of mapping
Alexander Duyck [Wed, 14 Dec 2016 23:04:46 +0000 (15:04 -0800)]
arch/hexagon: Add option to skip DMA sync as a part of mapping

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
later via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113452.76501.45864.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/frv: add option to skip sync on DMA map
Alexander Duyck [Wed, 14 Dec 2016 23:04:43 +0000 (15:04 -0800)]
arch/frv: add option to skip sync on DMA map

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the
DMA APIs in the arch/arm folder.  This change is meant to correct that
so that we get consistent behavior.

Link: http://lkml.kernel.org/r/20161110113447.76501.93160.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/c6x: add option to skip sync on DMA map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:04:41 +0000 (15:04 -0800)]
arch/c6x: add option to skip sync on DMA map and unmap

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
later via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113442.76501.7673.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/blackfin: add option to skip sync on DMA map
Alexander Duyck [Wed, 14 Dec 2016 23:04:38 +0000 (15:04 -0800)]
arch/blackfin: add option to skip sync on DMA map

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the
DMA APIs in the arch/arm folder.  This change is meant to correct that
so that we get consistent behavior.

Link: http://lkml.kernel.org/r/20161110113436.76501.13386.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Steven Miao <realmz6@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/avr32: add option to skip sync on DMA map
Alexander Duyck [Wed, 14 Dec 2016 23:04:35 +0000 (15:04 -0800)]
arch/avr32: add option to skip sync on DMA map

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the
DMA APIs in the arch/arm folder.  This change is meant to correct that
so that we get consistent behavior.

Link: http://lkml.kernel.org/r/20161110113430.76501.79737.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/arm: add option to skip sync on DMA map and unmap
Alexander Duyck [Wed, 14 Dec 2016 23:04:32 +0000 (15:04 -0800)]
arch/arm: add option to skip sync on DMA map and unmap

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the
DMA APIs in the arch/arm folder.  This change is meant to correct that
so that we get consistent behavior.

Link: http://lkml.kernel.org/r/20161110113424.76501.2715.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoarch/arc: add option to skip sync on DMA mapping
Alexander Duyck [Wed, 14 Dec 2016 23:04:29 +0000 (15:04 -0800)]
arch/arc: add option to skip sync on DMA mapping

Patch series "Add support for DMA writable pages being writable by the
network stack", v3.

The first 19 patches in the set add support for the DMA attribute
DMA_ATTR_SKIP_CPU_SYNC on multiple platforms/architectures.  This is
needed so that we can flag the calls to dma_map/unmap_page so that we do
not invalidate cache lines that do not currently belong to the device.
Instead we have to take care of this in the driver via a call to
sync_single_range_for_cpu prior to freeing the Rx page.

Patch 20 adds support for dma_map_page_attrs and dma_unmap_page_attrs so
that we can unmap and map a page using the DMA_ATTR_SKIP_CPU_SYNC
attribute.

Patch 21 adds support for freeing a page that has multiple references
being held by a single caller.  This way we can free page fragments that
were allocated by a given driver.

The last 2 patches use these updates in the igb driver, and lay the
groundwork to allow for us to reimplement the use of build_skb.

This patch (of 23):

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
later via a sync_for_cpu or sync_for_device call.

Link: http://lkml.kernel.org/r/20161110113419.76501.38491.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agosysctl: add KERN_CONT to deprecated_sysctl_warning()
Tetsuo Handa [Wed, 14 Dec 2016 23:04:26 +0000 (15:04 -0800)]
sysctl: add KERN_CONT to deprecated_sysctl_warning()

Do not break lines while printk()ing values.

  kernel: warning: process `tomoyo_file_tes' used the deprecated sysctl system call with
  kernel: 3.
  kernel: 5.
  kernel: 56.
  kernel:

Link: http://lkml.kernel.org/r/1480814833-4976-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokexec: add cond_resched into kimage_alloc_crash_control_pages
zhong jiang [Wed, 14 Dec 2016 23:04:23 +0000 (15:04 -0800)]
kexec: add cond_resched into kimage_alloc_crash_control_pages

A soft lookup will occur when I run trinity in syscall kexec_load.  the
corresponding stack information is as follows.

