blk-mq: remove ->map_queue

All drivers use the default, so provide an inline version of it.  If we
ever need other queue mapping we can add an optional method back,
although supporting will also require major changes to the queue setup
code.

This provides better code generation, and better debugability as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/block/loop.c

@@ -1703,7 +1703,6 @@ static int loop_init_request(void *data, struct request *rq,
 
 static struct blk_mq_ops loop_mq_ops = {
 	.queue_rq       = loop_queue_rq,
-	.map_queue      = blk_mq_map_queue,
 	.init_request	= loop_init_request,
 };
 

drivers/block/mtip32xx/mtip32xx.c

@@ -3895,7 +3895,6 @@ exit_handler:
 
 static struct blk_mq_ops mtip_mq_ops = {
 	.queue_rq	= mtip_queue_rq,
-	.map_queue	= blk_mq_map_queue,
 	.init_request	= mtip_init_cmd,
 	.exit_request	= mtip_free_cmd,
 	.complete	= mtip_softirq_done_fn,

drivers/block/null_blk.c

@@ -393,7 +393,6 @@ static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
 
 static struct blk_mq_ops null_mq_ops = {
 	.queue_rq       = null_queue_rq,
-	.map_queue      = blk_mq_map_queue,
 	.init_hctx	= null_init_hctx,
 	.complete	= null_softirq_done_fn,
 };

drivers/block/rbd.c

@@ -3621,7 +3621,6 @@ static int rbd_init_request(void *data, struct request *rq,
 
 static struct blk_mq_ops rbd_mq_ops = {
 	.queue_rq	= rbd_queue_rq,
-	.map_queue	= blk_mq_map_queue,
 	.init_request	= rbd_init_request,
 };
 

drivers/block/virtio_blk.c

@@ -542,7 +542,6 @@ static int virtblk_init_request(void *data, struct request *rq,
 
 static struct blk_mq_ops virtio_mq_ops = {
 	.queue_rq	= virtio_queue_rq,
-	.map_queue	= blk_mq_map_queue,
 	.complete	= virtblk_request_done,
 	.init_request	= virtblk_init_request,
 };

drivers/block/xen-blkfront.c

@@ -909,7 +909,6 @@ out_busy:
 
 static struct blk_mq_ops blkfront_mq_ops = {
 	.queue_rq = blkif_queue_rq,
-	.map_queue = blk_mq_map_queue,
 };
 
 static void blkif_set_queue_limits(struct blkfront_info *info)