cpumask, nodemask: implement cpumask/nodemask_pr_args()

printf family of functions can now format bitmaps using '%*pb[l]' and
all cpumask and nodemask formatting will be converted to use it.  To
ease printing these masks with '%*pb[l]' which require two params -
the number of bits and the actual bitmap, this patch implement
cpumask_pr_args() and nodemask_pr_args() which can be used to provide
arguments for '%*pb[l]'

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/vsprintf: implement bitmap printing through '%*pb[l]'

bitmap and its derivatives such as cpumask and nodemask currently only
provide formatting functions which put the output string into the
provided buffer; however, how long this buffer should be isn't defined
anywhere and given that some of these bitmaps can be too large to be
formatted into an on-stack buffer it users sometimes are unnecessarily
forced to come up with creative solutions and compromises for the
buffer just to printk these bitmaps.

There have been a couple different attempts at making this easier.

1. Way back, PeterZ tried printk '%pb' extension with the precision
   for bit width - '%.*pb'.  This was intuitive and made sense but
   unfortunately triggered a compile warning about using precision
   for a pointer.

   http://lkml.kernel.org/g/1336577562.2527.58.camel@twins

2. I implemented bitmap_pr_cont[_list]() and its wrappers for cpumask
   and nodemask.  This works but PeterZ pointed out that pr_cont's
   tendency to produce broken lines when multiple CPUs are printing is
   bothering considering the usages.

   http://lkml.kernel.org/g/1418226774-30215-3-git-send-email-tj@kernel.org

So, this patch is another attempt at teaching printk and friends how
to print bitmaps.  It's almost identical to what PeterZ tried with
precision but it uses the field width for the number of bits instead
of precision.  The format used is '%*pb[l]', with the optional
trailing 'l' specifying list format instead of hex masks.

This is a valid format string and doesn't trigger compiler warnings;
however, it does make it impossible to specify output field width when
printing bitmaps.  I think this is an acceptable trade-off given how
much easier it makes printing bitmaps and that we don't have any
in-kernel user which is using the field width specification.  If any
future user wants to use field width with a bitmap, it'd have to
format the bitmap into a string buffer and then print that buffer with
width spec, which isn't different from how it should be done now.

This patch implements bitmap[_list]_string() which are called from the
vsprintf pointer() formatting function.  The implementation is mostly
identical to bitmap_scn[list]printf() except that the output is
performed in the vsprintf way.  These functions handle formatting into
too small buffers and sprintf() family of functions report the correct
overrun output length.

bitmap_scn[list]printf() are now thin wrappers around scnprintf().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

cpumask: always use nr_cpu_ids in formatting and parsing functions

bitmap implements two variants of scnprintf functions to format a bitmap
into a string and cpumask and nodemask wrap them to provide equivalent
interfaces.  The scnprintf family of functions require a string buffer as
an output target which complicates code paths which just want to print out
the mask through printk for informational or debug purposes as they have
to worry about how large the buffer should be and whether it's too large
to allocate on stack.

Neither cpumask or nodemask provides a guildeline on how large the target
buffer should be forcing users come up with their own solutions - some
allocate an arbitrarily sized buffer which is small enough to allocate on
stack but may be too short in corner cases, other come up with a custom
upper limit calculation considering the output format, some allocate the
buffer dynamically while one resorted to using lock to synchronize access
to a static buffer.

This is an artificial problem which is being solved repeatedly for no
benefit.  In a lot of cases, the output area already exists and can be
targeted directly making the intermediate buffer unnecessary.  This
patchset teaches printf family of functions how to format bitmaps and
replace the dedicated formatting functions with it.

Pointer formatting is extended to cover bitmap formatting.  It uses the
field width for the number of bits instead of precision.  The format used
is '%*pb[l]', with the optional trailing 'l' specifying list format
instead of hex masks.  For more details, please see 0002.

This patch (of 31):

Currently, the formatting and parsing functions in cpumask.h use
nr_cpumask_bits like other cpumask functions; however, nr_cpumask_bits
is either NR_CPUS or nr_cpu_ids depending on CONFIG_CPUMASK_OFFSTACK.
This leads to inconsistent behaviors.

With CONFIG_NR_CPUS=512 and !CONFIG_CPUMASK_OFFSTACK

  # cat /sys/devices/virtual/net/lo/queues/rx-0/rps_cpus
  00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000
  # cat /proc/self/status | grep Cpus_allowed:
  Cpus_allowed:   f

With CONFIG_NR_CPUS=1024 and CONFIG_CPUMASK_OFFSTACK (fedora default)

  # cat /sys/devices/virtual/net/lo/queues/rx-0/rps_cpus
  0
  # cat /proc/self/status | grep Cpus_allowed:
  Cpus_allowed:   f

Note that /proc/self/status is always using nr_cpu_ids regardless of
config.  This is because seq cpumask formattings functions always use
nr_cpu_ids.

Given that the same output fields may switch between the two forms,
converging on nr_cpu_ids always isn't too likely to surprise userland.
This patch updates the formatting and parsing functions in cpumask.h
to always use nr_cpu_ids.  There's no point in dealing with CPUs which
aren't even possible on the machine.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/genalloc.c: check result of devres_alloc()

devm_gen_pool_create() calls devres_alloc() and dereferences its result
without checking whether devres_alloc() succeeded.  Check for error and
bail out if it happened.

Coverity-id 1016493.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/string.c: improve strrchr()

Instead of potentially passing over the string twice in case c is not
found, just keep track of the last occurrence.  According to
bloat-o-meter, this also cuts the generated code by a third (54 vs 36
bytes).  Oh, and we get rid of those 7-space indented lines.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/namespace: convert devname allocation to kstrdup_const

VFS frequently performs duplication of strings located in read-only memory
section.  Replacing kstrdup by kstrdup_const allows to avoid such
operations.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg KH <greg@kroah.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>

mm/slab: convert cache name allocations to kstrdup_const

slab frequently performs duplication of strings located in read-only
memory section.  Replacing kstrdup by kstrdup_const allows to avoid such
operations.

[akpm@linux-foundation.org: make the handling of kmem_cache.name const-correct]
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg KH <greg@kroah.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>

clk: convert clock name allocations to kstrdup_const

Clock subsystem frequently performs duplication of strings located in
read-only memory section.  Replacing kstrdup by kstrdup_const allows to
avoid such operations.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg KH <greg@kroah.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>

kernfs: remove KERNFS_STATIC_NAME

When a new kernfs node is created, KERNFS_STATIC_NAME is used to avoid
making a separate copy of its name.  It's currently only used for sysfs
attributes whose filenames are required to stay accessible and unchanged.
There are rare exceptions where these names are allocated and formatted
dynamically but for the vast majority of cases they're consts in the
rodata section.

