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 /arch/x86/mm/fault.c | |
| parent | 4ffeaf3560a52b4a69cc7909873d08c0ef5909d4 (diff) | |
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 'arch/x86/mm/fault.c')
| -rw-r--r-- | arch/x86/mm/fault.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 1dbade870f90..a24194681513 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1218,7 +1218,8 @@ good_area: /* * If for any reason at all we couldn't handle the fault, * make sure we exit gracefully rather than endlessly redo - * the fault: + * the fault. Since we never set FAULT_FLAG_RETRY_NOWAIT, if + * we get VM_FAULT_RETRY back, the mmap_sem has been unlocked. */ fault = handle_mm_fault(mm, vma, address, flags); |