  BUG: soft lockup - CPU#6 stuck for 22s! [trinity-c6:13859]
  Kernel panic - not syncing: softlockup: hung tasks
  CPU: 6 PID: 13859 Comm: trinity-c6 Tainted: G           O L ----V-------   3.10.0-327.28.3.35.zhongjiang.x86_64 #1
  Hardware name: Huawei Technologies Co., Ltd. Tecal BH622 V2/BC01SRSA0, BIOS RMIBV386 06/30/2014
  Call Trace:
   <IRQ>  dump_stack+0x19/0x1b
   panic+0xd8/0x214
   watchdog_timer_fn+0x1cc/0x1e0
   __hrtimer_run_queues+0xd2/0x260
   hrtimer_interrupt+0xb0/0x1e0
   ? call_softirq+0x1c/0x30
   local_apic_timer_interrupt+0x37/0x60
   smp_apic_timer_interrupt+0x3f/0x60
   apic_timer_interrupt+0x6d/0x80
   <EOI>  ? kimage_alloc_control_pages+0x80/0x270
   ? kmem_cache_alloc_trace+0x1ce/0x1f0
   ? do_kimage_alloc_init+0x1f/0x90
   kimage_alloc_init+0x12a/0x180
   SyS_kexec_load+0x20a/0x260
   system_call_fastpath+0x16/0x1b

the first time allocation of control pages may take too much time
because crash_res.end can be set to a higher value.  we need to add
cond_resched to avoid the issue.

The patch have been tested and above issue is not appear.

Link: http://lkml.kernel.org/r/1481164674-42775-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokexec: export the value of phys_base instead of symbol address
Baoquan He [Wed, 14 Dec 2016 23:04:20 +0000 (15:04 -0800)]
kexec: export the value of phys_base instead of symbol address

Currently in x86_64, the symbol address of phys_base is exported to
vmcoreinfo.  Dave Anderson complained this is really useless for his
Crash implementation.  Because in user-space utility Crash and
Makedumpfile which exported vmcore information is mainly used for, value
of phys_base is needed to covert virtual address of exported kernel
symbol to physical address.  Especially init_level4_pgt, if we want to
access and go over the page table to look up a PA corresponding to VA,
firstly we need calculate

  page_dir = SYMBOL(init_level4_pgt) - __START_KERNEL_map + phys_base;

Now in Crash and Makedumpfile, we have to analyze the vmcore elf program
header to get value of phys_base.  As Dave said, it would be preferable
if it were readily availabl in vmcoreinfo rather than depending upon the
PT_LOAD semantics.

Hence in this patch change to export the value of phys_base instead of
its virtual address.

And people also complained that KERNEL_IMAGE_SIZE exporting is x86_64
only, should be moved into arch dependent function
arch_crash_save_vmcoreinfo.  Do the moving in this patch.

Link: http://lkml.kernel.org/r/1478568596-30060-2-git-send-email-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Eugene Surovegin <surovegin@google.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoRevert "kdump, vmcoreinfo: report memory sections virtual addresses"
Baoquan He [Wed, 14 Dec 2016 23:04:16 +0000 (15:04 -0800)]
Revert "kdump, vmcoreinfo: report memory sections virtual addresses"

This reverts commit 0549a3c02efb ("kdump, vmcoreinfo: report memory
sections virtual addresses").

Commit 0549a3c02efb tells the userspace utility makedumpfile the
randomized base address of these memmory sections when mm kaslr is
enabled.  However the following patch "kexec: export the value of
phys_base instead of symbol address" makes makedumpfile not need these
addresses any more.

Besides we should use VMCOREINFO_NUMBER to export the value of the
variable so that we can use the existing number_table mechanism of
Makedumpfile to fetch it.  So revert it now.  If needed we can add it
later.

http://lists.infradead.org/pipermail/kexec/2016-October/017540.html
Link: http://lkml.kernel.org/r/1478568596-30060-1-git-send-email-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Eugene Surovegin <surovegin@google.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agocoredump: clarify "unsafe core_pattern" warning
Alexey Dobriyan [Wed, 14 Dec 2016 23:04:14 +0000 (15:04 -0800)]
coredump: clarify "unsafe core_pattern" warning

I was amused to find "unsafe core_pattern" warning having these lines in
/etc/sysctl.conf:

fs.suid_dumpable=2
kernel.core_pattern=/core/core-%e-%p-%E
kernel.core_uses_pid=0

Turns out kernel is formally right.  Default core_pattern is just "core",
which doesn't qualify for secure path while setting suid.dumpable.

