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| author | Bart Van Assche <bvanassche@acm.org> | 2014-10-30 14:45:11 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-11-12 11:16:09 +0100 |
| commit | 205fb5f5ba1d8edcf18009998ed05b80b7d186af (patch) | |
| tree | 4f703687be0330fae7e7789f0a4534973535fd0a /block/blk-mq.c | |
| parent | f1569ff1d5ae0ca8598956be632947a88f540e2a (diff) | |
| download | lwn-205fb5f5ba1d8edcf18009998ed05b80b7d186af.tar.gz lwn-205fb5f5ba1d8edcf18009998ed05b80b7d186af.zip | |
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 <bvanassche@acm.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'block/blk-mq.c')
| -rw-r--r-- | block/blk-mq.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 68929bad9a6a..b5896d436fc9 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) |