> index bf930f4..4c5952b 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
Can you split the block core changes into separate patches in a
series?
> @@ -2031,6 +2031,11 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
> should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
> return -EIO;
>
> + if (q->mq_ops) {
> + blk_mq_insert_request(rq, false, true, true);
> + return 0;
> + }
In the case of a torn down queue this one will complete the request,
while the !mq case will return an error. Does the upper level code
handle that difference fine?
> spin_lock_irqsave(q->queue_lock, flags);
> if (unlikely(blk_queue_dying(q))) {
> spin_unlock_irqrestore(q->queue_lock, flags);
> @@ -2928,8 +2933,6 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
> if (!bs)
> bs = fs_bio_set;
>
> - blk_rq_init(NULL, rq);
> -
Moving this into the caller in a preparatory patch would be useful, too.
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 383ea0c..eb53d1c 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -172,6 +172,7 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
> #if defined(CONFIG_BLK_DEV_INTEGRITY)
> rq->nr_integrity_segments = 0;
> #endif
> + rq->bio = NULL;
Jens has been trying to micro-optimize this area and avoid additional
overhead for the fast path. It would be better to do this in dm-mpath.
> unsigned long flags;
> struct pgpath *pgpath;
> struct block_device *bdev;
> @@ -410,9 +411,11 @@ static int multipath_map(struct dm_target *ti, struct request *clone,
> goto out_unlock;
>
> bdev = pgpath->path.dev->bdev;
> - clone->q = bdev_get_queue(bdev);
> - clone->rq_disk = bdev->bd_disk;
> - clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
> + *clone = blk_get_request(bdev_get_queue(bdev), rq_data_dir(rq),
> + GFP_KERNEL);
I suspect this should be GFP_NOWAIT so that we can push the request back
up the stack if none are available.
> + if (!(*clone))
> + goto out_unlock;
No need for the inner braces.
> * This may be used when the target's map_rq() function fails.
> */
> -void dm_kill_unmapped_request(struct request *clone, int error)
> +void dm_kill_unmapped_request(struct request *rq, int error)
> {
> - struct dm_rq_target_io *tio = clone->end_io_data;
> - struct request *rq = tio->orig;
> -
> rq->cmd_flags |= REQ_FAILED;
> - dm_complete_request(clone, error);
> + dm_complete_request(rq, error);
> }
> EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
At this point it might be worth to just kill the
dm_kill_unmapped_request wrapper?
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