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authorEric Dumazet <edumazet@google.com>2014-10-03 20:59:19 -0700
committerDavid S. Miller <davem@davemloft.net>2014-10-06 00:37:30 -0400
commitbec3cfdca36bf43cfa3751ad7b56db1a307e0760 (patch)
treed9c2d8352b0cc41d43dc23b7a7eafdac6758aeb3 /net
parent45d9cc7c609680e921060d3eb4e399043eb5e4be (diff)
net: skb_segment() provides list head and tail
Its unfortunate we have to walk again skb list to find the tail after segmentation, even if data is probably hot in cpu caches. skb_segment() can store the tail of the list into segs->prev, and validate_xmit_skb_list() can immediately get the tail. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c27
-rw-r--r--net/core/skbuff.c5
2 files changed, 20 insertions, 12 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 1a90530f83f..7d5691cc1f4 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2724,22 +2724,25 @@ struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *d
{
struct sk_buff *next, *head = NULL, *tail;
- while (skb) {
+ for (; skb != NULL; skb = next) {
next = skb->next;
skb->next = NULL;
+
+ /* in case skb wont be segmented, point to itself */
+ skb->prev = skb;
+
skb = validate_xmit_skb(skb, dev);
- if (skb) {
- struct sk_buff *end = skb;
+ if (!skb)
+ continue;
- while (end->next)
- end = end->next;
- if (!head)
- head = skb;
- else
- tail->next = skb;
- tail = end;
- }
- skb = next;
+ if (!head)
+ head = skb;
+ else
+ tail->next = skb;
+ /* If skb was segmented, skb->prev points to
+ * the last segment. If not, it still contains skb.
+ */
+ tail = skb->prev;
}
return head;
}
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9a423e2c576..7b3df0d518a 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3083,6 +3083,11 @@ perform_csum_check:
}
} while ((offset += len) < head_skb->len);
+ /* Some callers want to get the end of the list.
+ * Put it in segs->prev to avoid walking the list.
+ * (see validate_xmit_skb_list() for example)
+ */
+ segs->prev = tail;
return segs;
err: