From: Dongbo Cao cdbdyx@163.com
mainline inclusion from mainline-4.20-rc1 commit 3a646fd77684dd5fbe20748bb04e12077bbecddc category: backport
when the nbuckets of cache device is smaller than 1024, making cache device will trigger BUG_ON in kernel, add a condition to avoid this.
Reported-by: nitroxis n@nxs.re Signed-off-by: Dongbo Cao cdbdyx@163.com Signed-off-by: Coly Li colyli@suse.de Signed-off-by: Jens Axboe axboe@kernel.dk --- drivers/md/bcache/super.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 1d6b74854bc8..b72459d340cf 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -2065,6 +2065,11 @@ static int cache_alloc(struct cache *ca) */ btree_buckets = ca->sb.njournal_buckets ?: 8; free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; + if (!free) { + ret = -EPERM; + err = "ca->sb.nbuckets is too small"; + goto err_free; + }
if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL)) { @@ -2142,6 +2147,7 @@ static int cache_alloc(struct cache *ca) err_prio_alloc: free_fifo(&ca->free[RESERVE_BTREE]); err_btree_alloc: +err_free: module_put(THIS_MODULE); if (err) pr_notice("error %s: %s", ca->cache_dev_name, err); @@ -2171,6 +2177,8 @@ static int register_cache(struct cache_sb *sb, struct page *sb_page, blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); if (ret == -ENOMEM) err = "cache_alloc(): -ENOMEM"; + else if (ret == -EPERM) + err = "cache_alloc(): cache device is too small"; else err = "cache_alloc(): unknown error"; goto err;