diff options
| author |   Paul Cassella <cassella@cray.com> | 2014-08-06 16:07:24 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-06 18:01:20 -0700 |
| commit | 9a95f3cf7b33d66fa64727cff8cd2f2a9d09f335 (patch) | |
| tree | 14d7c178144b6de0b352b8e8d4b04ffdbae9a71c /include | |
| parent | mm: page_alloc: reduce cost of the fair zone allocation policy (diff) | |
| download | linux-dev-9a95f3cf7b33d66fa64727cff8cd2f2a9d09f335.tar.xz linux-dev-9a95f3cf7b33d66fa64727cff8cd2f2a9d09f335.zip | |
mm: describe mmap_sem rules for __lock_page_or_retry() and callers
Add a comment describing the circumstances in which
__lock_page_or_retry() will or will not release the mmap_sem when
returning 0.
Add comments to lock_page_or_retry()'s callers (filemap_fault(),
do_swap_page()) noting the impact on VM_FAULT_RETRY returns.
Add comments on up the call tree, particularly replacing the false "We
return with mmap_sem still held" comments.
Signed-off-by: Paul Cassella <cassella@cray.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/pagemap.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index e1474ae18c88..3df8c7db7a4e 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -484,6 +484,9 @@ static inline int lock_page_killable(struct page *page) /* * lock_page_or_retry - Lock the page, unless this would block and the * caller indicated that it can handle a retry. + * + * Return value and mmap_sem implications depend on flags; see + * __lock_page_or_retry(). */ static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm, unsigned int flags) |