* Re: [PATCH net v2] tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS
[not found] <1608864736-24332-1-git-send-email-wangyunjian@huawei.com>
@ 2020-12-25 6:18 ` Jason Wang
2020-12-27 9:40 ` Michael S. Tsirkin
1 sibling, 0 replies; 2+ messages in thread
From: Jason Wang @ 2020-12-25 6:18 UTC (permalink / raw)
To: wangyunjian, netdev, mst, willemdebruijn.kernel
Cc: xudingke, brian.huangbin, jerry.lilijun, chenchanghu,
virtualization
On 2020/12/25 上午10:52, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian@huawei.com>
>
> Currently the tun_napi_alloc_frags() function returns -ENOMEM when the
> number of iovs exceeds MAX_SKB_FRAGS + 1. However this is inappropriate,
> we should use -EMSGSIZE instead of -ENOMEM.
>
> The following distinctions are matters:
> 1. the caller need to drop the bad packet when -EMSGSIZE is returned,
> which means meeting a persistent failure.
> 2. the caller can try again when -ENOMEM is returned, which means
> meeting a transient failure.
>
> Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> Acked-by: Willem de Bruijn <willemb@google.com>
> ---
> v2:
> * update commit log suggested by Willem de Bruijn
> ---
> drivers/net/tun.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 2dc1988a8973..15c6dd7fb04c 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1365,7 +1365,7 @@ static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
> int i;
>
> if (it->nr_segs > MAX_SKB_FRAGS + 1)
> - return ERR_PTR(-ENOMEM);
> + return ERR_PTR(-EMSGSIZE);
>
> local_bh_disable();
> skb = napi_get_frags(&tfile->napi);
Acked-by: Jason Wang <jasowang@redhat.com>
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^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH net v2] tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS
[not found] <1608864736-24332-1-git-send-email-wangyunjian@huawei.com>
2020-12-25 6:18 ` [PATCH net v2] tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS Jason Wang
@ 2020-12-27 9:40 ` Michael S. Tsirkin
1 sibling, 0 replies; 2+ messages in thread
From: Michael S. Tsirkin @ 2020-12-27 9:40 UTC (permalink / raw)
To: wangyunjian
Cc: willemdebruijn.kernel, netdev, jerry.lilijun, virtualization,
xudingke, brian.huangbin, chenchanghu
On Fri, Dec 25, 2020 at 10:52:16AM +0800, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian@huawei.com>
>
> Currently the tun_napi_alloc_frags() function returns -ENOMEM when the
> number of iovs exceeds MAX_SKB_FRAGS + 1. However this is inappropriate,
> we should use -EMSGSIZE instead of -ENOMEM.
>
> The following distinctions are matters:
> 1. the caller need to drop the bad packet when -EMSGSIZE is returned,
> which means meeting a persistent failure.
> 2. the caller can try again when -ENOMEM is returned, which means
> meeting a transient failure.
>
> Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> v2:
> * update commit log suggested by Willem de Bruijn
> ---
> drivers/net/tun.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 2dc1988a8973..15c6dd7fb04c 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1365,7 +1365,7 @@ static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
> int i;
>
> if (it->nr_segs > MAX_SKB_FRAGS + 1)
> - return ERR_PTR(-ENOMEM);
> + return ERR_PTR(-EMSGSIZE);
>
> local_bh_disable();
> skb = napi_get_frags(&tfile->napi);
> --
> 2.23.0
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^ permalink raw reply [flat|nested] 2+ messages in thread