diff options
| author |   Nikita Ermakov <sh1r4s3@mail.si-head.nl> | 2021-04-29 22:55:41 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-30 11:20:37 -0700 |
| commit | f6899bc03cbadc6e308d98252c4a832b5fd45b87 (patch) | |
| tree | 047f88de9d3090eda8dd6ef962c4c8cf95c09aae /mm/msync.c | |
| parent | mm/filemap: update stale comment (diff) | |
| download | linux-dev-f6899bc03cbadc6e308d98252c4a832b5fd45b87.tar.xz linux-dev-f6899bc03cbadc6e308d98252c4a832b5fd45b87.zip | |
mm/msync: exit early when the flags is an MS_ASYNC and start < vm_start
If an unmapped region was found and the flag is MS_ASYNC (without
MS_INVALIDATE) there is nothing to do and the result would be always
-ENOMEM, so return immediately.
Link: https://lkml.kernel.org/r/20201025092901.56399-1-sh1r4s3@mail.si-head.nl
Signed-off-by: Nikita Ermakov <sh1r4s3@mail.si-head.nl>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/msync.c')
| -rw-r--r-- | mm/msync.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/msync.c b/mm/msync.c index 69c6d2029531..137d1c104f3e 100644 --- a/mm/msync.c +++ b/mm/msync.c @@ -55,7 +55,9 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags) goto out; /* * If the interval [start,end) covers some unmapped address ranges, - * just ignore them, but return -ENOMEM at the end. + * just ignore them, but return -ENOMEM at the end. Besides, if the + * flag is MS_ASYNC (w/o MS_INVALIDATE) the result would be -ENOMEM + * anyway and there is nothing left to do, so return immediately. */ mmap_read_lock(mm); vma = find_vma(mm, start); @@ -69,6 +71,8 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags) goto out_unlock; /* Here start < vma->vm_end. */ if (start < vma->vm_start) { + if (flags == MS_ASYNC) + goto out_unlock; start = vma->vm_start; if (start >= end) goto out_unlock; |