Re: [PATCH] flex_array: add helpers to get and put to make pointers easy to use

[Joe Perches <joe@perches.com>]

On Tue, 2010-08-03 at 15:36 -0400, Eric Paris wrote:
> Getting and putting arrays of pointers with flex arrays is a PITA.  You
> have to remember to pass &ptr to the _put and you have to do weird and
> wacky casting to get the ptr back from the _get.  Add two functions
> flex_array_get_ptr() and flex_array_put_ptr() to handle all of the magic.
> 
> Signed-off-by: Eric Paris <eparis@redhat.com>
> ---
> 
>  include/linux/flex_array.h |    6 ++++++
>  lib/flex_array.c           |   25 ++++++++++++++++++++++++-
>  2 files changed, 30 insertions(+), 1 deletions(-)
> 
> diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h
> index 1d747f7..f4e4eb2 100644
> --- a/include/linux/flex_array.h
> +++ b/include/linux/flex_array.h
> @@ -70,4 +70,10 @@ int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
>  void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
>  int flex_array_shrink(struct flex_array *fa);
>  
> +#define flex_array_put_ptr(fa, nr, src, gfp)	({						\
> +						 void *_src = (src);				\
> +						 flex_array_put((fa), (nr), &_src, (gfp));	\
> +						})

Might be nicer to use fewer indents.
Isn't this equivalent?

#define flex_array_put_ptr(fa, nr, src, gfp)			\
	flex_array_put(fa, nr, &(void *)(src), gfp)