block: make the block holder code optional
Move the block holder code into a separate file as it is not in any way
related to the other block_dev.c code, and add a new selectable config
option for it so that we don't have to build it without any remapped
drivers selected.
The Kconfig symbol contains a _DEPRECATED suffix to match the comments
added in commit 49731baa41df
("block: restore multiple bd_link_disk_holder() support").
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20210804094147.459763-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/Kconfig b/block/Kconfig
index 15dfb76..bac87d7 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -241,4 +241,8 @@
config BLK_PM
def_bool BLOCK && PM
+# do not use in new code
+config BLOCK_HOLDER_DEPRECATED
+ bool
+
source "block/Kconfig.iosched"
