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authorIlan Tayari <ilant@mellanox.com>2017-04-19 21:26:07 +0300
committerDavid S. Miller <davem@davemloft.net>2017-04-21 13:30:29 -0400
commit43170c4e0ba709c79130c3fe5a41e66279950cd0 (patch)
treeb2ee11ce9dc26ae3649c22689427aef30bb0e4d8
parent918b70244f57920db8fcb5ae63e2d0c79b509821 (diff)
downloadlinux-43170c4e0ba709c79130c3fe5a41e66279950cd0.tar.bz2
gso: Validate assumption of frag_list segementation
Commit 07b26c9454a2 ("gso: Support partial splitting at the frag_list pointer") assumes that all SKBs in a frag_list (except maybe the last one) contain the same amount of GSO payload. This assumption is not always correct, resulting in the following warning message in the log: skb_segment: too many frags For example, mlx5 driver in Striding RQ mode creates some RX SKBs with one frag, and some with 2 frags. After GRO, the frag_list SKBs end up having different amounts of payload. If this frag_list SKB is then forwarded, the aforementioned assumption is violated. Validate the assumption, and fall back to software GSO if it not true. Change-Id: Ia03983f4a47b6534dd987d7a2aad96d54d46d212 Fixes: 07b26c9454a2 ("gso: Support partial splitting at the frag_list pointer") Signed-off-by: Ilan Tayari <ilant@mellanox.com> Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/skbuff.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 35c1e2460206..f86bf69cfb8d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3082,22 +3082,32 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
if (sg && csum && (mss != GSO_BY_FRAGS)) {
if (!(features & NETIF_F_GSO_PARTIAL)) {
struct sk_buff *iter;
+ unsigned int frag_len;
if (!list_skb ||
!net_gso_ok(features, skb_shinfo(head_skb)->gso_type))
goto normal;
- /* Split the buffer at the frag_list pointer.
- * This is based on the assumption that all
- * buffers in the chain excluding the last
- * containing the same amount of data.
+ /* If we get here then all the required
+ * GSO features except frag_list are supported.
+ * Try to split the SKB to multiple GSO SKBs
+ * with no frag_list.
+ * Currently we can do that only when the buffers don't
+ * have a linear part and all the buffers except
+ * the last are of the same length.
*/
+ frag_len = list_skb->len;
skb_walk_frags(head_skb, iter) {
+ if (frag_len != iter->len && iter->next)
+ goto normal;
if (skb_headlen(iter))
goto normal;
len -= iter->len;
}
+
+ if (len != frag_len)
+ goto normal;
}
/* GSO partial only requires that we trim off any excess that