Re: [PATCH 1/2] udp: fix gso_segs calculations

From: Josh Hunt <johunt@akamai.com>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	Alexander Duyck <alexander.duyck@gmail.com>
Cc: David Miller <davem@davemloft.net>,
	Netdev <netdev@vger.kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	"Duyck, Alexander H" <alexander.h.duyck@intel.com>
Subject: Re: [PATCH 1/2] udp: fix gso_segs calculations
Date: Tue, 1 Oct 2019 07:31:59 -0700	[thread overview]
Message-ID: <c56ce4ea-f416-163e-80ea-eaefea264fa8@akamai.com> (raw)
In-Reply-To: <CA+FuTSdkBpKtm48maiTWrRDuW0_ntvpkgXA_TvYZ6uOhf06duw@mail.gmail.com>

On 10/1/19 5:12 AM, Willem de Bruijn wrote:
> On Mon, Sep 30, 2019 at 7:51 PM Alexander Duyck
> <alexander.duyck@gmail.com> wrote:
>>
>> On Mon, Sep 30, 2019 at 3:15 PM Josh Hunt <johunt@akamai.com> wrote:
>>>
>>> Commit dfec0ee22c0a ("udp: Record gso_segs when supporting UDP segmentation offload")
>>> added gso_segs calculation, but incorrectly got sizeof() the pointer and
>>> not the underlying data type. It also does not account for v6 UDP GSO segs.
>>>
>>> Fixes: dfec0ee22c0a ("udp: Record gso_segs when supporting UDP segmentation offload")
>>> Signed-off-by: Josh Hunt <johunt@akamai.com>
>>> ---
>>>   net/ipv4/udp.c | 2 +-
>>>   net/ipv6/udp.c | 2 ++
>>>   2 files changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
>>> index cf755156a684..be98d0b8f014 100644
>>> --- a/net/ipv4/udp.c
>>> +++ b/net/ipv4/udp.c
>>> @@ -856,7 +856,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
>>>
>>>                  skb_shinfo(skb)->gso_size = cork->gso_size;
>>>                  skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
>>> -               skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(uh),
>>> +               skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(*uh),
>>>                                                           cork->gso_size);
>>>                  goto csum_partial;
>>>          }
>>> diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
>>> index aae4938f3dea..eb9a9934ac05 100644
>>> --- a/net/ipv6/udp.c
>>> +++ b/net/ipv6/udp.c
>>> @@ -1143,6 +1143,8 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
>>>
>>>                  skb_shinfo(skb)->gso_size = cork->gso_size;
>>>                  skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
>>> +               skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(*uh),
>>> +                                                        cork->gso_size);
>>>                  goto csum_partial;
>>>          }
>>>
>>
>> Fix looks good to me.
>>
>> You might also want to add the original commit since you are also
>> addressing IPv6 changes which are unrelated to my commit that your
>> referenced:
>> Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT")
>>
>> Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> 
> Acked-by: Willem de Bruijn <willemb@google.com>
> 
> If resending, please target net: [PATCH net v2]
> 

Thanks Willem. Yeah I should have targeted net originally. Will spin a v2.

Thanks!
Josh