8 files changed, 123 insertions, 65 deletions

diff --git a/block/blk-flush.c b/block/blk-flush.c
index ff87c664b7df..8ffee4b5f93d 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -225,7 +225,7 @@ static void flush_end_io(struct request *flush_rq, int error)
 
         if (q->mq_ops) {
                 spin_lock_irqsave(&q->mq_flush_lock, flags);
-                q->flush_rq->cmd_flags = 0;
+                q->flush_rq->tag = -1;
         }
 
         running = &q->flush_queue[q->flush_running_idx];
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index d90c4aeb7dd3..1aab39f71d95 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -221,8 +221,10 @@ static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt,
         return bs;
 }
 
-static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx,
-                  unsigned int *last_tag, gfp_t gfp)
+static int bt_get(struct blk_mq_alloc_data *data,
+                struct blk_mq_bitmap_tags *bt,
+                struct blk_mq_hw_ctx *hctx,
+                unsigned int *last_tag)
 {
         struct bt_wait_state *bs;
         DEFINE_WAIT(wait);
@@ -232,7 +234,7 @@ static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx,
         if (tag != -1)
                 return tag;
 
-        if (!(gfp & __GFP_WAIT))
+        if (!(data->gfp & __GFP_WAIT))
                 return -1;
 
         bs = bt_wait_ptr(bt, hctx);
@@ -249,50 +251,62 @@ static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx,
                 if (was_empty)
                         atomic_set(&bs->wait_cnt, bt->wake_cnt);
 
+                blk_mq_put_ctx(data->ctx);
+
                 io_schedule();
+
+                data->ctx = blk_mq_get_ctx(data->q);
+                data->hctx = data->q->mq_ops->map_queue(data->q,
+                                data->ctx->cpu);
+                if (data->reserved) {
+                        bt = &data->hctx->tags->breserved_tags;
+                } else {
+                        last_tag = &data->ctx->last_tag;
+                        hctx = data->hctx;
+                        bt = &hctx->tags->bitmap_tags;
+                }
+                finish_wait(&bs->wait, &wait);
+                bs = bt_wait_ptr(bt, hctx);
         } while (1);
 
         finish_wait(&bs->wait, &wait);
         return tag;
 }
 
-static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags,
-                                     struct blk_mq_hw_ctx *hctx,
-                                     unsigned int *last_tag, gfp_t gfp)
+static unsigned int __blk_mq_get_tag(struct blk_mq_alloc_data *data)
 {
         int tag;
 
-        tag = bt_get(&tags->bitmap_tags, hctx, last_tag, gfp);
+        tag = bt_get(data, &data->hctx->tags->bitmap_tags, data->hctx,
+                        &data->ctx->last_tag);
         if (tag >= 0)
-                return tag + tags->nr_reserved_tags;
+                return tag + data->hctx->tags->nr_reserved_tags;
 
         return BLK_MQ_TAG_FAIL;
 }
 
-static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags,
-                                              gfp_t gfp)
+static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_alloc_data *data)
 {
         int tag, zero = 0;
 
-        if (unlikely(!tags->nr_reserved_tags)) {
+        if (unlikely(!data->hctx->tags->nr_reserved_tags)) {
                 WARN_ON_ONCE(1);
                 return BLK_MQ_TAG_FAIL;
         }
 
-        tag = bt_get(&tags->breserved_tags, NULL, &zero, gfp);
+        tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL, &zero);
         if (tag < 0)
                 return BLK_MQ_TAG_FAIL;
 
         return tag;
 }
 
-unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag,
-                            gfp_t gfp, bool reserved)
+unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
 {
-        if (!reserved)
-                return __blk_mq_get_tag(hctx->tags, hctx, last_tag, gfp);
+        if (!data->reserved)
+                return __blk_mq_get_tag(data);
 
-        return __blk_mq_get_reserved_tag(hctx->tags, gfp);
+        return __blk_mq_get_reserved_tag(data);
 }
 
 static struct bt_wait_state *bt_wake_ptr(struct blk_mq_bitmap_tags *bt)
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index c959de58d2a5..98696a65d4d4 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -48,7 +48,7 @@ struct blk_mq_tags {
 extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node);
 extern void blk_mq_free_tags(struct blk_mq_tags *tags);
 
-extern unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, gfp_t gfp, bool reserved);
+extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);
 extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, unsigned int *last_tag);
 extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
 extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0f5879c42dcd..4e4cd6208052 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -33,28 +33,6 @@ static LIST_HEAD(all_q_list);
 
 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx);
 
-static struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
-                                           unsigned int cpu)
-{
-        return per_cpu_ptr(q->queue_ctx, cpu);
-}
-
-/*
- * This assumes per-cpu software queueing queues. They could be per-node
- * as well, for instance. For now this is hardcoded as-is. Note that we don't
- * care about preemption, since we know the ctx's are persistent. This does
- * mean that we can't rely on ctx always matching the currently running CPU.
- */
-static struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
-{
-        return __blk_mq_get_ctx(q, get_cpu());
-}
-
-static void blk_mq_put_ctx(struct blk_mq_ctx *ctx)
-{
-        put_cpu();
-}
-
 /*
  * Check if any of the ctx's have pending work in this hardware queue
  */
@@ -232,24 +210,23 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
 }
 
 static struct request *
-__blk_mq_alloc_request(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
-                struct blk_mq_ctx *ctx, int rw, gfp_t gfp, bool reserved)
+__blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw)
 {
         struct request *rq;
         unsigned int tag;
 
-        tag = blk_mq_get_tag(hctx, &ctx->last_tag, gfp, reserved);
+        tag = blk_mq_get_tag(data);