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authorJens Axboe <axboe@kernel.dk>2018-10-10 20:49:26 -0600
committerMike Snitzer <snitzer@redhat.com>2018-10-11 11:36:09 -0400
commit6a23e05c2fe3c64ec012fd81e51e3ab51e4f2f9f (patch)
tree43687a888b009ec49092138e6d691503669b4dc1 /drivers/md/dm-rq.c
parent118aa47c7072bce05fc39bd40a1c0a90caed72ab (diff)
downloadlinux-6a23e05c2fe3c64ec012fd81e51e3ab51e4f2f9f.tar.bz2
dm: remove legacy request-based IO path
dm supports both, and since we're killing off the legacy path in general, get rid of it in dm. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-rq.c')
-rw-r--r--drivers/md/dm-rq.c316
1 files changed, 26 insertions, 290 deletions
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 6e547b8dd298..7cd36e4d1310 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -23,19 +23,6 @@ static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
#define RESERVED_REQUEST_BASED_IOS 256
static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
-static bool use_blk_mq = IS_ENABLED(CONFIG_DM_MQ_DEFAULT);
-
-bool dm_use_blk_mq_default(void)
-{
- return use_blk_mq;
-}
-
-bool dm_use_blk_mq(struct mapped_device *md)
-{
- return md->use_blk_mq;
-}
-EXPORT_SYMBOL_GPL(dm_use_blk_mq);
-
unsigned dm_get_reserved_rq_based_ios(void)
{
return __dm_get_module_param(&reserved_rq_based_ios,
@@ -59,41 +46,13 @@ int dm_request_based(struct mapped_device *md)
return queue_is_rq_based(md->queue);
}
-static void dm_old_start_queue(struct request_queue *q)
-{
- unsigned long flags;
-
- spin_lock_irqsave(q->queue_lock, flags);
- if (blk_queue_stopped(q))
- blk_start_queue(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-static void dm_mq_start_queue(struct request_queue *q)
+void dm_start_queue(struct request_queue *q)
{
blk_mq_unquiesce_queue(q);
blk_mq_kick_requeue_list(q);
}
-void dm_start_queue(struct request_queue *q)
-{
- if (!q->mq_ops)
- dm_old_start_queue(q);
- else
- dm_mq_start_queue(q);
-}
-
-static void dm_old_stop_queue(struct request_queue *q)
-{
- unsigned long flags;
-
- spin_lock_irqsave(q->queue_lock, flags);
- if (!blk_queue_stopped(q))
- blk_stop_queue(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-static void dm_mq_stop_queue(struct request_queue *q)
+void dm_stop_queue(struct request_queue *q)
{
if (blk_mq_queue_stopped(q))
return;
@@ -101,14 +60,6 @@ static void dm_mq_stop_queue(struct request_queue *q)
blk_mq_quiesce_queue(q);
}
-void dm_stop_queue(struct request_queue *q)
-{
- if (!q->mq_ops)
- dm_old_stop_queue(q);
- else
- dm_mq_stop_queue(q);
-}
-
/*
* Partial completion handling for request-based dm
*/
@@ -179,9 +130,6 @@ static void rq_end_stats(struct mapped_device *md, struct request *orig)
*/
static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
{
- struct request_queue *q = md->queue;
- unsigned long flags;
-
atomic_dec(&md->pending[rw]);
/* nudge anyone waiting on suspend queue */
@@ -189,18 +137,6 @@ static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
wake_up(&md->wait);
/*
- * Run this off this callpath, as drivers could invoke end_io while
- * inside their request_fn (and holding the queue lock). Calling
- * back into ->request_fn() could deadlock attempting to grab the
- * queue lock again.
- */
- if (!q->mq_ops && run_queue) {
- spin_lock_irqsave(q->queue_lock, flags);
- blk_run_queue_async(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
- }
-
- /*
* dm_put() must be at the end of this function. See the comment above
*/
dm_put(md);
@@ -222,27 +158,10 @@ static void dm_end_request(struct request *clone, blk_status_t error)
tio->ti->type->release_clone_rq(clone);
rq_end_stats(md, rq);
- if (!rq->q->mq_ops)
- blk_end_request_all(rq, error);
- else
- blk_mq_end_request(rq, error);
+ blk_mq_end_request(rq, error);
rq_completed(md, rw, true);
}
-/*
- * Requeue the original request of a clone.
