block: move poll code to blk-mq

[mirror_ubuntu-artful-kernel.git] / block / blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 77110aed24ea075710949c8ef3a4598732a46375..ae8df5ec20d3860663bad8bdd2ef271f8eadc491 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2461,6 +2461,60 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
 }
 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
 
+static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
+{
+       struct request_queue *q = hctx->queue;
+       long state;
+
+       hctx->poll_considered++;
+
+       state = current->state;
+       while (!need_resched()) {
+               int ret;
+
+               hctx->poll_invoked++;
+
+               ret = q->mq_ops->poll(hctx, rq->tag);
+               if (ret > 0) {
+                       hctx->poll_success++;
+                       set_current_state(TASK_RUNNING);
+                       return true;
+               }
+
+               if (signal_pending_state(state, current))
+                       set_current_state(TASK_RUNNING);
+
+               if (current->state == TASK_RUNNING)
+                       return true;
+               if (ret < 0)
+                       break;
+               cpu_relax();
+       }
+
+       return false;
+}
+
+bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
+{
+       struct blk_mq_hw_ctx *hctx;
+       struct blk_plug *plug;
+       struct request *rq;
+
+       if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) ||
+           !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+               return false;
+
+       plug = current->plug;
+       if (plug)
+               blk_flush_plug_list(plug, false);
+
+       hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
+       rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie));
+
+       return __blk_mq_poll(hctx, rq);
+}
+EXPORT_SYMBOL_GPL(blk_mq_poll);
+
 void blk_mq_disable_hotplug(void)
 {
        mutex_lock(&all_q_mutex);