For a server/target appliance mode where we don't
necessarily care about specific IOs but rather want
to poll opportunisticly, it is useful to have a
non-selective polling interface.

Expose a blk_poll_batch for a batched blkdev polling
interface so our nvme target (and others) can use.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 block/blk-mq.c         | 14 ++++++++++++++
 include/linux/blk-mq.h |  2 ++
 include/linux/blkdev.h |  1 +
 3 files changed, 17 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index b2fd175e84d7..1962785b571a 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c

@@ -2911,6 +2911,20 @@ bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
 }
 EXPORT_SYMBOL_GPL(blk_mq_poll);
 
+int blk_mq_poll_batch(struct request_queue *q, unsigned int batch)
+{
+	struct blk_mq_hw_ctx *hctx;
+
+	if (!q->mq_ops || !q->mq_ops->poll_batch)
+		return 0;
+
+	hctx = blk_mq_map_queue(q, smp_processor_id());
+	return q->mq_ops->poll_batch(hctx, batch);
+}
+EXPORT_SYMBOL_GPL(blk_mq_poll_batch);
+
+
+