diff options
author | Mike Snitzer <snitzer@redhat.com> | 2016-02-20 14:02:49 -0500 |
---|---|---|
committer | Mike Snitzer <snitzer@redhat.com> | 2016-02-22 22:33:46 -0500 |
commit | c5248f79f39e5254977a3916b2149c3ccffa2722 (patch) | |
tree | bd8a3e1663a3596d88461be3a731ac060f65e345 | |
parent | 818c5f3bef750eb5998b468f84391e4d656b97ed (diff) | |
download | op-kernel-dev-c5248f79f39e5254977a3916b2149c3ccffa2722.zip op-kernel-dev-c5248f79f39e5254977a3916b2149c3ccffa2722.tar.gz |
dm: remove support for stacking dm-mq on .request_fn device(s)
Remove all fiddley code that propped up this support for a blk-mq
request-queue ontop of all .request_fn devices.
Testing has proven this niche request-based dm-mq mode to be buggy, when
testing fault tolerance with DM multipath, and there is no point trying
to preserve it.
Should help improve efficiency of pure dm-mq code and make code
maintenance less delicate.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-rw-r--r-- | drivers/md/dm-mpath.c | 5 | ||||
-rw-r--r-- | drivers/md/dm.c | 55 |
2 files changed, 20 insertions, 40 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 3ddaa11..7259eeba 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -418,7 +418,10 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, spin_unlock_irq(&m->lock); if (clone) { - /* Old request-based interface: allocated clone is passed in */ + /* + * Old request-based interface: allocated clone is passed in. + * Used by: .request_fn stacked on .request_fn path(s). + */ clone->q = bdev_get_queue(bdev); clone->rq_disk = bdev->bd_disk; clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 8a62e43..26fedd9 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1141,11 +1141,6 @@ static void free_rq_clone(struct request *clone) else if (!md->queue->mq_ops) /* request_fn queue stacked on request_fn queue(s) */ free_clone_request(md, clone); - /* - * NOTE: for the blk-mq queue stacked on request_fn queue(s) case: - * no need to call free_clone_request() because we leverage blk-mq by - * allocating the clone at the end of the blk-mq pdu (see: clone_rq) - */ if (!md->queue->mq_ops) free_rq_tio(tio); @@ -1866,24 +1861,18 @@ static struct request *clone_rq(struct request *rq, struct mapped_device *md, struct dm_rq_target_io *tio, gfp_t gfp_mask) { /* - * Do not allocate a clone if tio->clone was already set - * (see: dm_mq_queue_rq). + * Create clone for use with .request_fn request_queue */ - bool alloc_clone = !tio->clone; struct request *clone; - if (alloc_clone) { - clone = alloc_clone_request(md, gfp_mask); - if (!clone) - return NULL; - } else - clone = tio->clone; + clone = alloc_clone_request(md, gfp_mask); + if (!clone) + return NULL; blk_rq_init(NULL, clone); if (setup_clone(clone, rq, tio, gfp_mask)) { /* -ENOMEM */ - if (alloc_clone) - free_clone_request(md, clone); + free_clone_request(md, clone); return NULL; } @@ -2692,22 +2681,12 @@ static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, */ tio->ti = ti; - /* - * Both the table and md type cannot change after initial table load - */ - if (dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) { - /* clone request is allocated at the end of the pdu */ - tio->clone = (void *)blk_mq_rq_to_pdu(rq) + sizeof(struct dm_rq_target_io); - (void) clone_rq(rq, md, tio, GFP_ATOMIC); - queue_kthread_work(&md->kworker, &tio->work); - } else { - /* Direct call is fine since .queue_rq allows allocations */ - if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) { - /* Undo dm_start_request() before requeuing */ - rq_end_stats(md, rq); - rq_completed(md, rq_data_dir(rq), false); - return BLK_MQ_RQ_QUEUE_BUSY; - } + /* Direct call is fine since .queue_rq allows allocations */ + if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) { + /* Undo dm_start_request() before requeuing */ + rq_end_stats(md, rq); + rq_completed(md, rq_data_dir(rq), false); + return BLK_MQ_RQ_QUEUE_BUSY; } return BLK_MQ_RQ_QUEUE_OK; @@ -2726,6 +2705,11 @@ static int dm_init_request_based_blk_mq_queue(struct mapped_device *md) struct request_queue *q; int err; + if (dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) { + DMERR("request-based dm-mq may only be stacked on blk-mq device(s)"); + return -EINVAL; + } + md->tag_set = kzalloc(sizeof(struct blk_mq_tag_set), GFP_KERNEL); if (!md->tag_set) return -ENOMEM; @@ -2738,10 +2722,6 @@ static int dm_init_request_based_blk_mq_queue(struct mapped_device *md) md->tag_set->driver_data = md; md->tag_set->cmd_size = sizeof(struct dm_rq_target_io); - if (md_type == DM_TYPE_REQUEST_BASED) { - /* put the memory for non-blk-mq clone at the end of the pdu */ - md->tag_set->cmd_size += sizeof(struct request); - } err = blk_mq_alloc_tag_set(md->tag_set); if (err) @@ -2758,9 +2738,6 @@ static int dm_init_request_based_blk_mq_queue(struct mapped_device *md) /* backfill 'mq' sysfs registration normally done in blk_register_queue */ blk_mq_register_disk(md->disk); - if (md_type == DM_TYPE_REQUEST_BASED) - init_rq_based_worker_thread(md); - return 0; out_tag_set: |