Re: [RFC PATCH v2 09/16] bcache: add error check for calling register_bdev()

[Hannes Reinecke <hare@xxxxxxx>]

On 4/19/19 6:05 PM, Coly Li wrote:
> This patch adds return value to register_bdev(). Then if failure happens
> inside register_bdev(), its caller register_bcache() may detect and
> handle the failure more properly.
>
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> ---
>   drivers/md/bcache/super.c | 16 ++++++++++------
>   1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 400af446c372..a435c506edba 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1281,7 +1281,7 @@ static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
>   
>   /* Cached device - bcache superblock */
>   
> -static void register_bdev(struct cache_sb *sb, struct page *sb_page,
> +static int register_bdev(struct cache_sb *sb, struct page *sb_page,
>   				 struct block_device *bdev,
>   				 struct cached_dev *dc)
>   {
> @@ -1319,10 +1319,11 @@ static void register_bdev(struct cache_sb *sb, struct page *sb_page,
>   	    BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
>   		bch_cached_dev_run(dc);
>   
> -	return;
> +	return 0;
>   err:
>   	pr_notice("error %s: %s", dc->backing_dev_name, err);
>   	bcache_device_stop(&dc->disk);
> +	return -EIO;
>   }
>   
>   /* Flash only volumes */
> @@ -2273,7 +2274,7 @@ static bool bch_is_open(struct block_device *bdev)
>   static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>   			       const char *buffer, size_t size)
>   {
> -	ssize_t ret = size;
> +	ssize_t ret = -EINVAL;
>   	const char *err = "cannot allocate memory";
>   	char *path = NULL;
>   	struct cache_sb *sb = NULL;
> @@ -2307,7 +2308,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>   			if (!IS_ERR(bdev))
>   				bdput(bdev);
>   			if (attr == &ksysfs_register_quiet)
> -				goto out;
> +				goto quiet_out;
>   		}
>   		goto err;
>   	}
> @@ -2328,8 +2329,10 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>   			goto err_close;
>   
>   		mutex_lock(&bch_register_lock);
> -		register_bdev(sb, sb_page, bdev, dc);
> +		ret = register_bdev(sb, sb_page, bdev, dc);
>   		mutex_unlock(&bch_register_lock);
> +		if (ret < 0)
> +			goto err;
>   	} else {
>   		struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
>   
> @@ -2339,6 +2342,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>   		if (register_cache(sb, sb_page, bdev, ca) != 0)
>   			goto err;
>   	}
> +quiet_out:
> +	ret = size;
>   out:
>   	if (sb_page)
>   		put_page(sb_page);
> @@ -2351,7 +2356,6 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>   	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
>   err:
>   	pr_info("error %s: %s", path, err);
> -	ret = -EINVAL;
>   	goto out;
>   }
>   
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@xxxxxxx			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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