[SRU][Xenial][PATCH 1/1] bcache: partition support: add 16 minors per bcacheN device

[Joseph Salisbury]

From: Eric Wheeler <git at linux.ewheeler.net>

BugLink: http://bugs.launchpad.net/bugs/1705493

Signed-off-by: Eric Wheeler <bcache at linux.ewheeler.net>
Tested-by: Wido den Hollander <wido at widodh.nl>
(cherry picked from commit b8c0d911ac5285e6be8967713271a51bdc5a936a)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
 drivers/md/bcache/super.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index cc55e08..11e976e 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -58,6 +58,7 @@ static wait_queue_head_t unregister_wait;
 struct workqueue_struct *bcache_wq;
 
 #define BTREE_MAX_PAGES		(256 * 1024 / PAGE_SIZE)
+#define BCACHE_MINORS		16 /* partition support */
 
 /* Superblock */
 
@@ -781,8 +782,10 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
 	if (minor < 0)
 		return minor;
 
+	minor *= BCACHE_MINORS;
+
 	if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
-	    !(d->disk = alloc_disk(1))) {
+	    !(d->disk = alloc_disk(BCACHE_MINORS))) {
 		ida_simple_remove(&bcache_minor, minor);
 		return -ENOMEM;
 	}
-- 
2.7.4