On 5/23/25 10:10, Damien Le Moal wrote:
> What about this patch, completely untested...
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index e8cc270a453f..3d2dec088a54 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -621,6 +621,32 @@ static inline blk_status_t blk_check_zone_append(struct
> request_queue *q,
> return BLK_STS_OK;
> }
>
> +static inline void disk_submit_bio(struct bio *bio)
> +{
> + struct gendisk *disk = bio->bi_bdev->bd_disk;
> + bool need_queue_enter = !bio_zone_write_plugging(bio);
> +
> + /*
> + * BIOs that are issued from a zone write plug already hold a reference
> + * on the device queue usage counter.
> + */
> + if (need_queue_enter) {
> + if (unlikely(bio_queue_enter(bio)))
> + return;
> + }
> +
> + 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);
> + }
> +
> + if (need_queue_enter)
> + blk_queue_exit(disk->queue);
> +}
> +
> static void __submit_bio(struct bio *bio)
> {
> /* If plug is not used, add new plug here to cache nsecs time. */
> @@ -631,20 +657,10 @@ static void __submit_bio(struct bio *bio)
>
> blk_start_plug(&plug);
>
> - if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO)) {
> + if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO))
> blk_mq_submit_bio(bio);
> - } else if (likely(bio_queue_enter(bio) == 0)) {
> - struct gendisk *disk = bio->bi_bdev->bd_disk;
> -
> - 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);
> - }
> + else
> + disk_submit_bio(bio)
Missing ";" here.
>
> blk_finish_plug(&plug);
> }
Looking into this deeper, the regular mq path actually likely has the same issue
since it will call blk_queue_enter() if we do not have a cached request. So this
solution is only partial and not good enough. We need something else.
--
Damien Le Moal
Western Digital Research