Now that kernfs is converted to use kstrdup_const() and kfree_const(),
there's little point in keeping KERNFS_STATIC_NAME around.  Remove it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernfs: convert node name allocation to kstrdup_const

sysfs frequently performs duplication of strings located in read-only
memory section.  Replacing kstrdup by kstrdup_const allows to avoid such
operations.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Greg KH <greg@kroah.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>

mm/util: add kstrdup_const

kstrdup() is often used to duplicate strings where neither source neither
destination will be ever modified.  In such case we can just reuse the
source instead of duplicating it.  The problem is that we must be sure
that the source is non-modifiable and its life-time is long enough.

I suspect the good candidates for such strings are strings located in
kernel .rodata section, they cannot be modifed because the section is
read-only and their life-time is equal to kernel life-time.

This small patchset proposes alternative version of kstrdup -
kstrdup_const, which returns source string if it is located in .rodata
otherwise it fallbacks to kstrdup.  To verify if the source is in
.rodata function checks if the address is between sentinels
__start_rodata, __end_rodata.  I guess it should work with all
architectures.

The main patch is accompanied by four patches constifying kstrdup for
cases where situtation described above happens frequently.

I have tested the patchset on mobile platform (exynos4210-trats) and it
saves 3272 string allocations.  Since minimal allocation is 32 or 64
bytes depending on Kconfig options the patchset saves respectively about
100KB or 200KB of memory.

Stats from tested platform show that the main offender is sysfs:

By caller:
  2260 __kernfs_new_node
    631 clk_register+0xc8/0x1b8
    318 clk_register+0x34/0x1b8
      51 kmem_cache_create
      12 alloc_vfsmnt

By string (with count >= 5):
    883 power
    876 subsystem
    135 parameters
    132 device
     61 iommu_group
    ...

This patch (of 5):

Add an alternative version of kstrdup which returns pointer to constant
char array.  The function checks if input string is in persistent and
read-only memory section, if yes it returns the input string, otherwise it
fallbacks to kstrdup.

kstrdup_const is accompanied by kfree_const performing conditional memory
deallocation of the string.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg KH <greg@kroah.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>

lib: crc32: constify crc32 lookup table

Commit 8f243af42ade ("sections: fix const sections for crc32 table")
removed the compile-time generated crc32 tables from the RO sections,
because it conflicts with the definition of __cacheline_aligned which
puts all such aligned data into .data..cacheline_aligned section
optimized for wasting less space, and can cause alignment issues when
used in combination with const with some gcc versions like 4.7.0 due to
a gcc bug [1].

Given that most gcc versions should have the fix by now, we can just use
____cacheline_aligned, which only aligns the data but doesn't move it
into specific sections as opposed to __cacheline_aligned.  In case of
gcc versions having the mentioned bug, the alignment attribute will have
no effect, but the data will still be made RO.

After patch tables are in RO:

  $ nm -v lib/crc32.o | grep -1 -E "crc32c?table"
  0000000000000000 t arch_local_irq_enable
  0000000000000000 r crc32ctable_le
  0000000000000000 t crc32_exit
  --
  0000000000000960 t test_buf
  0000000000002000 r crc32table_be
  0000000000004000 r crc32table_le
  000000001d1056e5 A __crc_crc32_be

  [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52181

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: bitmap: remove redundant code from __bitmap_shift_left

The first of these conditionals is completely redundant: If k == lim-1, we
must have off==0, so the second conditional will also trigger and then it
wouldn't matter if upper had some high bits set.  But the second
conditional is in fact also redundant, since it only serves to clear out
some high-order "don't care" bits of dst, about which no guarantee is
made.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: bitmap: eliminate branch in __bitmap_shift_left

We can shift the bits from lower and upper into place before assembling
dst[k + off]; moving the shift of lower into the branch where we already
know that rem is non-zero allows us to remove a conditional.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: bitmap: change bitmap_shift_left to take unsigned parameters

gcc can generate slightly better code for stuff like "nbits %
BITS_PER_LONG" when it knows nbits is not negative.  Since negative size
bitmaps or shift amounts don't make sense, change these parameters of
bitmap_shift_right to unsigned.

If off >= lim (which requires shift >= nbits), k is initialized with a
large positive value, but since I've let k continue to be signed, the loop
will never run and dst will be zeroed as expected.  Inside the loop, k is
guaranteed to be non-negative, so the fact that it is promoted to unsigned
in the various expressions it appears in is harmless.

Also use "shift" and "nbits" consistently for the parameter names.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: bitmap: yet another simplification in __bitmap_shift_right

If left is 0, we can just let mask be ~0UL, so that anding with it is a
no-op.  Conveniently, BITMAP_LAST_WORD_MASK provides precisely what we
need, and we can eliminate left.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: bitmap: remove redundant code from __bitmap_shift_right

If the condition k==lim-1 is true, we must have off == 0 (otherwise, k
could never become that big).  But in that case we have upper == 0 and
hence dst[k] == (src[k] & mask) >> rem.  Since mask consists of a
consecutive range of bits starting from the LSB, anding dst[k] with mask
is a no-op.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: bitmap: eliminate branch in __bitmap_shift_right

We can shift the bits from lower and upper into place before assembling
dst[k]; moving the shift of upper into the branch where we already know
that rem is non-zero allows us to remove a conditional.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: bitmap: change bitmap_shift_right to take unsigned parameters

I've previously changed the nbits parameter of most bitmap_* functions to
unsigned; now it is bitmap_shift_{left,right}'s turn.  This alone saves
some .text, but while at it I found that there were a few other things one
could do.  The end result of these seven patches is

  $ scripts/bloat-o-meter /tmp/bitmap.o.{old,new}
  add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-328 (-328)
  function                                     old     new   delta
  __bitmap_shift_right                         384     226    -158
  __bitmap_shift_left                          306     136    -170

and less importantly also a smaller stack footprint

  $ stack-o-meter.pl master bitmap
  file                 function                       old  new  delta
  lib/bitmap.o         __bitmap_shift_right             24    8  -16
  lib/bitmap.o         __bitmap_shift_left              24    0  -24

For each pair of 0 <= shift <= nbits <= 256 I've tested the end result
with a few randomly filled src buffers (including garbage beyond nbits),
in each case verifying that the shift {left,right}-most bits of dst are
zero and the remaining nbits-shift bits correspond to src, so I'm fairly
confident I didn't screw up.  That hasn't stopped me from being wrong
before, though.

