diff options
| author | Ming Lei <ming.lei@redhat.com> | 2022-04-20 22:31:10 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-05-02 10:07:42 -0600 |
| commit | 9650b453a3d4b1b8ed4ea8bcb9b40109608d1faf (patch) | |
| tree | c43dfc5033aec249e22536898a6a043390df7782 /fs/iomap | |
| parent | e233fe1aa02815f38588a5a965a197bbcabfb125 (diff) | |
| download | linux-9650b453a3d4b1b8ed4ea8bcb9b40109608d1faf.tar.gz | |
block: ignore RWF_HIPRI hint for sync dio
So far bio is marked as REQ_POLLED if RWF_HIPRI/IOCB_HIPRI is passed
from userspace sync io interface, then block layer tries to poll until
the bio is completed. But the current implementation calls
blk_io_schedule() if bio_poll() returns 0, and this way causes io hang or
timeout easily.
But looks no one reports this kind of issue, which should have been
triggered in normal io poll sanity test or blktests block/007 as
observed by Changhui, that means it is very likely that no one uses it
or no one cares it.
Also after io_uring is invented, io poll for sync dio becomes legacy
interface.
So ignore RWF_HIPRI hint for sync dio.
CC: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Reported-by: Changhui Zhong <czhong@redhat.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Changhui Zhong <czhong@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220420143110.2679002-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/iomap')
| -rw-r--r-- | fs/iomap/direct-io.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 62da020d02a11..80f9b047aa1b6 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -56,7 +56,8 @@ static void iomap_dio_submit_bio(const struct iomap_iter *iter, { atomic_inc(&dio->ref); - if (dio->iocb->ki_flags & IOCB_HIPRI) { + /* Sync dio can't be polled reliably */ + if ((dio->iocb->ki_flags & IOCB_HIPRI) && !is_sync_kiocb(dio->iocb)) { bio_set_polled(bio, dio->iocb); dio->submit.poll_bio = bio; } @@ -653,9 +654,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (!READ_ONCE(dio->submit.waiter)) break; - if (!dio->submit.poll_bio || - !bio_poll(dio->submit.poll_bio, NULL, 0)) - blk_io_schedule(); + blk_io_schedule(); } __set_current_state(TASK_RUNNING); } |