blk-mq: update ->init_request and ->exit_request prototypes

Remove the request_idx parameter, which can't be used safely now that we
support I/O schedulers with blk-mq.  Except for a superflous check in
mtip32xx it was unused anyway.

Also pass the tag_set instead of just the driver data - this allows drivers
to avoid some code duplication in a follow on cleanup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index bff7e3b..522d4fa 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -719,11 +719,10 @@ int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t)
 	return 0;
 }
 
-static int dm_mq_init_request(void *data, struct request *rq,
-		       unsigned int hctx_idx, unsigned int request_idx,
-		       unsigned int numa_node)
+static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
+		unsigned int hctx_idx, unsigned int numa_node)
 {
-	return __dm_rq_init_rq(data, rq);
+	return __dm_rq_init_rq(set->driver_data, rq);
 }
 
 static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,