radix-tree: move rcu_head into a union with private_list
authorMatthew Wilcox <willy@infradead.org>
Wed, 14 Dec 2016 23:08:34 +0000 (15:08 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 15 Dec 2016 00:04:10 +0000 (16:04 -0800)
commit91d9c05ac6c788531136888d31ef18c6a0ec160f
tree858de508527dbe571ca87a77d572a38ebf92b55d
parent91b9677c4c1242a3d0afd76d0e91f43808243b92
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>
include/linux/radix-tree.h
lib/radix-tree.c