This patch (of 7):

gcc can generate slightly better code for stuff like "nbits %
BITS_PER_LONG" when it knows nbits is not negative.  Since negative size
bitmaps or shift amounts don't make sense, change these parameters of
bitmap_shift_right to unsigned.

The expressions involving "lim - 1" are still ok, since if lim is 0 the
loop is never executed.

Also use "shift" and "nbits" consistently for the parameter names.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: elide bitmap_copy_le on little-endian

On little-endian, there's no reason to have an extra, presumably less
efficient, way of copying a bitmap.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: change prototype of bitmap_copy_le

Make the prototype of bitmap_copy_le the same as bitmap_copy's.  All other
bitmap_* functions take unsigned long* parameters; there's no reason this
should be special.

The only current user is the static inline uwb_mas_bm_copy_le, which
already does the void* laundering, so the end users can pass their u8 or
__le32 buffers without a cast.

Furthermore, this allows us to simply let bitmap_copy_le be an alias for
bitmap_copy on little-endian; see next patch.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'for-next' of git://git./linux/kernel/git/cooloney/linux-leds

Pull LED subsystem update from Bryan Wu:
 "The big change of LED subsystem is introducing a new LED class for
  Flash type LEDs which will be used for V4L2 subsystem.

  Also we got some cleanup and fixes"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds:
  leds: leds-gpio: Pass on error codes unmodified
  DT: leds: Add led-sources property
  leds: Add LED Flash class extension to the LED subsystem
  leds: leds-mc13783: Use of_get_child_by_name() instead of refcount hack
  leds: Use setup_timer
  leds: Don't allow brightness values greater than max_brightness
  DT: leds: Add flash LED devices related properties

Merge tag 'modules-next-for-linus' of git://git./linux/kernel/git/rusty/linux

Pull module update from Rusty Russell:
 "Trivial cleanups, mainly"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: Replace over-engineered nested sleep
  module: Annotate nested sleep in resolve_symbol()
  module: Remove double spaces in module verification taint message
  kernel/module.c: Free lock-classes if parse_args failed
  module: set ksymtab/kcrctab* section addresses to 0x0

Merge git://git./linux/kernel/git/cmetcalf/linux-tile

Pull arch/tile changes from Chris Metcalf:
 "Not much in this batch, just some minor cleanups"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: change MAINTAINERS website from tilera.com to ezchip.com
  tile: enable sparse checks for get/put_user
  tile: fix put_user sparse errors
  tile: default to little endian on older toolchains

Revert "x86/apic: Only disable CPU x2apic mode when necessary"

This reverts commit 5fcee53ce705d49c766f8a302c7e93bdfc33c124.

It causes the suspend to fail on at least the Chromebook Pixel, possibly
other platforms too.

Joerg Roedel points out that the logic should probably have been

                if (max_physical_apicid > 255 ||
                    !(IS_ENABLED(CONFIG_HYPERVISOR_GUEST) &&
                      hypervisor_x2apic_available())) {

instead, but since the code is not in any fast-path, so we can just live
without that optimization and just revert to the original code.

Acked-by: Joerg Roedel <joro@8bytes.org>
Acked-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tile: change MAINTAINERS website from tilera.com to ezchip.com

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

Merge tag 'for-linus' of git://git./virt/kvm/kvm

Pull KVM update from Paolo Bonzini:
 "Fairly small update, but there are some interesting new features.

  Common:
     Optional support for adding a small amount of polling on each HLT
     instruction executed in the guest (or equivalent for other
     architectures).  This can improve latency up to 50% on some
     scenarios (e.g. O_DSYNC writes or TCP_RR netperf tests).  This
     also has to be enabled manually for now, but the plan is to
     auto-tune this in the future.

  ARM/ARM64:
     The highlights are support for GICv3 emulation and dirty page
     tracking

  s390:
     Several optimizations and bugfixes.  Also a first: a feature
     exposed by KVM (UUID and long guest name in /proc/sysinfo) before
     it is available in IBM's hypervisor! :)

  MIPS:
     Bugfixes.

  x86:
     Support for PML (page modification logging, a new feature in
     Broadwell Xeons that speeds up dirty page tracking), nested
     virtualization improvements (nested APICv---a nice optimization),
     usual round of emulation fixes.

     There is also a new option to reduce latency of the TSC deadline
     timer in the guest; this needs to be tuned manually.

     Some commits are common between this pull and Catalin's; I see you
     have already included his tree.

  Powerpc:
     Nothing yet.

     The KVM/PPC changes will come in through the PPC maintainers,
     because I haven't received them yet and I might end up being
     offline for some part of next week"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits)
  KVM: ia64: drop kvm.h from installed user headers
  KVM: x86: fix build with !CONFIG_SMP
  KVM: x86: emulate: correct page fault error code for NoWrite instructions
  KVM: Disable compat ioctl for s390
  KVM: s390: add cpu model support
  KVM: s390: use facilities and cpu_id per KVM
  KVM: s390/CPACF: Choose crypto control block format
  s390/kernel: Update /proc/sysinfo file with Extended Name and UUID
  KVM: s390: reenable LPP facility
  KVM: s390: floating irqs: fix user triggerable endless loop
  kvm: add halt_poll_ns module parameter
  kvm: remove KVM_MMIO_SIZE
  KVM: MIPS: Don't leak FPU/DSP to guest
  KVM: MIPS: Disable HTW while in guest
  KVM: nVMX: Enable nested posted interrupt processing
  KVM: nVMX: Enable nested virtual interrupt delivery
  KVM: nVMX: Enable nested apic register virtualization
  KVM: nVMX: Make nested control MSRs per-cpu
  KVM: nVMX: Enable nested virtualize x2apic mode
  KVM: nVMX: Prepare for using hardware MSR bitmap
  ...

