tree cbc6d973dbe88c0d397a62167bd5d3d66337ba40
parent d295e3415a88ae63a37a22652808b20c7fcb970e
author Matthew Wilcox <willy@linux.intel.com> 1441749577 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1441751728 -0700

dax: ensure that zero pages are removed from other processes

If the first access to a huge page was a store, there would be no existing
zero pmd in this process's page tables.  There could be a zero pmd in
another process's page tables, if it had done a load.  We can detect this
case by noticing that the buffer_head returned from the filesystem is New,
and ensure that other processes mapping this huge page have their page
tables flushed.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>