Re: [PATCH] V4L: fix retval in vivi driver for more than one device

[Mauro Carvalho Chehab]

This patch is not 100% OK, for some reasons:

1) since ret won't be initialized anymore, it will generate compilation
   warnings;

2) with the current code, if you ask to allocate, let's say, 3 virtual
   drivers, and the second or the third fails, you'll still have one
   allocated. With your change, you'll de-allocate even the ones that
   succeeded. IMO, the better is to allow using the ones that succeeded.

That's said, I can see other issues on the current vivi.c code:

1) what happens if someone uses n_dev=0? It will return a wrong error
   code.

2) there are still some cases where the driver allocates less devices than
   requested, but it will fail to register, and all stuff will be
   de-allocated;

3) what if n_dev is a big number? Currently, i think videodev will allow
   you to register up to 32 video devices of this type, even if you have
   memory for more, due to some limits inside videodev, and due to the
   number of minors allocated for V4L.  IMO, the driver should allocate up
   to the maximum allowed devices by videodev, and let users use they.

Anyway, thanks for your patch. For sure we need to do some fixes here. 
I'll try to address all those stuff into a patch.

Cheers,
Mauro.


On Fri, 22 Aug 2008, Henne wrote:

> From: Henrik Kretzschmar <henne@xxxxxxxxxxxxxxxx>
> Signed-off-by: Henrik Kretzschmar <henne@xxxxxxxxxxxxxxxx>
>
> The variable ret should be set for each device to -ENOMEM, not only the 
> first.
>
> diff --git a/drivers/media/video/vivi.c b/drivers/media/video/vivi.c
> index 3518af0..d739b59 100644
> --- a/drivers/media/video/vivi.c
> +++ b/drivers/media/video/vivi.c
> @@ -1106,11 +1106,12 @@ static struct video_device vivi_template = {
>
> static int __init vivi_init(void)
> {
> -	int ret = -ENOMEM, i;
> +	int ret, i;
> 	 struct vivi_dev *dev;
> 	 struct video_device *vfd;
>
> 	for (i = 0; i < n_devs; i++) {
> +		ret = -ENOMEM;
> 		 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> 		 if (NULL == dev)
> 			 break;

--
Cheers,
Mauro Carvalho Chehab
http://linuxtv.org
mchehab@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/