Re: [PATCH 06/12] sunrpc/cache: avoid variable over-loading in cache_defer_req

["J. Bruce Fields" <bfields@fieldses.org>]

On Tue, Aug 04, 2009 at 03:22:39PM +1000, NeilBrown wrote:
> In cache_defer_req, 'dreq' is used for two significantly different
> values that happen to be of the same type.
> 
> This is both confusing, and make it hard to extend the range of one of
> the values as we will in the next patch.
> So introduce 'discard' to take one of the values.
> 
> Signed-off-by: NeilBrown <neilb@suse.de>
> ---
> 
>  net/sunrpc/cache.c |   14 +++++++-------
>  1 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index 2f19463..4892c5c 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -561,7 +561,7 @@ static int cache_defer_cnt;
>  
>  static int cache_defer_req(struct cache_req *req, struct cache_head *item)
>  {
> -	struct cache_deferred_req *dreq;
> +	struct cache_deferred_req *dreq, *discard;
>  	int hash = DFR_HASH(item);
>  
>  	if (cache_defer_cnt >= DFR_MAX) {
> @@ -586,20 +586,20 @@ static int cache_defer_req(struct cache_req *req, struct cache_head *item)
>  	list_add(&dreq->hash, &cache_defer_hash[hash]);
>  
>  	/* it is in, now maybe clean up */
> -	dreq = NULL;
> +	discard = NULL;
>  	if (++cache_defer_cnt > DFR_MAX) {
> -		dreq = list_entry(cache_defer_list.prev,
> -				  struct cache_deferred_req, recent);
> +		discard = list_entry(cache_defer_list.prev,
> +				     struct cache_deferred_req, recent);
>  		list_del_init(&dreq->recent);
>  		list_del_init(&dreq->hash);

Shouldn't these two "dreq"'s be "discard"'s as well?

--b.

>  		cache_defer_cnt--;
>  	}
>  	spin_unlock(&cache_defer_lock);
>  
> -	if (dreq) {
> +	if (discard)
>  		/* there was one too many */
> -		dreq->revisit(dreq, 1);
> -	}
> +		discard->revisit(discard, 1);
> +
>  	if (!test_bit(CACHE_PENDING, &item->flags)) {
>  		/* must have just been validated... */
>  		cache_revisit_request(item);
> 
>