struct request *last = NULL;
blk_mq_bio_to_request(rq, bio);
+
+ /*
+ * @request_count may become stale because of schedule
+ * out, so check the list again.
+ */
+ if (list_empty(&plug->mq_list))
+ request_count = 0;
if (!request_count)
trace_block_plug(q);
else
}
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);