ppp: Reconstruct fragmented packets using frag lists instead of copying.

[paulus@samba.org: fixed a couple of bugs]

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 23 insertions, 16 deletions

diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 3d7a38eeacda..1d4fb348488f 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -2055,16 +2055,6 @@ ppp_mp_reconstruct(struct ppp *ppp)
                                 netdev_printk(KERN_DEBUG, ppp->dev,
                                               "PPP: reconstructed packet"
                                               " is too long (%d)\n", len);
-                        } else if (p == head) {
-                                /* fragment is complete packet - reuse skb */
-                                tail = p;
-                                skb = skb_get(p);
-                                break;
-                        } else if ((skb = dev_alloc_skb(len)) == NULL) {
-                                ++ppp->dev->stats.rx_missed_errors;
-                                netdev_printk(KERN_DEBUG, ppp->dev,
-                                              "PPP: no memory for "
-                                              "reconstructed packet");
                         } else {
                                 tail = p;
                                 break;
@@ -2097,16 +2087,33 @@ ppp_mp_reconstruct(struct ppp *ppp)
                         ppp_receive_error(ppp);
                 }
 
-                if (head != tail)
-                        /* copy to a single skb */
-                        for (p = head; p != tail->next; p = p->next)
-                                skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
+                skb = head;
+                if (head != tail) {
+                        struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
+                        p = skb_queue_next(list, head);
+                        __skb_unlink(skb, list);
+                        skb_queue_walk_from_safe(list, p, tmp) {
+                                __skb_unlink(p, list);
+                                *fragpp = p;
+                                p->next = NULL;
+                                fragpp = &p->next;
+
+                                skb->len += p->len;
+                                skb->data_len += p->len;
+                                skb->truesize += p->len;
+
+                                if (p == tail)
+                                        break;
+                        }
+                } else {
+                        __skb_unlink(skb, list);
+                }
+
                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
                 head = tail->next;
         }
 
-        /* Discard all the skbuffs that we have copied the data out of
-           or that we can't use. */
+        /* Discard all the skbuffs that we can't use. */
         while ((p = list->next) != head) {
                 __skb_unlink(p, list);
                 kfree_skb(p);