diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq-tag.c | 28 | ||||
| -rw-r--r-- | block/blk-mq.c | 2 |
2 files changed, 30 insertions, 0 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 8317175a300..728b9a4d5f5 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -584,6 +584,34 @@ int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int tdepth) return 0; } +/** + * blk_mq_unique_tag() - return a tag that is unique queue-wide + * @rq: request for which to compute a unique tag + * + * The tag field in struct request is unique per hardware queue but not over + * all hardware queues. Hence this function that returns a tag with the + * hardware context index in the upper bits and the per hardware queue tag in + * the lower bits. + * + * Note: When called for a request that is queued on a non-multiqueue request + * queue, the hardware context index is set to zero. + */ +u32 blk_mq_unique_tag(struct request *rq) +{ + struct request_queue *q = rq->q; + struct blk_mq_hw_ctx *hctx; + int hwq = 0; + + if (q->mq_ops) { + hctx = q->mq_ops->map_queue(q, rq->mq_ctx->cpu); + hwq = hctx->queue_num; + } + + return (hwq << BLK_MQ_UNIQUE_TAG_BITS) | + (rq->tag & BLK_MQ_UNIQUE_TAG_MASK); +} +EXPORT_SYMBOL(blk_mq_unique_tag); + ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page) { char *orig_page = page; diff --git a/block/blk-mq.c b/block/blk-mq.c index 68929bad9a6..b5896d436fc 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2024,6 +2024,8 @@ static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) */ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) { + BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); + if (!set->nr_hw_queues) return -EINVAL; if (!set->queue_depth) |