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| 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 62da020d02a1..80f9b047aa1b 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); } |