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block: check BLK_FEAT_POLL under q_usage_count

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Otherwise feature reconfiguration can race with I/O submission.

Also drop the bio_clear_polled in the error path, as the flag does not
matter for instant error completions, it is a left over from when we
allowed polled I/O to proceed unpolled in this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250110054726.1499538-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2025-01-10 06:47:11 +01:00 • committed by Jens Axboe
parent aa427d7b73
commit 958148a6ac
2 changed files with 22 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
block/blk-core.c
View file

@ -629,8 +629,14 @@ static void __submit_bio(struct bio *bio)
blk_mq_submit_bio(bio);
} else if (likely(bio_queue_enter(bio) == 0)) {
struct gendisk *disk = bio->bi_bdev->bd_disk;
disk->fops->submit_bio(bio);
if ((bio->bi_opf & REQ_POLLED) &&
!(disk->queue->limits.features & BLK_FEAT_POLL)) {
bio->bi_status = BLK_STS_NOTSUPP;
bio_endio(bio);
} else {
disk->fops->submit_bio(bio);
}
blk_queue_exit(disk->queue);
}
@ -805,12 +811,6 @@ void submit_bio_noacct(struct bio *bio)
}
}
if (!(q->limits.features & BLK_FEAT_POLL) &&
(bio->bi_opf & REQ_POLLED)) {
bio_clear_polled(bio);
goto not_supported;
}
switch (bio_op(bio)) {
case REQ_OP_READ:
break;
@ -935,7 +935,7 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
return 0;
q = bdev_get_queue(bdev);
if (cookie == BLK_QC_T_NONE || !(q->limits.features & BLK_FEAT_POLL))
if (cookie == BLK_QC_T_NONE)
return 0;
blk_flush_plug(current->plug, false);
@ -951,7 +951,9 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
*/
if (!percpu_ref_tryget(&q->q_usage_counter))
return 0;
if (queue_is_mq(q)) {
if (!(q->limits.features & BLK_FEAT_POLL)) {
ret = 0;
} else if (queue_is_mq(q)) {
ret = blk_mq_poll(q, cookie, iob, flags);
} else {
struct gendisk *disk = q->disk;

12
block/blk-mq.c
View file

@ -3096,14 +3096,22 @@ void blk_mq_submit_bio(struct bio *bio)
}
/*
* Device reconfiguration may change logical block size, so alignment
* check has to be done with queue usage counter held
* Device reconfiguration may change logical block size or reduce the
* number of poll queues, so the checks for alignment and poll support
* have to be done with queue usage counter held.
*/
if (unlikely(bio_unaligned(bio, q))) {
bio_io_error(bio);
goto queue_exit;
}
if ((bio->bi_opf & REQ_POLLED) &&
!(q->limits.features & BLK_FEAT_POLL)) {
bio->bi_status = BLK_STS_NOTSUPP;
bio_endio(bio);
goto queue_exit;
}
bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
if (!bio)
goto queue_exit;