[sheepdog] [PATCH v8 3/3] lib: correct a way of freeing sockfd_cache_entry

[Liu Yuan]

On Wed, Jul 31, 2013 at 04:11:48PM +0900, Hitoshi Mitake wrote:
> Previous implementation of the sockfd caching mechanism has two memory
> leaks. The leak is caused when sockfd_cache_destroy() and
> sockfd_cache_add_nolock() try to free a sockfd cache entry. They
> forget to free entry->fds.
> 
> This patch adds a new function, free_cache_entry() for safe freeing of
> sockfd cache entries. And let the above two functions to use it.
> 
> Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
> ---
>  lib/sockfd_cache.c |   11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/sockfd_cache.c b/lib/sockfd_cache.c
> index 98cea94..9a87ed9 100644
> --- a/lib/sockfd_cache.c
> +++ b/lib/sockfd_cache.c
> @@ -179,6 +179,13 @@ static inline void destroy_all_slots(struct sockfd_cache_entry *entry)
>  			close(entry->fds[i].fd);
>  }
>  
> +static void free_cache_entry(struct sockfd_cache_entry *entry)
> +{
> +	if (entry->fds)
> +		free(entry->fds);
> +	free(entry);
> +}

this is just a internal function and we know ->fds is always allocated and
even if ->fds == NULL, free(NULL) is valid. so if check is unnecessary. 

Thanks
Yuan