Merge tag 'for-f2fs-3.20' of git://git./linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "Major changes are to:
   - add f2fs_io_tracer and F2FS_IOC_GETVERSION
   - fix wrong acl assignment from parent
   - fix accessing wrong data blocks
   - fix wrong condition check for f2fs_sync_fs
   - align start block address for direct_io
   - add and refactor the readahead flows of FS metadata
   - refactor atomic and volatile write policies

  But most of patches are for clean-ups and minor bug fixes.  Some of
  them refactor old code too"

* tag 'for-f2fs-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (64 commits)
  f2fs: use spinlock for segmap_lock instead of rwlock
  f2fs: fix accessing wrong indexed data blocks
  f2fs: avoid variable length array
  f2fs: fix sparse warnings
  f2fs: allocate data blocks in advance for f2fs_direct_IO
  f2fs: introduce macros to convert bytes and blocks in f2fs
  f2fs: call set_buffer_new for get_block
  f2fs: check node page contents all the time
  f2fs: avoid data offset overflow when lseeking huge file
  f2fs: fix to use highmem for pages of newly created directory
  f2fs: introduce a batched trim
  f2fs: merge {invalidate,release}page for meta/node/data pages
  f2fs: show the number of writeback pages in stat
  f2fs: keep PagePrivate during releasepage
  f2fs: should fail mount when trying to recover data on read-only dev
  f2fs: split UMOUNT and FASTBOOT flags
  f2fs: avoid write_checkpoint if f2fs is mounted readonly
  f2fs: support norecovery mount option
  f2fs: fix not to drop mount options when retrying fill_super
  f2fs: merge flags in struct f2fs_sb_info
  ...

Merge branch 'akpm' (patches from Andrew)

Merge third set of updates from Andrew Morton:

 - the rest of MM

   [ This includes getting rid of the numa hinting bits, in favor of
     just generic protnone logic.  Yay.     - Linus ]

 - core kernel

 - procfs

 - some of lib/ (lots of lib/ material this time)

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (104 commits)
  lib/lcm.c: replace include
  lib/percpu_ida.c: remove redundant includes
  lib/strncpy_from_user.c: replace module.h include
  lib/stmp_device.c: replace module.h include
  lib/sort.c: move include inside #if 0
  lib/show_mem.c: remove redundant include
  lib/radix-tree.c: change to simpler include
  lib/plist.c: remove redundant include
  lib/nlattr.c: remove redundant include
  lib/kobject_uevent.c: remove redundant include
  lib/llist.c: remove redundant include
  lib/md5.c: simplify include
  lib/list_sort.c: rearrange includes
  lib/genalloc.c: remove redundant include
  lib/idr.c: remove redundant include
  lib/halfmd4.c: simplify includes
  lib/dynamic_queue_limits.c: simplify includes
  lib/sort.c: use simpler includes
  lib/interval_tree.c: simplify includes
  hexdump: make it return number of bytes placed in buffer
  ...

lib/lcm.c: replace include

We don't need all the stuff kernel.h pulls in; just compiler.h since
export.h doesn't do necessary #includes.  This removes more than 100
dependencies.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/percpu_ida.c: remove redundant includes

These three #includes seem to be completely redundant: Removing them
yields identical objdump -d output for each of {allyes,allno,def}config,
and neither included file end up in the generated dependency file through
some recursive include.  In total, about 50 lines are eliminated from
.percpu.o.cmd.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/strncpy_from_user.c: replace module.h include

strncpy_from_user.c only needs EXPORT_SYMBOL, so just include compiler.h
and export.h instead of the whole module.h machinery.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/stmp_device.c: replace module.h include

stmp_device.c only needs EXPORT_SYMBOL, so just include compiler.h and
export.h instead of the whole module.h machinery.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/sort.c: move include inside #if 0

The sort function and its helpers don't do memory allocation, so the
slab.h include is redundant.  Move it inside the #if 0 protecting the
self-test, similar to how it is done in lib/list_sort.c.  This removes
over 450 lines from the generated dependency file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/show_mem.c: remove redundant include

show_mem.c doesn't use anything from nmi.h.  Removing it yields identical
objdump -d output for each of {allyes,allno,def}config and eliminates more
than 100 lines in the dependency file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/radix-tree.c: change to simpler include

The comment helpfully explains why hardirq.h is included, but since
commit 2d4b84739f0a ("hardirq: Split preempt count mask definitions")
in_interrupt() has been provided by preempt_mask.h.  Use that instead,
saving around 40 lines in the generated dependency file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/plist.c: remove redundant include

Removing the include of linux/spinlock.h produces byte-identical output
for {allno,def}config, and identical objdump -d output for allyesconfig.
In the former two cases, more than a 100 lines are eliminated from the
generated dependency file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/nlattr.c: remove redundant include

nlattr.c doesn't seem to rely on anything from netdevice.h.  Removing it
yields identical objdump -d output for each of {allyes,allno,def}config,
and eliminates more than 200 lines from the generated dependency file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/kobject_uevent.c: remove redundant include

The file doesn't seem to use anything from linux/user_namespace.h, and
removing it yields byte-identical object code and strictly fewer
dependencies in the .cmd file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/llist.c: remove redundant include

This file doesn't seem to use anything provided by linux/interrupt.h or
anything recursively included through that.  Removing it produces
byte-identical output, while reducing .llist.o.cmd from 541 to 156 lines.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/md5.c: simplify include

md5.c doesn't use anything from kernel.h, except that that pulls in
compiler.h, which is needed for the export.h to work.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/list_sort.c: rearrange includes

Memory allocation only happens in the self test, just as random numbers
are only used there.  So move the inclusion of slab.h inside the
CONFIG_TEST_LIST_SORT.

We don't need module.h and all of the stuff it carries with it, so replace
with export.h and compiler.h.  Unfortunately, the ARRAY_SIZE macro from
kernel.h requires the user to ensure bug.h is also included (for
BUILD_BUG_ON_ZERO, used by __must_be_array).  We used to get that through
some maze of nested includes, but just include it explicitly.

linux/string.h is then only included implicitly through
kernel.h->printk.h->dynamic_debug.h, but only if !CONFIG_DYNAMIC_DEBUG, so
just include it explicitly (for memset).

objdump -d says the generated code is the same, and wc -l says that
lib/.list_sort.o.cmd went from 579 to 165 lines.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/genalloc.c: remove redundant include

Removing this include produces byte-identical output, and thus removes a
false dependency.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/idr.c: remove redundant include

idr.c doesn't seem to use anything from hardirq.h (or anything included
from that).  Removing it produces identical objdump -d output, and gives
44 fewer lines in the .idr.o.cmd dependency file.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/halfmd4.c: simplify includes

We only need EXPORT_SYMBOL, so compiler.h and export.h suffice.  This
means linux/types.h is no longer implicitly included, so add an include of
uapi/linux/types.h to linux/cryptohash.h for __u32.  Other users of
cryptohash.h cannot be affected, since they must already have been
including uapi/linux/types.h in order for gcc not to complain about
unknown types.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/dynamic_queue_limits.c: simplify includes

