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block: don't try to poll multi-bio I/Os in __blkdev_direct_IO 

If an iocb is split into multiple bios we can't poll for both.  So don't
even bother to try to poll in that case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211012111226.760968-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2021-10-12 13:12:12 +02:00 committed by Jens Axboe
parent 94c2ed58d0
commit 71fc3f5e2c
1 changed files with 7 additions and 14 deletions
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21
block/fops.c
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@ -197,7 +197,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
struct blk_plug plug;
struct blkdev_dio *dio;
struct bio *bio;
bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
bool do_poll = (iocb->ki_flags & IOCB_HIPRI);
bool is_read = (iov_iter_rw(iter) == READ), is_sync;
loff_t pos = iocb->ki_pos;
blk_qc_t qc = BLK_QC_T_NONE;
@ -226,7 +226,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
* Don't plug for HIPRI/polled IO, as those should go straight
* to issue
*/
if (!is_poll)
if (!(iocb->ki_flags & IOCB_HIPRI))
blk_start_plug(&plug);
for (;;) {
@ -260,20 +260,13 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
if (!nr_pages) {
bool polled = false;
if (iocb->ki_flags & IOCB_HIPRI) {
if (do_poll)
bio_set_polled(bio, iocb);
polled = true;
}
qc = submit_bio(bio);
if (polled)
if (do_poll)
WRITE_ONCE(iocb->ki_cookie, qc);
break;
}
if (!dio->multi_bio) {
/*
* AIO needs an extra reference to ensure the dio
@ -284,6 +277,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
bio_get(bio);
dio->multi_bio = true;
atomic_set(&dio->ref, 2);
do_poll = false;
} else {
atomic_inc(&dio->ref);
}
@ -292,7 +286,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
bio = bio_alloc(GFP_KERNEL, nr_pages);
}
if (!is_poll)
if (!(iocb->ki_flags & IOCB_HIPRI))
blk_finish_plug(&plug);
if (!is_sync)
@ -303,8 +297,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
if (!READ_ONCE(dio->waiter))
break;
if (!(iocb->ki_flags & IOCB_HIPRI) ||
!blk_poll(bdev_get_queue(bdev), qc, true))
if (!do_poll || !blk_poll(bdev_get_queue(bdev), qc, true))
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);