Hint admins about solution, clarify sysctl names, delete unnecessary '\'
characters (string literals are concatenated regardless) and reformat for
easier grepping.

Link: http://lkml.kernel.org/r/20161029152124.GA1258@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agosignals: avoid unnecessary taking of sighand->siglock
Waiman Long [Wed, 14 Dec 2016 23:04:10 +0000 (15:04 -0800)]
signals: avoid unnecessary taking of sighand->siglock

When running certain database workload on a high-end system with many
CPUs, it was found that spinlock contention in the sigprocmask syscalls
became a significant portion of the overall CPU cycles as shown below.

  9.30%  9.30%  905387  dataserver  /proc/kcore 0x7fff8163f4d2
  [k] _raw_spin_lock_irq
            |
            ---_raw_spin_lock_irq
               |
               |--99.34%-- __set_current_blocked
               |          sigprocmask
               |          sys_rt_sigprocmask
               |          system_call_fastpath
               |          |
               |          |--50.63%-- __swapcontext
               |          |          |
               |          |          |--99.91%-- upsleepgeneric
               |          |
               |          |--49.36%-- __setcontext
               |          |          ktskRun

Looking further into the swapcontext function in glibc, it was found that
the function always call sigprocmask() without checking if there are
changes in the signal mask.

A check was added to the __set_current_blocked() function to avoid taking
the sighand->siglock spinlock if there is no change in the signal mask.
This will prevent unneeded spinlock contention when many threads are
trying to call sigprocmask().

With this patch applied, the spinlock contention in sigprocmask() was
gone.

Link: http://lkml.kernel.org/r/1474979209-11867-1-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agomm, compaction: allow compaction for GFP_NOFS requests
Michal Hocko [Wed, 14 Dec 2016 23:04:07 +0000 (15:04 -0800)]
mm, compaction: allow compaction for GFP_NOFS requests

compaction has been disabled for GFP_NOFS and GFP_NOIO requests since
the direct compaction was introduced by commit 56de7263fcf3 ("mm:
compaction: direct compact when a high-order allocation fails").  The
main reason is that the migration of page cache pages might recurse back
to fs/io layer and we could potentially deadlock.  This is overly
conservative because all the anonymous memory is migrateable in the
GFP_NOFS context just fine.  This might be a large portion of the memory
in many/most workkloads.

Remove the GFP_NOFS restriction and make sure that we skip all fs pages
(those with a mapping) while isolating pages to be migrated.  We cannot
consider clean fs pages because they might need a metadata update so
only isolate pages without any mapping for nofs requests.

The effect of this patch will be probably very limited in many/most
workloads because higher order GFP_NOFS requests are quite rare,
although different configurations might lead to very different results.
David Chinner has mentioned a heavy metadata workload with 64kB block
which to quote him:

: Unfortunately, there was an era of cargo cult configuration tweaks in the
: Ceph community that has resulted in a large number of production machines
: with XFS filesystems configured this way.  And a lot of them store large
: numbers of small files and run under significant sustained memory
: pressure.
:
: I slowly working towards getting rid of these high order allocations and
: replacing them with the equivalent number of single page allocations, but
: I haven't got that (complex) change working yet.

We can do the following to simulate that workload:
$ mkfs.xfs -f -n size=64k <dev>
$ mount <dev> /mnt/scratch
$ time ./fs_mark  -D  10000  -S0  -n  100000  -s  0  -L  32 \
        -d  /mnt/scratch/0  -d  /mnt/scratch/1 \
        -d  /mnt/scratch/2  -d  /mnt/scratch/3 \
        -d  /mnt/scratch/4  -d  /mnt/scratch/5 \
        -d  /mnt/scratch/6  -d  /mnt/scratch/7 \
        -d  /mnt/scratch/8  -d  /mnt/scratch/9 \
        -d  /mnt/scratch/10  -d  /mnt/scratch/11 \
        -d  /mnt/scratch/12  -d  /mnt/scratch/13 \
        -d  /mnt/scratch/14  -d  /mnt/scratch/15

and indeed is hammers the system with many high order GFP_NOFS requests as
per a simle tracepoint during the load:
$ echo '!(gfp_flags & 0x80) && (gfp_flags &0x400000)' > $TRACE_MNT/events/kmem/mm_page_alloc/filter
I am getting
5287609 order=0
     37 order=1
1594905 order=2
3048439 order=3
6699207 order=4
  66645 order=5

