* Re: [PATCH net] tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS
[not found] <1608810533-8308-1-git-send-email-wangyunjian@huawei.com>
@ 2020-12-24 15:56 ` Willem de Bruijn
2020-12-27 11:18 ` Michael S. Tsirkin
2020-12-27 9:39 ` Michael S. Tsirkin
1 sibling, 1 reply; 3+ messages in thread
From: Willem de Bruijn @ 2020-12-24 15:56 UTC (permalink / raw)
To: wangyunjian
Cc: Willem de Bruijn, Michael S. Tsirkin, Network Development,
Lilijun (Jerry), virtualization, xudingke, huangbin (J),
chenchanghu
On Thu, Dec 24, 2020 at 6:51 AM wangyunjian <wangyunjian@huawei.com> 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.
>
> 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>
It might be good to explain why the distinction matters: one denotes a
transient failure that the caller (specifically vhost_net) can retry,
the other a persistent failure due to bad packet geometry that should
be dropped.
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH net] tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS
[not found] <1608810533-8308-1-git-send-email-wangyunjian@huawei.com>
2020-12-24 15:56 ` [PATCH net] tun: fix return value when the number of iovs exceeds MAX_SKB_FRAGS Willem de Bruijn
@ 2020-12-27 9:39 ` Michael S. Tsirkin
1 sibling, 0 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2020-12-27 9:39 UTC (permalink / raw)
To: wangyunjian
Cc: willemdebruijn.kernel, netdev, jerry.lilijun, virtualization,
xudingke, brian.huangbin, chenchanghu
On Thu, Dec 24, 2020 at 07:48:53PM +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.
>
> Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 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] 3+ messages in thread