netdev - Re: [PATCH 2/18] gdm72xx: Move away from NLMSG

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Date:	Wed, 27 Jun 2012 13:07:11 +0200
From:	Javier Martinez Canillas <martinez.javier@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH 2/18] gdm72xx: Move away from NLMSG_PUT().

On Wed, Jun 27, 2012 at 7:02 AM, David Miller <davem@...emloft.net> wrote:
>
> And use nlmsg_data() while we're here too.
>
> Signed-off-by: David S. Miller <davem@...emloft.net>
> ---
>  drivers/staging/gdm72xx/netlink_k.c |   10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/gdm72xx/netlink_k.c b/drivers/staging/gdm72xx/netlink_k.c
> index 292af0f..d0cb48a 100644
> --- a/drivers/staging/gdm72xx/netlink_k.c
> +++ b/drivers/staging/gdm72xx/netlink_k.c
> @@ -127,8 +127,12 @@ int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
>        }
>
>        seq++;
> -       nlh = NLMSG_PUT(skb, 0, seq, type, len);
> -       memcpy(NLMSG_DATA(nlh), msg, len);
> +       nlh = nlmsg_put(skb, 0, seq, type, len, 0);
> +       if (!nlh) {
> +               kfree_skb(skb);
> +               return -EMSGSIZE;
> +       }
> +       memcpy(nlmsg_data(nlh), msg, len);
>
>        NETLINK_CB(skb).pid = 0;
>        NETLINK_CB(skb).dst_group = 0;
> @@ -144,7 +148,5 @@ int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
>                }
>                ret = 0;
>        }
> -
> -nlmsg_failure:
>        return ret;
>  }
> --
> 1.7.10.2
>
> --
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Hi David,

This also solves an skb memory leak since the sk_buff was allocated
before the NLMSG_PUT() macro and not  freed after jumping to the
nlmsg_failure label. I posted a similar patch before:

http://www.spinics.net/lists/linux-driver-devel/msg25756.html

and is already on linux-next with commitid:

2da049bd5f9b0dbd688519fdb6688a4895fe8395 staging: gdm72xx: fix an skb
memory leak

Best regards,
Javier
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