My testing was done in a kvm guest so performance numbers should be
taken with a grain of salt but there seems to be a difference when the
patch is applied:

* Original kernel
FSUse%        Count         Size    Files/sec     App Overhead
     1      1600000            0       4300.1         20745838
     3      3200000            0       4239.9         23849857
     5      4800000            0       4243.4         25939543
     6      6400000            0       4248.4         19514050
     8      8000000            0       4262.1         20796169
     9      9600000            0       4257.6         21288675
    11     11200000            0       4259.7         19375120
    13     12800000            0       4220.7         22734141
    14     14400000            0       4238.5         31936458
    16     16000000            0       4231.5         23409901
    18     17600000            0       4045.3         23577700
    19     19200000            0       2783.4         58299526
    21     20800000            0       2678.2         40616302
    23     22400000            0       2693.5         83973996

and xfs complaining about memory allocation not making progress
[ 2304.372647] XFS: fs_mark(3289) possible memory allocation deadlock size 65624 in kmem_alloc (mode:0x2408240)
[ 2304.443323] XFS: fs_mark(3285) possible memory allocation deadlock size 65728 in kmem_alloc (mode:0x2408240)
[ 4796.772477] XFS: fs_mark(3424) possible memory allocation deadlock size 46936 in kmem_alloc (mode:0x2408240)
[ 4796.775329] XFS: fs_mark(3423) possible memory allocation deadlock size 51416 in kmem_alloc (mode:0x2408240)
[ 4797.388808] XFS: fs_mark(3424) possible memory allocation deadlock size 65728 in kmem_alloc (mode:0x2408240)

* Patched kernel
FSUse%        Count         Size    Files/sec     App Overhead
     1      1600000            0       4289.1         19243934
     3      3200000            0       4241.6         32828865
     5      4800000            0       4248.7         32884693
     6      6400000            0       4314.4         19608921
     8      8000000            0       4269.9         24953292
     9      9600000            0       4270.7         33235572
    11     11200000            0       4346.4         40817101
    13     12800000            0       4285.3         29972397
    14     14400000            0       4297.2         20539765
    16     16000000            0       4219.6         18596767
    18     17600000            0       4273.8         49611187
    19     19200000            0       4300.4         27944451
    21     20800000            0       4270.6         22324585
    22     22400000            0       4317.6         22650382
    24     24000000            0       4065.2         22297964

So the dropdown at Count 19200000 didn't happen and there was only a
single warning about allocation not making progress
[ 3063.815003] XFS: fs_mark(3272) possible memory allocation deadlock size 65624 in kmem_alloc (mode:0x2408240)

This suggests that the patch has helped even though there is not all that
much of anonymous memory as the workload mostly generates fs metadata.  I
assume the success rate would be higher with more anonymous memory which
should be the case in many workloads.

[akpm@linux-foundation.org: fix comment]
Link: http://lkml.kernel.org/r/20161012114721.31853-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agokernel/watchdog: use nmi registers snapshot in hardlockup handler
Konstantin Khlebnikov [Wed, 14 Dec 2016 23:04:04 +0000 (15:04 -0800)]
kernel/watchdog: use nmi registers snapshot in hardlockup handler

NMI handler doesn't call set_irq_regs(), it's set only by normal IRQ.
Thus get_irq_regs() returns NULL or stale registers snapshot with IP/SP
pointing to the code interrupted by IRQ which was interrupted by NMI.
NULL isn't a problem: in this case watchdog calls dump_stack() and
prints full stack trace including NMI.  But if we're stuck in IRQ
handler then NMI watchlog will print stack trace without IRQ part at
all.

This patch uses registers snapshot passed into NMI handler as arguments:
these registers point exactly to the instruction interrupted by NMI.

Fixes: 55537871ef66 ("kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup")
Link: http://lkml.kernel.org/r/146771764784.86724.6006627197118544150.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: <stable@vger.kernel.org> [4.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agobtrfs: better handle btrfs_printk() defaults
Petr Mladek [Wed, 14 Dec 2016 23:04:01 +0000 (15:04 -0800)]
btrfs: better handle btrfs_printk() defaults

Commit 262c5e86fec7 ("printk/btrfs: handle more message headers")
triggers:

    warning: `ratelimit' may be used uninitialized in this function

with gcc (4.1.2) and probably many other versions.  The code actually is
correct but a bit twisted.  Let's make it more straightforward and set
the default values at the beginning.

