dax: protect PTE modification on WP fault by radix tree entry lock
authorJan Kara <jack@suse.cz>
Wed, 14 Dec 2016 23:07:50 +0000 (15:07 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 15 Dec 2016 00:04:09 +0000 (16:04 -0800)
commit2f89dc12a25ddf995b9acd7b6543fe892e3473d6
treed162312aa8bdcb6602a9c30dd5810c0f2f8e0a16
parenta6abc2c0e77b16480f4d2c1eb7925e5287ae1526
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>
fs/dax.c
mm/memory.c