datapath: Orphan frags in skb_zerocopy and handle errors

[cascardo/ovs.git] / datapath / linux / compat / skbuff-openvswitch.c

diff --git a/datapath/linux/compat/skbuff-openvswitch.c b/datapath/linux/compat/skbuff-openvswitch.c
index ddd7bc8..96c27d0 100644 (file)
--- a/datapath/linux/compat/skbuff-openvswitch.c
+++ b/datapath/linux/compat/skbuff-openvswitch.c
@@ -61,25 +61,31 @@ skb_zerocopy_headlen(const struct sk_buff *from)
  *
  *     The `hlen` as calculated by skb_zerocopy_headlen() specifies the
  *     headroom in the `to` buffer.
+ *
+ *     Return value:
+ *     0: everything is OK
+ *     -ENOMEM: couldn't orphan frags of @from due to lack of memory
+ *     -EFAULT: skb_copy_bits() found some problem with skb geometry
  */
-void
-skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
+int
+skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
 {
        int i, j = 0;
        int plen = 0; /* length of skb->head fragment */
+       int ret;
        struct page *page;
        unsigned int offset;
 
        BUG_ON(!head_frag(from) && !hlen);
 
        /* dont bother with small payloads */
-       if (len <= skb_tailroom(to)) {
-               skb_copy_bits(from, 0, skb_put(to, len), len);
-               return;
-       }
+       if (len <= skb_tailroom(to))
+               return skb_copy_bits(from, 0, skb_put(to, len), len);
 
        if (hlen) {
-               skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+               ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+               if (unlikely(ret))
+                       return ret;
                len -= hlen;
        } else {
                plen = min_t(int, skb_headlen(from), len);
@@ -97,6 +103,11 @@ skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
        to->len += len + plen;
        to->data_len += len + plen;
 
+       if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
+               skb_tx_error(from);
+               return -ENOMEM;
+       }
+
        for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
                if (!len)
                        break;
@@ -107,5 +118,7 @@ skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
                j++;
        }
        skb_shinfo(to)->nr_frags = j;
+
+       return 0;
 }
 #endif