static int blk_mq_queue_enter(struct request_queue *q)
{
- int ret;
-
- __percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
- smp_wmb();
-
- /* we have problems freezing the queue if it's initializing */
- if (!blk_queue_dying(q) &&
- (!blk_queue_bypass(q) || !blk_queue_init_done(q)))
- return 0;
-
- __percpu_counter_add(&q->mq_usage_counter, -1, 1000000);
+ while (true) {
+ int ret;
- spin_lock_irq(q->queue_lock);
- ret = wait_event_interruptible_lock_irq(q->mq_freeze_wq,
- !blk_queue_bypass(q) || blk_queue_dying(q),
- *q->queue_lock);
- /* inc usage with lock hold to avoid freeze_queue runs here */
- if (!ret && !blk_queue_dying(q))
- __percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
- else if (blk_queue_dying(q))
- ret = -ENODEV;
- spin_unlock_irq(q->queue_lock);
+ if (percpu_ref_tryget_live(&q->mq_usage_counter))
+ return 0;
- return ret;
+ ret = wait_event_interruptible(q->mq_freeze_wq,
+ !q->mq_freeze_depth || blk_queue_dying(q));
+ if (blk_queue_dying(q))
+ return -ENODEV;
+ if (ret)
+ return ret;
+ }
}
static void blk_mq_queue_exit(struct request_queue *q)
{
- __percpu_counter_add(&q->mq_usage_counter, -1, 1000000);
+ percpu_ref_put(&q->mq_usage_counter);
}
-void blk_mq_drain_queue(struct request_queue *q)
+static void blk_mq_usage_counter_release(struct percpu_ref *ref)
{
- while (true) {
- s64 count;
-
- spin_lock_irq(q->queue_lock);
- count = percpu_counter_sum(&q->mq_usage_counter);
- spin_unlock_irq(q->queue_lock);
+ struct request_queue *q =
+ container_of(ref, struct request_queue, mq_usage_counter);
- if (count == 0)
- break;
- blk_mq_start_hw_queues(q);
- msleep(10);
- }
+ wake_up_all(&q->mq_freeze_wq);
}
/*
* Guarantee no request is in use, so we can change any data structure of
* the queue afterward.
*/
-static void blk_mq_freeze_queue(struct request_queue *q)
+void blk_mq_freeze_queue(struct request_queue *q)
{
- bool drain;
+ bool freeze;
spin_lock_irq(q->queue_lock);
- drain = !q->bypass_depth++;
- queue_flag_set(QUEUE_FLAG_BYPASS, q);
+ freeze = !q->mq_freeze_depth++;
spin_unlock_irq(q->queue_lock);
- if (drain)
- blk_mq_drain_queue(q);
+ 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);
- if (!--q->bypass_depth) {
- queue_flag_clear(QUEUE_FLAG_BYPASS, q);
- wake = true;
- }
- WARN_ON_ONCE(q->bypass_depth < 0);
+ wake = !--q->mq_freeze_depth;
+ WARN_ON_ONCE(q->mq_freeze_depth < 0);
spin_unlock_irq(q->queue_lock);
- if (wake)
+ if (wake) {
+ percpu_ref_reinit(&q->mq_usage_counter);
wake_up_all(&q->mq_freeze_wq);
+ }
}
bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
/* tag was already set */
rq->errors = 0;
+ rq->cmd = rq->__cmd;
+
rq->extra_len = 0;
rq->sense_len = 0;
rq->resid_len = 0;
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:
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);
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 *),
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;
{
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,
if (!q)
goto err_hctxs;
- if (percpu_counter_init(&q->mq_usage_counter, 0))
+ if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release))
goto err_map;
setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q);
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
blk_mq_free_hw_queues(q, set);
- percpu_counter_destroy(&q->mq_usage_counter);
+ percpu_ref_exit(&q->mq_usage_counter);
free_percpu(q->queue_ctx);
kfree(q->queue_hw_ctx);
{
blk_mq_cpu_init();
- /* Must be called after percpu_counter_hotcpu_callback() */
- hotcpu_notifier(blk_mq_queue_reinit_notify, -10);
+ hotcpu_notifier(blk_mq_queue_reinit_notify, 0);
return 0;
}
projects / cascardo / linux.git / blobdiff