bpf: try harder on clones when writing into skb

[pandora-kernel.git] / include / linux / skbuff.h

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d0c9e6d..2af31eb 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1377,6 +1377,30 @@ static inline void skb_reserve(struct sk_buff *skb, int len)
        skb->tail += len;
 }
 
+/**
+ *     skb_tailroom_reserve - adjust reserved_tailroom
+ *     @skb: buffer to alter
+ *     @mtu: maximum amount of headlen permitted
+ *     @needed_tailroom: minimum amount of reserved_tailroom
+ *
+ *     Set reserved_tailroom so that headlen can be as large as possible but
+ *     not larger than mtu and tailroom cannot be smaller than
+ *     needed_tailroom.
+ *     The required headroom should already have been reserved before using
+ *     this function.
+ */
+static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
+                                       unsigned int needed_tailroom)
+{
+       SKB_LINEAR_ASSERT(skb);
+       if (mtu < skb_tailroom(skb) - needed_tailroom)
+               /* use at most mtu */
+               skb->reserved_tailroom = skb_tailroom(skb) - mtu;
+       else
+               /* use up to all available space */
+               skb->reserved_tailroom = needed_tailroom;
+}
+
 static inline void skb_reset_mac_len(struct sk_buff *skb)
 {
        skb->mac_len = skb->network_header - skb->mac_header;
@@ -1902,6 +1926,13 @@ static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len
               skb_headroom(skb) + len <= skb->hdr_len;
 }
 
+static inline int skb_try_make_writable(struct sk_buff *skb,
+                                       unsigned int write_len)
+{
+       return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
+              pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
+}
+
 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
                            int cloned)
 {
@@ -2134,8 +2165,7 @@ extern int               skb_copy_datagram_iovec(const struct sk_buff *from,
                                               int size);
 extern int            skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
                                                        int hlen,
-                                                       struct iovec *iov,
-                                                       int len);
+                                                       struct iovec *iov);
 extern int            skb_copy_datagram_from_iovec(struct sk_buff *skb,
                                                    int offset,
                                                    const struct iovec *from,