From 205fb5f5ba1d8edcf18009998ed05b80b7d186af Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 30 Oct 2014 14:45:11 +0100 Subject: blk-mq: add blk_mq_unique_tag() The queuecommand() callback functions in SCSI low-level drivers need to know which hardware context has been selected by the block layer. Since this information is not available in the request structure, and since passing the hctx pointer directly to the queuecommand callback function would require modification of all SCSI LLDs, add a function to the block layer that allows to query the hardware context index. Signed-off-by: Bart Van Assche Acked-by: Jens Axboe Reviewed-by: Sagi Grimberg Reviewed-by: Martin K. Petersen Signed-off-by: Christoph Hellwig --- include/linux/blk-mq.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include') diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index c9be1589415a..15f7034aa377 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -167,6 +167,23 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, bool reserved); struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag); +enum { + BLK_MQ_UNIQUE_TAG_BITS = 16, + BLK_MQ_UNIQUE_TAG_MASK = (1 << BLK_MQ_UNIQUE_TAG_BITS) - 1, +}; + +u32 blk_mq_unique_tag(struct request *rq); + +static inline u16 blk_mq_unique_tag_to_hwq(u32 unique_tag) +{ + return unique_tag >> BLK_MQ_UNIQUE_TAG_BITS; +} + +static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag) +{ + return unique_tag & BLK_MQ_UNIQUE_TAG_MASK; +} + struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *, const int ctx_index); struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_tag_set *, unsigned int, int); -- cgit v1.3-18-gd494