Commit 248c7933 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-mq: make the blk-mq stacking code optional 



The code to stack blk-mq drivers is only used by dm-multipath, and
will preferably stay that way.  Make it optional and only selected
by device mapper, so that the buildbots more easily catch abuses
like the one that slipped in in the ufs driver in the last merged
window.  Another positive side effects is that kernel builds without
device mapper shrink a little bit as well.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220215100540.3892965-2-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f122d103

block/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -230,6 +230,9 @@ config BLK_PM 
config BLOCK_HOLDER_DEPRECATED

	bool



config BLK_MQ_STACKING

	bool



source "block/Kconfig.iosched"



endif # BLOCK

block/blk-mq.c

+2 −0
Original line number Diff line number Diff line
@@ -2840,6 +2840,7 @@ void blk_mq_submit_bio(struct bio *bio) 
				blk_mq_try_issue_directly(rq->mq_hctx, rq));

}



#ifdef CONFIG_BLK_MQ_STACKING

/**

 * blk_cloned_rq_check_limits - Helper function to check a cloned request

 *                              for the new queue limits
@@ -3017,6 +3018,7 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 
	return -ENOMEM;

}

EXPORT_SYMBOL_GPL(blk_rq_prep_clone);

#endif /* CONFIG_BLK_MQ_STACKING */



/*

 * Steal bios from a request and add them to a bio list.

drivers/md/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -204,6 +204,7 @@ config BLK_DEV_DM 
	tristate "Device mapper support"

	select BLOCK_HOLDER_DEPRECATED if SYSFS

	select BLK_DEV_DM_BUILTIN

	select BLK_MQ_STACKING

	depends on DAX || DAX=n

	help

	  Device-mapper is a low level volume manager.  It works by allowing