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bcache: Add comments for blkdev_put() in registration code path

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Add comments to explain why in register_bcache() blkdev_put() won't
be called in two location. Add comments to explain why blkdev_put()
must be called in register_cache() when cache_alloc() failed.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Coly Li 2019-04-25 00:48:38 +08:00 committed by Jens Axboe
parent 88c12d42d2
commit bb6d355c2a
1 changed files with 8 additions and 0 deletions
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8
drivers/md/bcache/super.c
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@ -2189,6 +2189,12 @@ static int register_cache(struct cache_sb *sb, struct page *sb_page,
ret = cache_alloc(ca); ret = cache_alloc(ca);
if (ret != 0) { if (ret != 0) {
/*
* If we failed here, it means ca->kobj is not initialized yet,
* kobject_put() won't be called and there is no chance to
* call blkdev_put() to bdev in bch_cache_release(). So we
* explicitly call blkdev_put() here.
*/
blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
if (ret == -ENOMEM) if (ret == -ENOMEM)
err = "cache_alloc(): -ENOMEM"; err = "cache_alloc(): -ENOMEM";
@ -2329,6 +2335,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
mutex_lock(&bch_register_lock); mutex_lock(&bch_register_lock);
ret = register_bdev(sb, sb_page, bdev, dc); ret = register_bdev(sb, sb_page, bdev, dc);
mutex_unlock(&bch_register_lock); mutex_unlock(&bch_register_lock);
/* blkdev_put() will be called in cached_dev_free() */
if (ret < 0) if (ret < 0)
goto err; goto err;
} else { } else {
@ -2337,6 +2344,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
if (!ca) if (!ca)
goto err_close; goto err_close;
/* blkdev_put() will be called in bch_cache_release() */
if (register_cache(sb, sb_page, bdev, ca) != 0) if (register_cache(sb, sb_page, bdev, ca) != 0)
goto err; goto err;
} }