The file doesn't use anything from ctype.h.  Instead of module.h, just use
export.h for EXPORT_SYMBOL.  The latter requires the user to include
compiler.h, so do that explicitly instead of relying on some other header
pulling it in.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/sort.c: use simpler includes

sort.c doesn't use facilities from kernel.h, but does use some types
defined in linux/types.h.  Include the latter directly instead of relying
on some other header doing it.  Similarly, include linux/export.h directly
instead of through module.h.  This removes 80 lines from the dependency
file .sort.o.cmd.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/interval_tree.c: simplify includes

The file uses nothing from init.h, and also doesn't need the full module.h
machinery; export.h is sufficient.  The latter requires the user to ensure
compiler.h is included, so do that explicitly instead of relying on some
other header pulling it in.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hexdump: make it return number of bytes placed in buffer

This patch makes hexdump return the number of bytes placed in the buffer
excluding trailing NUL.  In the case of overflow it returns the desired
amount of bytes to produce the entire dump.  Thus, it mimics snprintf().

This will be useful for users that would like to repeat with a bigger
buffer.

[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hexdump: do a few calculations ahead

Instead of doing calculations in each case of different groupsize let's do
them beforehand.  While there, change the switch to an if-else-if
construction.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hexdump: fix ascii column for the tail of a dump

In the current implementation we have a floating ascii column in the tail
of the dump.

For example, for row size equal to 16 the ascii column as in following
table

group size \ length 8 12 16
1 50 50 50
2 22 32 42
4 20 29 38
8 19 - 36

This patch makes it the same independently of amount of bytes dumped.

The change is safe since all current users, which use ASCII part of the
dump, rely on the group size equal to 1.  The patch doesn't change
behaviour for such group size (see the table above).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hexdump: introduce test suite

Test different scenarios of function calls located in lib/hexdump.c.

Currently hex_dump_to_buffer() is only tested and test data is provided
for little endian CPUs.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/genalloc.c: fix the end addr check in addr_in_gen_pool()

Since chunk->end_addr is (chunk->start_addr + size - 1), the end address
to compare should be (start + size - 1).

Signed-off-by: Toshi Kikuchi <toshik@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/string.c: remove strnicmp()

Now that all in-tree users of strnicmp have been converted to
strncasecmp, the wrapper can be removed.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: David Howells <dhowells@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: make the bits parameter of bitmap_remap unsigned

Also, rename bits to nbits. Both changes for consistency with other
bitmap_* functions.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: simplify bitmap_ord_to_pos

Make the return value and the ord and nbits parameters of
bitmap_ord_to_pos unsigned.

Also, simplify the implementation and as a side effect make the result
fully defined, returning nbits for ord >= weight, in analogy with what
find_{first,next}_bit does.  This is a better sentinel than the former
("unofficial") 0.  No current users are affected by this change.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: simplify bitmap_pos_to_ord

The ordinal of a set bit is simply the number of set bits before it;
counting those doesn't need to be done one bit at a time.  While at it,
update the parameters to unsigned int.

It is not completely unthinkable that gcc would see pos as compile-time
constant 0 in one of the uses of bitmap_pos_to_ord.  Since the static
inline frontend bitmap_weight doesn't handle nbits==0 correctly (it would
behave exactly as if nbits==BITS_PER_LONG), use __bitmap_weight.

Alternatively, the last line could be spelled bitmap_weight(buf, pos+1)-1,
but this is simpler.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: change parameters of bitmap_fold to unsigned

Change the sz and nbits parameters of bitmap_fold to unsigned int for
consistency with other bitmap_* functions, and to save another few bytes
in the generated code.

[akpm@linux-foundation.org: fix kerneldoc]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: update bitmap_onto to unsigned

Change the nbits parameter of bitmap_onto to unsigned int for consistency
with other bitmap_* functions.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

linux/cpumask.h: update bitmap wrappers to take unsigned int

Since the various bitmap_* functions now take an unsigned int as nbits
parameter, it makes sense to also update the various wrappers, even though
they're marked as obsolete.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

linux/nodemask.h: update bitmap wrappers to take unsigned int

Since the various bitmap_* functions now take an unsigned int as nbits
parameter, it makes sense to also update the various wrappers.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c: more signed->unsigned conversions

For consistency with the other bitmap_* functions, also make the nbits
parameter of bitmap_zero, bitmap_fill and bitmap_copy unsigned.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

libstring_helpers.c:string_get_size(): return void

string_get_size() was documented to return an error, but in fact always
returned 0.  Since the output always fits in 9 bytes, just document that
and let callers do what they do now: pass a small stack buffer and ignore
the return value.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/string_helpers.c:string_get_size(): use 32 bit arithmetic when possible

The remainder from do_div is always a u32, and after size has been reduced
to be below 1000 (or 1024), it certainly fits in u32.  So both remainder
and sf_cap can be made u32s, the format specifiers can be simplified (%lld
wasn't the right thing to use for _unsigned_ long long anyway), and we can
replace a do_div with an ordinary 32/32 bit division.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/string_helpers.c:string_get_size(): remove redundant prefixes

While commit 3c9f3681d0b4 ("[SCSI] lib: add generic helper to print
sizes rounded to the correct SI range") says that Z and Y are included
in preparation for 128 bit computers, they just waste .text currently.
If and when we get u128, string_get_size needs updating anyway (and ISO
needs to come up with four more prefixes).

Also there's no need to include and test for the NULL sentinel; once we
reach "E" size is at most 18.  [The test is also wrong; it should be
units_str[units][i+1]; if we've reached NULL we're already doomed.]

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/vsprintf.c: replace while with do-while in skip_atoi

All callers of skip_atoi have already checked for the first character
being a digit.  In this case, gcc generates simpler code for a do
while-loop.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/vsprintf.c: improve sanity check in vsnprintf()

On 64 bit, size may very well be huge even if bit 31 happens to be 0.
Somehow it doesn't feel right that one can pass a 5 GiB buffer but not a
3 GiB one.  So cap at INT_MAX as was probably the intention all along.
This is also the made-up value passed by sprintf and vsprintf.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/vsprintf.c: consume 'p' in format_decode

It seems a little simpler to consume the p from a %p specifier in
format_decode, just as it is done for the surrounding %c, %s and %% cases.

