Merge branch 'for-4.8/drivers' of git://git.kernel.dk/linux-block

[karo-tx-linux.git] / block / blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 2a1920c6d6e5ea4e6305cfb924ddf3a955f216ab..576e7112f8071179b0c8f44bef799dfa5bc75c33 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -263,10 +263,53 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
                blk_queue_exit(q);
                return ERR_PTR(-EWOULDBLOCK);
        }
+
+       rq->__data_len = 0;
+       rq->__sector = (sector_t) -1;
+       rq->bio = rq->biotail = NULL;
        return rq;
 }
 EXPORT_SYMBOL(blk_mq_alloc_request);
 
+struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw,
+               unsigned int flags, unsigned int hctx_idx)
+{
+       struct blk_mq_hw_ctx *hctx;
+       struct blk_mq_ctx *ctx;
+       struct request *rq;
+       struct blk_mq_alloc_data alloc_data;
+       int ret;
+
+       /*
+        * If the tag allocator sleeps we could get an allocation for a
+        * different hardware context.  No need to complicate the low level
+        * allocator for this for the rare use case of a command tied to
+        * a specific queue.
+        */
+       if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)))
+               return ERR_PTR(-EINVAL);
+
+       if (hctx_idx >= q->nr_hw_queues)
+               return ERR_PTR(-EIO);
+
+       ret = blk_queue_enter(q, true);
+       if (ret)
+               return ERR_PTR(ret);
+
+       hctx = q->queue_hw_ctx[hctx_idx];
+       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);
+       }
+
+       return rq;
+}
+EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
+
 static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
                                  struct blk_mq_ctx *ctx, struct request *rq)
 {