Merge tag 'mvebu-fixes-3.17' of git://git.infradead.org/linux-mvebu into next/fixes...

[cascardo/linux.git] / block / blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5189cb1..4aac826 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -112,18 +112,22 @@ static void blk_mq_usage_counter_release(struct percpu_ref *ref)
  */
 void blk_mq_freeze_queue(struct request_queue *q)
 {
+       bool freeze;
+
        spin_lock_irq(q->queue_lock);
-       q->mq_freeze_depth++;
+       freeze = !q->mq_freeze_depth++;
        spin_unlock_irq(q->queue_lock);
 
-       percpu_ref_kill(&q->mq_usage_counter);
-       blk_mq_run_queues(q, false);
+       if (freeze) {
+               percpu_ref_kill(&q->mq_usage_counter);
+               blk_mq_run_queues(q, false);
+       }
        wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->mq_usage_counter));
 }
 
 static void blk_mq_unfreeze_queue(struct request_queue *q)
 {
-       bool wake = false;
+       bool wake;
 
        spin_lock_irq(q->queue_lock);
        wake = !--q->mq_freeze_depth;
@@ -172,6 +176,8 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
        /* tag was already set */
        rq->errors = 0;
 
+       rq->cmd = rq->__cmd;
+
        rq->extra_len = 0;
        rq->sense_len = 0;
        rq->resid_len = 0;
@@ -1068,13 +1074,17 @@ static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
                blk_account_io_start(rq, 1);
 }
 
+static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx)
+{
+       return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
+               !blk_queue_nomerges(hctx->queue);
+}
+
 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx,
                                         struct blk_mq_ctx *ctx,
                                         struct request *rq, struct bio *bio)
 {
-       struct request_queue *q = hctx->queue;
-
-       if (!(hctx->flags & BLK_MQ_F_SHOULD_MERGE)) {
+       if (!hctx_allow_merges(hctx)) {
                blk_mq_bio_to_request(rq, bio);
                spin_lock(&ctx->lock);
 insert_rq:
@@ -1082,6 +1092,8 @@ insert_rq:
                spin_unlock(&ctx->lock);
                return false;
        } else {
+               struct request_queue *q = hctx->queue;
+
                spin_lock(&ctx->lock);
                if (!blk_mq_attempt_merge(q, ctx, bio)) {
                        blk_mq_bio_to_request(rq, bio);
@@ -1574,7 +1586,7 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
                hctx->tags = set->tags[i];
 
                /*
-                * Allocate space for all possible cpus to avoid allocation in
+                * Allocate space for all possible cpus to avoid allocation at
                 * runtime
                 */
                hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *),
@@ -1662,8 +1674,8 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 
        queue_for_each_hw_ctx(q, hctx, i) {
                /*
-                * If not software queues are mapped to this hardware queue,
-                * disable it and free the request entries
+                * If no software queues are mapped to this hardware queue,
+                * disable it and free the request entries.
                 */
                if (!hctx->nr_ctx) {
                        struct blk_mq_tag_set *set = q->tag_set;
@@ -1713,14 +1725,10 @@ static void blk_mq_del_queue_tag_set(struct request_queue *q)
 {
        struct blk_mq_tag_set *set = q->tag_set;
 
-       blk_mq_freeze_queue(q);
-
        mutex_lock(&set->tag_list_lock);
        list_del_init(&q->tag_set_list);
        blk_mq_update_tag_set_depth(set);
        mutex_unlock(&set->tag_list_lock);
-
-       blk_mq_unfreeze_queue(q);
 }
 
 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,