While there, delete a redundant and misplaced comment.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk: correct timeout comment, neaten MODULE_PARM_DESC

Neaten the MODULE_PARAM_DESC message.
Use 30 seconds in the comment for the zap console locks timeout.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel.h: remove ancient __FUNCTION__ hack

__FUNCTION__ hasn't been treated as a string literal since gcc 3.4, so
this only helps people who only test-compile using 3.3 (compiler-gcc3.h
barks at anything older than that).  Besides, there are almost no
occurrences of __FUNCTION__ left in the tree.

[akpm@linux-foundation.org: convert remaining __FUNCTION__ references]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

powerpc: add running_clock for powerpc to prevent spurious softlockup warnings

On POWER8 virtualised kernels the VTB register can be read to have a view
of time that only increases while the guest is running.  This will prevent
guests from seeing time jump if a guest is paused for significant amounts
of time.

On POWER7 and below virtualised kernels stolen time is subtracted from
local_clock as a best effort approximation.  This will not eliminate
spurious warnings in the case of a suspended guest but may reduce the
occurance in the case of softlockups due to host over commit.

Bare metal kernels should avoid reading the VTB as KVM does not restore
sane values when not executing, the approxmation is fine as host kernels
won't observe any stolen time.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrew Jones <drjones@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: chai wen <chaiw.fnst@cn.fujitsu.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Ben Zhang <benzh@chromium.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/sched/clock.c: add another clock for use with the soft lockup watchdog

When the hypervisor pauses a virtualised kernel the kernel will observe a
jump in timebase, this can cause spurious messages from the softlockup
detector.

Whilst these messages are harmless, they are accompanied with a stack
trace which causes undue concern and more problematically the stack trace
in the guest has nothing to do with the observed problem and can only be
misleading.

Futhermore, on POWER8 this is completely avoidable with the introduction
of the Virtual Time Base (VTB) register.

This patch (of 2):

This permits the use of arch specific clocks for which virtualised kernels
can use their notion of 'running' time, not the elpased wall time which
will include host execution time.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrew Jones <drjones@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: chai wen <chaiw.fnst@cn.fujitsu.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Ben Zhang <benzh@chromium.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

linux/types.h: Always use unsigned long for pgoff_t

Everybody uses unsigned long for pgoff_t, and no one ever overrode the
definition of pgoff_t.  Keep it that way, and remove the option of
overriding it.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

gitignore: ignore tar-install build directory

Have git ignore the Debian directory created when running:
     make tar-pkg / targz-pkg / tarbz2-pkg / tarxz-pkg

Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

all arches, signal: move restart_block to struct task_struct

If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target.  This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: Richard Weinberger <richard@nod.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/array.c: convert to use string_escape_str()

Instead of custom approach let's use string_escape_str() to escape a given
string (task_name in this case).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: proc: task_mmu: show page size in /proc/<pid>/numa_maps

The output of /proc/$pid/numa_maps is in terms of number of pages like
anon=22 or dirty=54.  Here's some output:

  7f4680000000 default file=/hugetlb/bigfile anon=50 dirty=50 N0=50
  7f7659600000 default file=/anon_hugepage\040(deleted) anon=50 dirty=50 N0=50
  7fff8d425000 default stack anon=50 dirty=50 N0=50

Looks like we have a stack and a couple of anonymous hugetlbfs
areas page which both use the same amount of memory.  They don't.

The 'bigfile' uses 1GB pages and takes up ~50GB of space.  The
anon_hugepage uses 2MB pages and takes up ~100MB of space while the stack
uses normal 4k pages.  You can go over to smaps to figure out what the
page size _really_ is with KernelPageSize or MMUPageSize.  But, I think
this is a pretty nasty and counterintuitive interface as it stands.

This patch introduces 'kernelpagesize_kB' line element to
/proc/<pid>/numa_maps report file in order to help identifying the size of
pages that are backing memory areas mapped by a given task.  This is
specially useful to help differentiating between HUGE and GIGANTIC page
backed VMAs.

This patch is based on Dave Hansen's proposal and reviewer's follow-ups
taken from the following dicussion threads:
 * https://lkml.org/lkml/2011/9/21/454
 * https://lkml.org/lkml/2014/12/20/66

Signed-off-by: Rafael Aquini <aquini@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/proc.txt: add /proc/pid/numa_maps interface explanation snippet

Add a small section to proc.txt doc in order to document its
/proc/pid/numa_maps interface.  It does not introduce any functional
changes, just documentation.

Signed-off-by: Rafael Aquini <aquini@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: proc: use PDE() to get proc_dir_entry

Use the PDE() helper to get proc_dir_entry instead of coding it directly.

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/task_mmu.c: add user-space support for resetting mm->hiwater_rss (peak RSS)

Peak resident size of a process can be reset back to the process's
current rss value by writing "5" to /proc/pid/clear_refs.  The driving
use-case for this would be getting the peak RSS value, which can be
retrieved from the VmHWM field in /proc/pid/status, per benchmark
iteration or test scenario.

[akpm@linux-foundation.org: clarify behaviour in documentation]
Signed-off-by: Petr Cermak <petrcermak@chromium.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Primiano Tucci <primiano@chromium.org>
Cc: Petr Cermak <petrcermak@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/frv/mm/extable.c: remove unused function

Remove the function search_one_table() that is not used anywhere.

This was partially found by using a static code analysis program called
cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/zsmalloc: add statistics support

Keeping fragmentation of zsmalloc in a low level is our target.  But now
we still need to add the debug code in zsmalloc to get the quantitative
data.

This patch adds a new configuration CONFIG_ZSMALLOC_STAT to enable the
statistics collection for developers.  Currently only the objects
statatitics in each class are collected.  User can get the information via
debugfs.

     cat /sys/kernel/debug/zsmalloc/zram0/...

