3 files changed, 24 insertions, 8 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index cec0657d0d32..12e6fed73f8e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -568,8 +568,9 @@ extern struct sk_buff *skb_clone(struct sk_buff *skb,
                                  gfp_t priority);
 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
                                 gfp_t priority);
-extern struct sk_buff *pskb_copy(struct sk_buff *skb,
-                                 gfp_t gfp_mask);
+extern struct sk_buff *__pskb_copy(struct sk_buff *skb,
+                                 int headroom, gfp_t gfp_mask);
+
 extern int             pskb_expand_head(struct sk_buff *skb,
                                         int nhead, int ntail,
                                         gfp_t gfp_mask);
@@ -1799,6 +1800,12 @@ static inline dma_addr_t skb_frag_dma_map(struct device *dev,
                             frag->page_offset + offset, size, dir);
 }
 
+static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
+                                        gfp_t gfp_mask)
+{
+        return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
+}
+
 /**
  *      skb_clone_writable - is the header of a clone writable
  *      @skb: buffer to check
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 678ae4e783aa..fd3646209b65 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -840,8 +840,9 @@ struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
 EXPORT_SYMBOL(skb_copy);
 
 /**
- *      pskb_copy       -       create copy of an sk_buff with private head.
+ *      __pskb_copy     -       create copy of an sk_buff with private head.
  *      @skb: buffer to copy
+ *      @headroom: headroom of new skb
  *      @gfp_mask: allocation priority
  *
  *      Make a copy of both an &sk_buff and part of its data, located
@@ -852,16 +853,16 @@ EXPORT_SYMBOL(skb_copy);
  *      The returned buffer has a reference count of 1.
  */
 
-struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
+struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask)
 {
-        unsigned int size = skb_end_pointer(skb) - skb->head;
+        unsigned int size = skb_headlen(skb) + headroom;
         struct sk_buff *n = alloc_skb(size, gfp_mask);
 
         if (!n)
                 goto out;
 
         /* Set the data pointer */
-        skb_reserve(n, skb_headroom(skb));
+        skb_reserve(n, headroom);
         /* Set the tail pointer and length */
         skb_put(n, skb_headlen(skb));
         /* Copy the bytes */
@@ -897,7 +898,7 @@ struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
 out:
         return n;
 }
-EXPORT_SYMBOL(pskb_copy);
+EXPORT_SYMBOL(__pskb_copy);
 
 /**
  *      pskb_expand_head - reallocate header of &sk_buff
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 58f69acd3d22..50788d67bdb7 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2147,7 +2147,15 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
          */
         TCP_SKB_CB(skb)->when = tcp_time_stamp;
 
-        err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
+        /* make sure skb->data is aligned on arches that require it */
+        if (unlikely(NET_IP_ALIGN && ((unsigned long)skb->data & 3))) {
+                struct sk_buff *nskb = __pskb_copy(skb, MAX_TCP_HEADER,
+                                                   GFP_ATOMIC);
+                err = nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
+                             -ENOBUFS;
+        } else {
+                err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
+        }
 
         if (err == 0) {
                 /* Update global TCP statistics. */