- */
-static void dm_old_requeue_request(struct request *rq, unsigned long delay_ms)
-{
- struct request_queue *q = rq->q;
- unsigned long flags;
-
- spin_lock_irqsave(q->queue_lock, flags);
- blk_requeue_request(q, rq);
- blk_delay_queue(q, delay_ms);
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs)
{
blk_mq_delay_kick_requeue_list(q, msecs);
@@ -273,11 +192,7 @@ static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_
tio->ti->type->release_clone_rq(tio->clone);
}
- if (!rq->q->mq_ops)
- dm_old_requeue_request(rq, delay_ms);
- else
- dm_mq_delay_requeue_request(rq, delay_ms);
-
+ dm_mq_delay_requeue_request(rq, delay_ms);
rq_completed(md, rw, false);
}
@@ -340,10 +255,7 @@ static void dm_softirq_done(struct request *rq)
rq_end_stats(md, rq);
rw = rq_data_dir(rq);
- if (!rq->q->mq_ops)
- blk_end_request_all(rq, tio->error);
- else
- blk_mq_end_request(rq, tio->error);
+ blk_mq_end_request(rq, tio->error);
rq_completed(md, rw, false);
return;
}
@@ -363,17 +275,14 @@ static void dm_complete_request(struct request *rq, blk_status_t error)
struct dm_rq_target_io *tio = tio_from_request(rq);
tio->error = error;
- if (!rq->q->mq_ops)
- blk_complete_request(rq);
- else
- blk_mq_complete_request(rq);
+ blk_mq_complete_request(rq);
}
/*
* Complete the not-mapped clone and the original request with the error status
* through softirq context.
* Target's rq_end_io() function isn't called.
- * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
+ * This may be used when the target's clone_and_map_rq() function fails.
*/
static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
{
@@ -381,21 +290,10 @@ static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
dm_complete_request(rq, error);
}
-/*
- * Called with the clone's queue lock held (in the case of .request_fn)
- */
static void end_clone_request(struct request *clone, blk_status_t error)
{
struct dm_rq_target_io *tio = clone->end_io_data;
- /*
- * Actual request completion is done in a softirq context which doesn't
- * hold the clone's queue lock. Otherwise, deadlock could occur because:
- * - another request may be submitted by the upper level driver
- * of the stacking during the completion
- * - the submission which requires queue lock may be done
- * against this clone's queue
- */
dm_complete_request(tio->orig, error);
}
@@ -446,8 +344,6 @@ static int setup_clone(struct request *clone, struct request *rq,
return 0;
}
-static void map_tio_request(struct kthread_work *work);
-
static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
struct mapped_device *md)
{
@@ -464,8 +360,6 @@ static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
*/
if (!md->init_tio_pdu)
memset(&tio->info, 0, sizeof(tio->info));
- if (md->kworker_task)
- kthread_init_work(&tio->work, map_tio_request);
}
/*
@@ -504,10 +398,7 @@ check_again:
blk_rq_unprep_clone(clone);
tio->ti->type->release_clone_rq(clone);
tio->clone = NULL;
- if (!rq->q->mq_ops)
- r = DM_MAPIO_DELAY_REQUEUE;
- else
- r = DM_MAPIO_REQUEUE;
+ r = DM_MAPIO_REQUEUE;
goto check_again;
}
break;
@@ -530,20 +421,23 @@ check_again:
return r;
}
+/* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */
+ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
+{
+ return sprintf(buf, "%u\n", 0);
+}
+
+ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
+ const char *buf, size_t count)
+{
+ return count;
+}
+
static void dm_start_request(struct mapped_device *md, struct request *orig)
{
- if (!orig->q->mq_ops)
- blk_start_request(orig);
- else
- blk_mq_start_request(orig);
+ blk_mq_start_request(orig);
atomic_inc(&md->pending[rq_data_dir(orig)]);
- if (md->seq_rq_merge_deadline_usecs) {
- md->last_rq_pos = rq_end_sector(orig);
- md->last_rq_rw = rq_data_dir(orig);
- md->last_rq_start_time = ktime_get();
- }
-
if (unlikely(dm_stats_used(&md->stats))) {
struct dm_rq_target_io *tio = tio_from_request(orig);
tio->duration_jiffies = jiffies;
@@ -563,8 +457,10 @@ static void dm_start_request(struct mapped_device *md, struct request *orig)
dm_get(md);
}
-static int __dm_rq_init_rq(struct mapped_device *md, struct request *rq)
+static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
+ unsigned int hctx_idx, unsigned int numa_node)
{
+ struct mapped_device *md = set->driver_data;
struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
/*
@@ -581,163 +477,6 @@ static int __dm_rq_init_rq(struct mapped_device *md, struct request *rq)
return 0;
}
-static int dm_rq_init_rq(struct request_queue *q, struct request *rq, gfp_t gfp)
-{
- return __dm_rq_init_rq(q->rq_alloc_data, rq);
-}
-
-static void map_tio_request(struct kthread_work *work)
-{
- struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
-
- if (map_request(tio) == DM_MAPIO_REQUEUE)
- dm_requeue_original_request(tio, false);
-}
-
-ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
-{
- return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs);
-}
-
-#define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
-
-ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
- const char *buf, size_t count)
-{
- unsigned deadline;
-
- if (dm_get_md_type(md) != DM_TYPE_REQUEST_BASED)
- return count;
-
- if (kstrtouint(buf, 10, &deadline))
- return -EINVAL;
-
- if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS)
- deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS;
-
- md->seq_rq_merge_deadline_usecs = deadline;
-
- return count;
-}
-
-static bool dm_old_request_peeked_before_merge_deadline(struct mapped_device *md)
-{
- ktime_t kt_deadline;
-
- if (!md->seq_rq_merge_deadline_usecs)
- return false;
-
- kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC);
- kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline);
-
- return !ktime_after(ktime_get(), kt_deadline);
-}
-
-/*
- * q->request_fn for old request-based dm.
