Re: [PATCH 1/5] rbd: define rbd_assert()

[Josh Durgin <josh.durgin@inktank.com>]

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

On 09/07/2012 06:39 AM, Alex Elder wrote:
> Define rbd_assert() and use it in place of various BUG_ON() calls
> now present in the code.  By default assertion checking is enabled;
> we want to do this differently at some point.
>
> Signed-off-by: Alex Elder <elder@inktank.com>
> ---
>   drivers/block/rbd.c |   35 ++++++++++++++++++++++++++---------
>   1 file changed, 26 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 7ba70c4..d84b534 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -41,6 +41,8 @@
>
>   #include "rbd_types.h"
>
> +#define RBD_DEBUG	/* Activate rbd_assert() calls */
> +
>   /*
>    * The basic unit of block I/O is a sector.  It is interpreted in a
>    * number of contexts in Linux (blk, bio, genhd), but the default is
> @@ -232,6 +234,18 @@ static struct device rbd_root_dev = {
>   	.release =      rbd_root_dev_release,
>   };
>
> +#ifdef RBD_DEBUG
> +#define rbd_assert(expr)						\
> +		if (unlikely(!(expr))) {				\
> +			printk(KERN_ERR "\nAssertion failure in %s() "	\
> +						"at line %d:\n\n"	\
> +					"\trbd_assert(%s);\n\n",	\
> +					__func__, __LINE__, #expr);	\
> +			BUG();						\
> +		}
> +#else /* !RBD_DEBUG */
> +#  define rbd_assert(expr)	((void) 0)
> +#endif /* !RBD_DEBUG */
>
>   static struct device *rbd_get_dev(struct rbd_device *rbd_dev)
>   {
> @@ -406,7 +420,8 @@ static int parse_rbd_opts_token(char *c, void *private)
>   		rbd_opts->read_only = false;
>   		break;
>   	default:
> -		BUG_ON(token);
> +		rbd_assert(false);
> +		break;
>   	}
>   	return 0;
>   }
> @@ -705,7 +720,7 @@ static u64 rbd_segment_length(struct rbd_device
> *rbd_dev,
>
>   	offset &= segment_size - 1;
>
> -	BUG_ON(length > U64_MAX - offset);
> +	rbd_assert(length <= U64_MAX - offset);
>   	if (offset + length > segment_size)
>   		length = segment_size - offset;
>
> @@ -842,7 +857,7 @@ static struct bio *bio_chain_clone(struct bio **old,
> struct bio **next,
>   		total += tmp->bi_size;
>   	}
>
> -	BUG_ON(total < len);
> +	rbd_assert(total == len);
>
>   	*old = old_chain;
>
> @@ -1101,7 +1116,7 @@ static int rbd_req_sync_op(struct rbd_device *rbd_dev,
>   	struct page **pages;
>   	int num_pages;
>
> -	BUG_ON(ops == NULL);
> +	rbd_assert(ops != NULL);
>
>   	num_pages = calc_pages_for(ofs , len);
>   	pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
> @@ -1163,7 +1178,7 @@ static int rbd_do_op(struct request *rq,
>   	/* we've taken care of segment sizes earlier when we
>   	   cloned the bios. We should never have a segment
>   	   truncated at this point */
> -	BUG_ON(seg_len < len);
> +	rbd_assert(seg_len == len);
>
>   	ret = rbd_do_request(rq, rbd_dev, snapc, snapid,
>   			     seg_name, seg_ofs, seg_len,
> @@ -2186,7 +2201,7 @@ static int __rbd_init_snaps_header(struct
> rbd_device *rbd_dev)
>   					     : CEPH_NOSNAP;
>   		snap = links != head ? list_entry(links, struct rbd_snap, node)
>   				     : NULL;
> -		BUG_ON(snap && snap->id == CEPH_NOSNAP);
> +		rbd_assert(!snap || snap->id != CEPH_NOSNAP);
>
>   		if (snap_id == CEPH_NOSNAP || (snap && snap->id > snap_id)) {
>   			struct list_head *next = links->next;
> @@ -2222,8 +2237,9 @@ static int __rbd_init_snaps_header(struct
> rbd_device *rbd_dev)
>   		} else {
>   			/* Already have this one */
>
> -			BUG_ON(snap->size != rbd_dev->header.snap_sizes[index]);
> -			BUG_ON(strcmp(snap->name, snap_name));
> +			rbd_assert(snap->size ==
> +					rbd_dev->header.snap_sizes[index]);
> +			rbd_assert(!strcmp(snap->name, snap_name));
>
>   			/* Done with this list entry; advance */
>
> @@ -2313,7 +2329,7 @@ static void rbd_id_put(struct rbd_device *rbd_dev)
>   	int rbd_id = rbd_dev->dev_id;
>   	int max_id;
>
> -	BUG_ON(rbd_id < 1);
> +	rbd_assert(rbd_id > 0);
>
>   	spin_lock(&rbd_dev_list_lock);
>   	list_del_init(&rbd_dev->node);
> @@ -2705,6 +2721,7 @@ static ssize_t rbd_remove(struct bus_type *bus,
>
>   done:
>   	mutex_unlock(&ctl_mutex);
> +
>   	return ret;
>   }
>