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Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c76
1 files changed, 33 insertions, 43 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e931a0e8e73d..c207fa9870eb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -296,17 +296,29 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw,
if (ret)
return ERR_PTR(ret);
+ /*
+ * Check if the hardware context is actually mapped to anything.
+ * If not tell the caller that it should skip this queue.
+ */
hctx = q->queue_hw_ctx[hctx_idx];
+ if (!blk_mq_hw_queue_mapped(hctx)) {
+ ret = -EXDEV;
+ goto out_queue_exit;
+ }
ctx = __blk_mq_get_ctx(q, cpumask_first(hctx->cpumask));
blk_mq_set_alloc_data(&alloc_data, q, flags, ctx, hctx);
rq = __blk_mq_alloc_request(&alloc_data, rw, 0);
if (!rq) {
- blk_queue_exit(q);
- return ERR_PTR(-EWOULDBLOCK);
+ ret = -EWOULDBLOCK;
+ goto out_queue_exit;
}
return rq;
+
+out_queue_exit:
+ blk_queue_exit(q);
+ return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
@@ -793,11 +805,12 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
struct list_head *dptr;
int queued;
- WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask));
-
if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
return;
+ WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
+ cpu_online(hctx->next_cpu));
+
hctx->run++;
/*
@@ -1036,10 +1049,11 @@ void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
EXPORT_SYMBOL(blk_mq_delay_queue);
static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
- struct blk_mq_ctx *ctx,
struct request *rq,
bool at_head)
{
+ struct blk_mq_ctx *ctx = rq->mq_ctx;
+
trace_block_rq_insert(hctx->queue, rq);
if (at_head)
@@ -1053,20 +1067,16 @@ static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
{
struct blk_mq_ctx *ctx = rq->mq_ctx;
- __blk_mq_insert_req_list(hctx, ctx, rq, at_head);
+ __blk_mq_insert_req_list(hctx, rq, at_head);
blk_mq_hctx_mark_pending(hctx, ctx);
}
void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
- bool async)
+ bool async)
{
+ struct blk_mq_ctx *ctx = rq->mq_ctx;
struct request_queue *q = rq->q;
struct blk_mq_hw_ctx *hctx;
- struct blk_mq_ctx *ctx = rq->mq_ctx, *current_ctx;
-
- current_ctx = blk_mq_get_ctx(q);
- if (!cpu_online(ctx->cpu))
- rq->mq_ctx = ctx = current_ctx;
hctx = q->mq_ops->map_queue(q, ctx->cpu);
@@ -1076,8 +1086,6 @@ void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
if (run_queue)
blk_mq_run_hw_queue(hctx, async);
-
- blk_mq_put_ctx(current_ctx);
}
static void blk_mq_insert_requests(struct request_queue *q,
@@ -1088,14 +1096,9 @@ static void blk_mq_insert_requests(struct request_queue *q,
{
struct blk_mq_hw_ctx *hctx;
- struct blk_mq_ctx *current_ctx;
trace_block_unplug(q, depth, !from_schedule);
- current_ctx = blk_mq_get_ctx(q);
-
- if (!cpu_online(ctx->cpu))
- ctx = current_ctx;
hctx = q->mq_ops->map_queue(q, ctx->cpu);
/*
@@ -1107,15 +1110,14 @@ static void blk_mq_insert_requests(struct request_queue *q,
struct request *rq;
rq = list_first_entry(list, struct request, queuelist);
+ BUG_ON(rq->mq_ctx != ctx);
list_del_init(&rq->queuelist);
- rq->mq_ctx = ctx;
- __blk_mq_insert_req_list(hctx, ctx, rq, false);
+ __blk_mq_insert_req_list(hctx, rq, false);
}
blk_mq_hctx_mark_pending(hctx, ctx);
spin_unlock(&ctx->lock);
blk_mq_run_hw_queue(hctx, from_schedule);
- blk_mq_put_ctx(current_ctx);
}
static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b)
@@ -1630,16 +1632,17 @@ static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap *bitmap, int node)
return 0;
}
+/*
+ * 'cpu' is going away. splice any existing rq_list entries from this
+ * software queue to the hw queue dispatch list, and ensure that it
+ * gets run.
+ */
static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu)
{
- struct request_queue *q = hctx->queue;
struct blk_mq_ctx *ctx;
LIST_HEAD(tmp);
- /*
- * Move ctx entries to new CPU, if this one is going away.
- */
- ctx = __blk_mq_get_ctx(q, cpu);
+ ctx = __blk_mq_get_ctx(hctx->queue, cpu);
spin_lock(&ctx->lock);
if (!list_empty(&ctx->rq_list)) {
@@ -1651,24 +1654,11 @@ static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu)
if (list_empty(&tmp))
return NOTIFY_OK;
- ctx = blk_mq_get_ctx(q);
- spin_lock(&ctx->lock);
-
- while (!list_empty(&tmp)) {
- struct request *rq;
-
- rq = list_first_entry(&tmp, struct request, queuelist);
- rq->mq_ctx = ctx;
- list_move_tail(&rq->queuelist, &ctx->rq_list);
- }
-
- hctx = q->mq_ops->map_queue(q, ctx->cpu);
- blk_mq_hctx_mark_pending(hctx, ctx);
-
- spin_unlock(&ctx->lock);
+ spin_lock(&hctx->lock);
+ list_splice_tail_init(&tmp, &hctx->dispatch);
+ spin_unlock(&hctx->lock);
blk_mq_run_hw_queue(hctx, true);
- blk_mq_put_ctx(ctx);
return NOTIFY_OK;
}