For example:

After I copied "jdk-8u25-linux-x64.tar.gz" to zram with ext4 filesystem:
 class  size obj_allocated   obj_used pages_used
     0    32             0          0          0
     1    48           256         12          3
     2    64            64         14          1
     3    80            51          7          1
     4    96           128          5          3
     5   112            73          5          2
     6   128            32          4          1
     7   144             0          0          0
     8   160             0          0          0
     9   176             0          0          0
    10   192             0          0          0
    11   208             0          0          0
    12   224             0          0          0
    13   240             0          0          0
    14   256            16          1          1
    15   272            15          9          1
    16   288             0          0          0
    17   304             0          0          0
    18   320             0          0          0
    19   336             0          0          0
    20   352             0          0          0
    21   368             0          0          0
    22   384             0          0          0
    23   400             0          0          0
    24   416             0          0          0
    25   432             0          0          0
    26   448             0          0          0
    27   464             0          0          0
    28   480             0          0          0
    29   496            33          1          4
    30   512             0          0          0
    31   528             0          0          0
    32   544             0          0          0
    33   560             0          0          0
    34   576             0          0          0
    35   592             0          0          0
    36   608             0          0          0
    37   624             0          0          0
    38   640             0          0          0
    40   672             0          0          0
    42   704             0          0          0
    43   720            17          1          3
    44   736             0          0          0
    46   768             0          0          0
    49   816             0          0          0
    51   848             0          0          0
    52   864            14          1          3
    54   896             0          0          0
    57   944            13          1          3
    58   960             0          0          0
    62  1024             4          1          1
    66  1088            15          2          4
    67  1104             0          0          0
    71  1168             0          0          0
    74  1216             0          0          0
    76  1248             0          0          0
    83  1360             3          1          1
    91  1488            11          1          4
    94  1536             0          0          0
   100  1632             5          1          2
   107  1744             0          0          0
   111  1808             9          1          4
   126  2048             4          4          2
   144  2336             7          3          4
   151  2448             0          0          0
   168  2720            15         15         10
   190  3072            28         27         21
   202  3264             0          0          0
   254  4096         36209      36209      36209

 Total               37022      36326      36288

We can calculate the overall fragentation by the last line:
    Total               37022      36326      36288
    (37022 - 36326) / 37022 = 1.87%

Also by analysing objects alocated in every class we know why we got so
low fragmentation: Most of the allocated objects is in <class 254>.  And
there is only 1 page in class 254 zspage.  So, No fragmentation will be
introduced by allocating objs in class 254.

And in future, we can collect other zsmalloc statistics as we need and
analyse them.

Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Suggested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/zpool: add name argument to create zpool

Currently the underlay of zpool: zsmalloc/zbud, do not know who creates
them.  There is not a method to let zsmalloc/zbud find which caller they
belong to.

Now we want to add statistics collection in zsmalloc.  We need to name the
debugfs dir for each pool created.  The way suggested by Minchan Kim is to
use a name passed by caller(such as zram) to create the zsmalloc pool.

    /sys/kernel/debug/zsmalloc/zram0

This patch adds an argument `name' to zs_create_pool() and other related
functions.

Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zram: remove request_queue from struct zram

`struct zram' contains both `struct gendisk' and `struct request_queue'.
the latter can be deleted, because zram->disk carries ->queue pointer, and
->queue carries zram pointer:

create_device()
zram->queue->queuedata = zram
zram->disk->queue = zram->queue
zram->disk->private_data = zram

so zram->queue is not needed, we can access all necessary data anyway.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zram: remove init_lock in zram_make_request

Admin could reset zram during I/O operation going on so we have used
zram->init_lock as read-side lock in I/O path to prevent sudden zram
meta freeing.

However, the init_lock is really troublesome.  We can't do call
zram_meta_alloc under init_lock due to lockdep splat because
zram_rw_page is one of the function under reclaim path and hold it as
read_lock while other places in process context hold it as write_lock.
So, we have used allocation out of the lock to avoid lockdep warn but
it's not good for readability and fainally, I met another lockdep splat
between init_lock and cpu_hotplug from kmem_cache_destroy during working
zsmalloc compaction.  :(

Yes, the ideal is to remove horrible init_lock of zram in rw path.  This
patch removes it in rw path and instead, add atomic refcount for meta
lifetime management and completion to free meta in process context.
It's important to free meta in process context because some of resource
destruction needs mutex lock, which could be held if we releases the
resource in reclaim context so it's deadlock, again.

As a bonus, we could remove init_done check in rw path because
zram_meta_get will do a role for it, instead.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zram: check bd_openers instead of bd_holders

bd_holders is increased only when user open the device file as FMODE_EXCL
so if something opens zram0 as !FMODE_EXCL and request I/O while another
user reset zram0, we can see following warning.

  zram0: detected capacity change from 0 to 64424509440
  Buffer I/O error on dev zram0, logical block 180823, lost async page write
  Buffer I/O error on dev zram0, logical block 180824, lost async page write
  Buffer I/O error on dev zram0, logical block 180825, lost async page write
  Buffer I/O error on dev zram0, logical block 180826, lost async page write
  Buffer I/O error on dev zram0, logical block 180827, lost async page write
  Buffer I/O error on dev zram0, logical block 180828, lost async page write
  Buffer I/O error on dev zram0, logical block 180829, lost async page write
  Buffer I/O error on dev zram0, logical block 180830, lost async page write
  Buffer I/O error on dev zram0, logical block 180831, lost async page write
  Buffer I/O error on dev zram0, logical block 180832, lost async page write
  ------------[ cut here ]------------
  WARNING: CPU: 11 PID: 1996 at fs/block_dev.c:57 __blkdev_put+0x1d7/0x210()
  Modules linked in:
  CPU: 11 PID: 1996 Comm: dd Not tainted 3.19.0-rc6-next-20150202+ #1125
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
    dump_stack+0x45/0x57
    warn_slowpath_common+0x8a/0xc0
    warn_slowpath_null+0x1a/0x20
    __blkdev_put+0x1d7/0x210
    blkdev_put+0x50/0x130
    blkdev_close+0x25/0x30
    __fput+0xdf/0x1e0
    ____fput+0xe/0x10
    task_work_run+0xa7/0xe0
    do_notify_resume+0x49/0x60
    int_signal+0x12/0x17
  ---[ end trace 274fbbc5664827d2 ]---

The warning comes from bdev_write_node in blkdev_put path.

   static void bdev_write_inode(struct inode *inode)
   {
        spin_lock(&inode->i_lock);
        while (inode->i_state & I_DIRTY) {
                spin_unlock(&inode->i_lock);
                WARN_ON_ONCE(write_inode_now(inode, true)); <========= here.
                spin_lock(&inode->i_lock);
        }
        spin_unlock(&inode->i_lock);
   }

The reason is dd process encounters I/O fails due to sudden block device
disappear so in filemap_check_errors in __writeback_single_inode returns
-EIO.

If we check bd_openers instead of bd_holders, we could address the
problem.  When I see the brd, it already have used it rather than
bd_holders so although I'm not a expert of block layer, it seems to be
better.

