Merge tag 'nfs-for-3.17-5' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
[deliverable/linux.git] / block / blk-mq.c
index 5189cb1e478a6b283609006364c01f9f8e31d082..383ea0cb1f0a295463789d956aae820b334f4a55 100644 (file)
@@ -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);
@@ -1309,6 +1321,7 @@ static void blk_mq_free_rq_map(struct blk_mq_tag_set *set,
                                continue;
                        set->ops->exit_request(set->driver_data, tags->rqs[i],
                                                hctx_idx, i);
+                       tags->rqs[i] = NULL;
                }
        }
 
@@ -1342,8 +1355,9 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
 
        INIT_LIST_HEAD(&tags->page_list);
 
-       tags->rqs = kmalloc_node(set->queue_depth * sizeof(struct request *),
-                                       GFP_KERNEL, set->numa_node);
+       tags->rqs = kzalloc_node(set->queue_depth * sizeof(struct request *),
+                                GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY,
+                                set->numa_node);
        if (!tags->rqs) {
                blk_mq_free_tags(tags);
                return NULL;
@@ -1367,8 +1381,9 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
                        this_order--;
 
                do {
-                       page = alloc_pages_node(set->numa_node, GFP_KERNEL,
-                                               this_order);
+                       page = alloc_pages_node(set->numa_node,
+                               GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY,
+                               this_order);
                        if (page)
                                break;
                        if (!this_order--)
@@ -1392,8 +1407,10 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
                        if (set->ops->init_request) {
                                if (set->ops->init_request(set->driver_data,
                                                tags->rqs[i], hctx_idx, i,
-                                               set->numa_node))
+                                               set->numa_node)) {
+                                       tags->rqs[i] = NULL;
                                        goto fail;
+                               }
                        }
 
                        p += rq_size;
@@ -1404,7 +1421,6 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
        return tags;
 
 fail:
-       pr_warn("%s: failed to allocate requests\n", __func__);
        blk_mq_free_rq_map(set, tags, hctx_idx);
        return NULL;
 }
@@ -1574,7 +1590,7 @@ 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 +1678,8 @@ 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 +1729,10 @@ 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,
@@ -1928,6 +1940,61 @@ static int blk_mq_queue_reinit_notify(struct notifier_block *nb,
        return NOTIFY_OK;
 }
 
+static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
+{
+       int i;
+
+       for (i = 0; i < set->nr_hw_queues; i++) {
+               set->tags[i] = blk_mq_init_rq_map(set, i);
+               if (!set->tags[i])
+                       goto out_unwind;
+       }
+
+       return 0;
+
+out_unwind:
+       while (--i >= 0)
+               blk_mq_free_rq_map(set, set->tags[i], i);
+
+       set->tags = NULL;
+       return -ENOMEM;
+}
+
+/*
+ * Allocate the request maps associated with this tag_set. Note that this
+ * may reduce the depth asked for, if memory is tight. set->queue_depth
+ * will be updated to reflect the allocated depth.
+ */
+static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
+{
+       unsigned int depth;
+       int err;
+
+       depth = set->queue_depth;
+       do {
+               err = __blk_mq_alloc_rq_maps(set);
+               if (!err)
+                       break;
+
+               set->queue_depth >>= 1;
+               if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
+                       err = -ENOMEM;
+                       break;
+               }
+       } while (set->queue_depth);
+
+       if (!set->queue_depth || err) {
+               pr_err("blk-mq: failed to allocate request map\n");
+               return -ENOMEM;
+       }
+
+       if (depth != set->queue_depth)
+               pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
+                                               depth, set->queue_depth);
+
+       return 0;
+}
+
 /*
  * Alloc a tag set to be associated with one or more request queues.
  * May fail with EINVAL for various error conditions. May adjust the
@@ -1936,8 +2003,6 @@ static int blk_mq_queue_reinit_notify(struct notifier_block *nb,
  */
 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
 {
-       int i;
-
        if (!set->nr_hw_queues)
                return -EINVAL;
        if (!set->queue_depth)
@@ -1958,23 +2023,18 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
                                 sizeof(struct blk_mq_tags *),
                                 GFP_KERNEL, set->numa_node);
        if (!set->tags)
-               goto out;
+               return -ENOMEM;
 
-       for (i = 0; i < set->nr_hw_queues; i++) {
-               set->tags[i] = blk_mq_init_rq_map(set, i);
-               if (!set->tags[i])
-                       goto out_unwind;
-       }
+       if (blk_mq_alloc_rq_maps(set))
+               goto enomem;
 
        mutex_init(&set->tag_list_lock);
        INIT_LIST_HEAD(&set->tag_list);
 
        return 0;
-
-out_unwind:
-       while (--i >= 0)
-               blk_mq_free_rq_map(set, set->tags[i], i);
-out:
+enomem:
+       kfree(set->tags);
+       set->tags = NULL;
        return -ENOMEM;
 }
 EXPORT_SYMBOL(blk_mq_alloc_tag_set);
@@ -1989,6 +2049,7 @@ void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
        }
 
        kfree(set->tags);
+       set->tags = NULL;
 }
 EXPORT_SYMBOL(blk_mq_free_tag_set);
 
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