tree 1c8490271a6cffa9b43858e0f29d6ddab0122fac
parent 79da5407eeadc740fbf4b45d6df7d7f8e6adaf2c
author Kirill A. Shutemov <kirill.shutemov@linux.intel.com> 1355349074 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1355362712 -0800

thp: avoid race on multiple parallel page faults to the same page

pmd value is stable only with mm->page_table_lock taken. After taking
the lock we need to check that nobody modified the pmd before changing it.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Reviewed-by: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>