I can make following warning with below simple script.  In addition, I
added msleep(2000) below set_capacity(zram->disk, 0) after applying your
patch to make window huge(Kudos to Ganesh!)

script:

   echo $((60<<30)) > /sys/block/zram0/disksize
   setsid dd if=/dev/zero of=/dev/zram0 &
   sleep 1
   setsid echo 1 > /sys/block/zram0/reset

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zram: rework reset and destroy path

We need to return set_capacity(disk, 0) from reset_store() back to
zram_reset_device(), a catch by Ganesh Mahendran.  Potentially, we can
race set_capacity() calls from init and reset paths.

The problem is that zram_reset_device() is also getting called from
zram_exit(), which performs operations in misleading reversed order -- we
first create_device() and then init it, while zram_exit() perform
destroy_device() first and then does zram_reset_device().  This is done to
remove sysfs group before we reset device, so we can continue with device
reset/destruction not being raced by sysfs attr write (f.e.  disksize).

Apart from that, destroy_device() releases zram->disk (but we still have
->disk pointer), so we cannot acces zram->disk in later
zram_reset_device() call, which may cause additional errors in the future.

So, this patch rework and cleanup destroy path.

1) remove several unneeded goto labels in zram_init()

2) factor out zram_init() error path and zram_exit() into
   destroy_devices() function, which takes the number of devices to
   destroy as its argument.

3) remove sysfs group in destroy_devices() first, so we can reorder
   operations -- reset device (as expected) goes before disk destroy and
   queue cleanup.  So we can always access ->disk in zram_reset_device().

4) and, finally, return set_capacity() back under ->init_lock.

[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zram: fix umount-reset_store-mount race condition

Ganesh Mahendran was the first one who proposed to use bdev->bd_mutex to
avoid ->bd_holders race condition:

        CPU0                            CPU1
umount /* zram->init_done is true */
reset_store()
bdev->bd_holders == 0                   mount
...                                     zram_make_request()
zram_reset_device()

However, his solution required some considerable amount of code movement,
which we can avoid.

Apart from using bdev->bd_mutex in reset_store(), this patch also
simplifies zram_reset_device().

zram_reset_device() has a bool parameter reset_capacity which tells it
whether disk capacity and itself disk should be reset.  There are two
zram_reset_device() callers:

-- zram_exit() passes reset_capacity=false
-- reset_store() passes reset_capacity=true

So we can move reset_capacity-sensitive work out of zram_reset_device()
and perform it unconditionally in reset_store().  This also lets us drop
reset_capacity parameter from zram_reset_device() and pass zram pointer
only.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zram: free meta table in zram_meta_free

zram_meta_alloc() and zram_meta_free() are a pair.  In
zram_meta_alloc(), meta table is allocated.  So it it better to free it
in zram_meta_free().

Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zram: clean up zram_meta_alloc()

A trivial cleanup of zram_meta_alloc() error handling.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: fix negative nr_isolated counts

The vmstat interfaces are good at hiding negative counts (at least when
CONFIG_SMP); but if you peer behind the curtain, you find that
nr_isolated_anon and nr_isolated_file soon go negative, and grow ever
more negative: so they can absorb larger and larger numbers of isolated
pages, yet still appear to be zero.

I'm happy to avoid a congestion_wait() when too_many_isolated() myself;
but I guess it's there for a good reason, in which case we ought to get
too_many_isolated() working again.

The imbalance comes from isolate_migratepages()'s ISOLATE_ABORT case:
putback_movable_pages() decrements the NR_ISOLATED counts, but we forgot
to call acct_isolated() to increment them.

It is possible that the bug whcih this patch fixes could cause OOM kills
when the system still has a lot of reclaimable page cache.

Fixes: edc2ca612496 ("mm, compaction: move pageblock checks up from isolate_migratepages_range()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org> [3.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page()

A race condition starts to be visible in recent mmotm, where a PG_hwpoison
flag is set on a migration source page *before* it's back in buddy page
poo= l.

This is problematic because no page flag is supposed to be set when
freeing (see __free_one_page().) So the user-visible effect of this race
is that it could trigger the BUG_ON() when soft-offlining is called.

The root cause is that we call lru_add_drain_all() to make sure that the
page is in buddy, but that doesn't work because this function just
schedule= s a work item and doesn't wait its completion.
drain_all_pages() does drainin= g directly, so simply dropping
lru_add_drain_all() solves this problem.

Fixes: f15bdfa802bf ("mm/memory-failure.c: fix memory leak in successful soft offlining")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: <stable@vger.kernel.org> [3.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc: fix comment

Add a necessary 'leave'.

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory.c: actually remap enough memory

For whatever reason, generic_access_phys() only remaps one page, but
actually allows to access arbitrary size.  It's quite easy to trigger
large reads, like printing out large structure with gdb, which leads to a
crash.  Fix it by remapping correct size.

Fixes: 28b2ee20c7cb ("access_process_vm device memory infrastructure")
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/cpuset.c: Mark cpuset_init_current_mems_allowed as __init

The only caller of cpuset_init_current_mems_allowed is the __init
annotated build_all_zonelists_init, so we can also make the former __init.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Cc: Pintu Kumar <pintu.k@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mm_init.c: mark mminit_loglevel __meminitdata

mminit_loglevel is only referenced from __init and __meminit functions, so
we can mark it __meminitdata.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Cc: Pintu Kumar <pintu.k@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mm_init.c: park mminit_verify_zonelist as __init

The only caller of mminit_verify_zonelist is build_all_zonelists_init,
which is annotated with __init, so it should be safe to also mark the
former as __init, saving ~400 bytes of .text.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Cc: Pintu Kumar <pintu.k@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c: pull out init code from build_all_zonelists

Pulling the code protected by if (system_state == SYSTEM_BOOTING) into
its own helper allows us to shrink .text a little. This relies on
build_all_zonelists already having a __ref annotation. Add a comment
explaining why so one doesn't have to track it down through git log.

The real saving comes in 3/5, ("mm/mm_init.c: Mark mminit_verify_zonelist
as __init"), where we save about 400 bytes

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Cc: Pintu Kumar <pintu.k@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/internal.h: don't split printk call in two

All users of mminit_dprintk pass a compile-time constant as level, so this
just makes gcc emit a single printk call instead of two.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vishnu Pratap Singh <vishnu.ps@samsung.com>
Cc: Pintu Kumar <pintu.k@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: do not use mm->nr_pmds on !MMU configurations

mm->nr_pmds doesn't make sense on !MMU configurations

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>