diff options
| author | Pavel Begunkov | 2021-02-24 12:01:45 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2021-02-24 13:38:27 -0800 |
| commit | ab2125df921d991a3c8a4fdcfe617ef6cad6b484 (patch) | |
| tree | 162a4f8e7c945d4ec69f8c5272ef1baee99a43d2 | |
| parent | 1f7ef657740344541645349a8bece90cbff898f5 (diff) | |
mm/filemap: don't revert iter on -EIOCBQUEUED
Currently, if I/O is enqueued for async execution direct paths of
generic_file_{read,write}_iter() will always revert the iter. There are
no users expecting that, and that is also costly. Leave iterators as is
on -EIOCBQUEUED.
Link: https://lkml.kernel.org/r/f5247b60e7abbd2ff850cd108491f53a2e0c501a.1610207781.git.asml.silence@gmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/filemap.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 7dfed3454a2e..774a869da106 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2615,7 +2615,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) iocb->ki_pos += retval; count -= retval; } - iov_iter_revert(iter, count - iov_iter_count(iter)); + if (retval != -EIOCBQUEUED) + iov_iter_revert(iter, count - iov_iter_count(iter)); /* * Btrfs can have a short DIO read if we encounter @@ -3426,7 +3427,8 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from) } iocb->ki_pos = pos; } - iov_iter_revert(from, write_len - iov_iter_count(from)); + if (written != -EIOCBQUEUED) + iov_iter_revert(from, write_len - iov_iter_count(from)); out: return written; } |