From: Omar Sandoval <[email protected]>

Wire up the sbitmap_get_shallow() operation to the tag code so that a
caller can limit the number of tags available to it.

Signed-off-by: Omar Sandoval <[email protected]>
---
 block/blk-mq-tag.c | 5 ++++-
 block/blk-mq.h     | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 9d97bfc4d465..d0be72ccb091 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -96,7 +96,10 @@ static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
        if (!(data->flags & BLK_MQ_REQ_INTERNAL) &&
            !hctx_may_queue(data->hctx, bt))
                return -1;
-       return __sbitmap_queue_get(bt);
+       if (data->shallow_depth)
+               return __sbitmap_queue_get_shallow(bt, data->shallow_depth);
+       else
+               return __sbitmap_queue_get(bt);
 }
 
 unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 8d49c06fc520..77ec66369f21 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -141,6 +141,7 @@ struct blk_mq_alloc_data {
        /* input parameter */
        struct request_queue *q;
        unsigned int flags;
+       unsigned int shallow_depth;
 
        /* input & output parameter */
        struct blk_mq_ctx *ctx;
-- 
2.12.2

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