Link: http://lkml.kernel.org/r/20161213135246.GQ3506@pathway.suse.cz
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoMerge tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device...
Linus Torvalds [Wed, 14 Dec 2016 19:01:00 +0000 (11:01 -0800)]
Merge tag 'dm-4.10-changes' of git://git./linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - various fixes and improvements to request-based DM and DM multipath

 - some locking improvements in DM bufio

 - add Kconfig option to disable the DM block manager's extra locking
   which mainly serves as a developer tool

 - a few bug fixes to DM's persistent-data

 - a couple changes to prepare for multipage biovec support in the block
   layer

 - various improvements and cleanups in the DM core, DM cache, DM raid
   and DM crypt

 - add ability to have DM crypt use keys from the kernel key retention
   service

 - add a new "error_writes" feature to the DM flakey target, reads are
   left unchanged in this mode

* tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (40 commits)
  dm flakey: introduce "error_writes" feature
  dm cache policy smq: use hash_32() instead of hash_32_generic()
  dm crypt: reject key strings containing whitespace chars
  dm space map: always set ev if sm_ll_mutate() succeeds
  dm space map metadata: skip useless memcpy in metadata_ll_init_index()
  dm space map metadata: fix 'struct sm_metadata' leak on failed create
  Documentation: dm raid: define data_offset status field
  dm raid: fix discard support regression
  dm raid: don't allow "write behind" with raid4/5/6
  dm mpath: use hw_handler_params if attached hw_handler is same as requested
  dm crypt: add ability to use keys from the kernel key retention service
  dm array: remove a dead assignment in populate_ablock_with_values()
  dm ioctl: use offsetof() instead of open-coding it
  dm rq: simplify use_blk_mq initialization
  dm: use blk_set_queue_dying() in __dm_destroy()
  dm bufio: drop the lock when doing GFP_NOIO allocation
  dm bufio: don't take the lock in dm_bufio_shrink_count
  dm bufio: avoid sleeping while holding the dm_bufio lock
  dm table: simplify dm_table_determine_type()
  dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device
  ...

7 years agoMerge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md
Linus Torvalds [Wed, 14 Dec 2016 18:58:17 +0000 (10:58 -0800)]
Merge branch 'for-linus' of git://git./linux/kernel/git/shli/md

Pull MD updates from Shaohua Li:

 - a raid5 writeback cache feature.

   The goal is to aggregate writes to make full stripe write and reduce
   read-modify-write. It's helpful for workload which does sequential
   write and follows fsync for example. This feature is experimental and
   off by default right now.

 - FAILFAST support.

   This fails IOs to broken raid disks quickly, so can improve latency.
   It's mainly for DASD storage, but some patches help normal raid array
   too.

 - support bad block for raid array with external metadata

 - AVX2 instruction support for raid6 parity calculation

 - normalize MD info output

 - add missing blktrace

 - other bug fixes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: (66 commits)
  md: separate flags for superblock changes
  md: MD_RECOVERY_NEEDED is set for mddev->recovery
  md: takeover should clear unrelated bits
  md/r5cache: after recovery, increase journal seq by 10000
  md/raid5-cache: fix crc in rewrite_data_only_stripes()
  md/raid5-cache: no recovery is required when create super-block
  md: fix refcount problem on mddev when stopping array.
  md/r5cache: do r5c_update_log_state after log recovery
  md/raid5-cache: adjust the write position of the empty block if no data blocks
  md/r5cache: run_no_space_stripes() when R5C_LOG_CRITICAL == 0
  md/raid5: limit request size according to implementation limits
  md/raid5-cache: do not need to set STRIPE_PREREAD_ACTIVE repeatedly
  md/raid5-cache: remove the unnecessary next_cp_seq field from the r5l_log
  md/raid5-cache: release the stripe_head at the appropriate location
  md/raid5-cache: use ring add to prevent overflow
  md/raid5-cache: remove unnecessary function parameters
  raid5-cache: don't set STRIPE_R5C_PARTIAL_STRIPE flag while load stripe into cache
  raid5-cache: add another check conditon before replaying one stripe
  md/r5cache: enable IRQs on error path
  md/r5cache: handle alloc_page failure
  ...