On 9/30/19 4:51 PM, Alexander Duyck wrote:

On Mon, Sep 30, 2019 at 3:15 PM Josh Hunt [off-list ref] wrote:

quoted

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 <redacted>
---
  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 <redacted>

Thanks for the review Alex. I will make those changes and spin a v2.

Thanks!
Josh