- * Called with the queue lock held.
- */
-static void dm_old_request_fn(struct request_queue *q)
-{
- struct mapped_device *md = q->queuedata;
- struct dm_target *ti = md->immutable_target;
- struct request *rq;
- struct dm_rq_target_io *tio;
- sector_t pos = 0;
-
- if (unlikely(!ti)) {
- int srcu_idx;
- struct dm_table *map = dm_get_live_table(md, &srcu_idx);
-
- if (unlikely(!map)) {
- dm_put_live_table(md, srcu_idx);
- return;
- }
- ti = dm_table_find_target(map, pos);
- dm_put_live_table(md, srcu_idx);
- }
-
- /*
- * For suspend, check blk_queue_stopped() and increment
- * ->pending within a single queue_lock not to increment the
- * number of in-flight I/Os after the queue is stopped in
- * dm_suspend().
- */
- while (!blk_queue_stopped(q)) {
- rq = blk_peek_request(q);
- if (!rq)
- return;
-
- /* always use block 0 to find the target for flushes for now */
- pos = 0;
- if (req_op(rq) != REQ_OP_FLUSH)
- pos = blk_rq_pos(rq);
-
- if ((dm_old_request_peeked_before_merge_deadline(md) &&
- md_in_flight(md) && rq->bio && !bio_multiple_segments(rq->bio) &&
- md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) ||
- (ti->type->busy && ti->type->busy(ti))) {
- blk_delay_queue(q, 10);
- return;
- }
-
- dm_start_request(md, rq);
-
- tio = tio_from_request(rq);
- init_tio(tio, rq, md);
- /* Establish tio->ti before queuing work (map_tio_request) */
- tio->ti = ti;
- kthread_queue_work(&md->kworker, &tio->work);
- BUG_ON(!irqs_disabled());
- }
-}
-
-/*
- * Fully initialize a .request_fn request-based queue.
- */
-int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t)
-{
- struct dm_target *immutable_tgt;
-
- /* Fully initialize the queue */
- md->queue->cmd_size = sizeof(struct dm_rq_target_io);
- md->queue->rq_alloc_data = md;
- md->queue->request_fn = dm_old_request_fn;
- md->queue->init_rq_fn = dm_rq_init_rq;
-
- immutable_tgt = dm_table_get_immutable_target(t);
- if (immutable_tgt && immutable_tgt->per_io_data_size) {
- /* any target-specific per-io data is immediately after the tio */
- md->queue->cmd_size += immutable_tgt->per_io_data_size;
- md->init_tio_pdu = true;
- }
- if (blk_init_allocated_queue(md->queue) < 0)
- return -EINVAL;
-
- /* disable dm_old_request_fn's merge heuristic by default */
- md->seq_rq_merge_deadline_usecs = 0;
-
- blk_queue_softirq_done(md->queue, dm_softirq_done);
-
- /* Initialize the request-based DM worker thread */
- kthread_init_worker(&md->kworker);
- md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
- "kdmwork-%s", dm_device_name(md));
- if (IS_ERR(md->kworker_task)) {
- int error = PTR_ERR(md->kworker_task);
- md->kworker_task = NULL;
- return error;
- }
-
- return 0;
-}
-
-static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
- unsigned int hctx_idx, unsigned int numa_node)
-{
- return __dm_rq_init_rq(set->driver_data, rq);
-}
-
static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
@@ -790,11 +529,6 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
struct dm_target *immutable_tgt;
int err;
- if (!dm_table_all_blk_mq_devices(t)) {
- DMERR("request-based dm-mq may only be stacked on blk-mq device(s)");
- return -EINVAL;
- }
-
md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
if (!md->tag_set)
return -ENOMEM;
@@ -845,6 +579,8 @@ void dm_mq_cleanup_mapped_device(struct mapped_device *md)
module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
+/* Unused, but preserved for userspace compatibility */
+static bool use_blk_mq = true;
module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");