blk-mq: Export tagset iter function

Its useful to iterate on all the active tags in cases
where we will need to fail all the queues IO.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
[hch: carefully check for valid tagsets]
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index abdbb47..2fd0428 100644 (file)
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -474,6 +474,18 @@ void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn,
 }
 EXPORT_SYMBOL(blk_mq_all_tag_busy_iter);
 
+void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
+               busy_tag_iter_fn *fn, void *priv)
+{
+       int i;
+
+       for (i = 0; i < tagset->nr_hw_queues; i++) {
+               if (tagset->tags && tagset->tags[i])
+                       blk_mq_all_tag_busy_iter(tagset->tags[i], fn, priv);
+       }
+}
+EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
+
 void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
                void *priv)
 {

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 9ac9799..c808fec 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -240,6 +240,8 @@ void blk_mq_run_hw_queues(struct request_queue *q, bool async);
 void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
 void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn,
                void *priv);
+void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
+               busy_tag_iter_fn *fn, void *priv);
 void blk_mq_freeze_queue(struct request_queue *q);
 void blk_mq_unfreeze_queue(struct request_queue *q);
 void blk_mq_freeze_queue_start(struct request_queue *q);