Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-omap-h63xx.git] / net / core / skbuff.c

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 0daf5c0e5b8df62c915490ce3f42f66f5e31b00b..366621610e76d5a91ae72522d38d0b60e3df45d9 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -200,7 +200,9 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
                goto nodata;
 
        /*
-        * See comment in sk_buff definition, just before the 'tail' member
+        * Only clear those fields we need to clear, not those that we will
+        * actually initialise below. Hence, don't put any more fields after
+        * the tail pointer in struct sk_buff!
         */
        memset(skb, 0, offsetof(struct sk_buff, tail));
        skb->truesize = size + sizeof(struct sk_buff);
@@ -277,6 +279,10 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
  */
 struct sk_buff *dev_alloc_skb(unsigned int length)
 {
+       /*
+        * There is more code here than it seems:
+        * __dev_alloc_skb is an inline
+        */
        return __dev_alloc_skb(length, GFP_ATOMIC);
 }
 EXPORT_SYMBOL(dev_alloc_skb);
@@ -896,6 +902,25 @@ unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
 }
 EXPORT_SYMBOL(skb_put);
 
+/**
+ *     skb_push - add data to the start of a buffer
+ *     @skb: buffer to use
+ *     @len: amount of data to add
+ *
+ *     This function extends the used data area of the buffer at the buffer
+ *     start. If this would exceed the total buffer headroom the kernel will
+ *     panic. A pointer to the first byte of the extra data is returned.
+ */
+unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
+{
+       skb->data -= len;
+       skb->len  += len;
+       if (unlikely(skb->data<skb->head))
+               skb_under_panic(skb, len, __builtin_return_address(0));
+       return skb->data;
+}
+EXPORT_SYMBOL(skb_push);
+
 /**
  *     skb_pull - remove data from the start of a buffer
  *     @skb: buffer to use
@@ -912,6 +937,22 @@ unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
 }
 EXPORT_SYMBOL(skb_pull);
 
+/**
+ *     skb_trim - remove end from a buffer
+ *     @skb: buffer to alter
+ *     @len: new length
+ *
+ *     Cut the length of a buffer down by removing data from the tail. If
+ *     the buffer is already under the length specified it is not modified.
+ *     The skb must be linear.
+ */
+void skb_trim(struct sk_buff *skb, unsigned int len)
+{
+       if (skb->len > len)
+               __skb_trim(skb, len);
+}
+EXPORT_SYMBOL(skb_trim);
+
 /* Trims skb to length len. It can change skb pointers.
  */
 
@@ -1251,12 +1292,14 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset,
 {
        unsigned int nr_pages = spd->nr_pages;
        unsigned int poff, plen, len, toff, tlen;
-       int headlen, seg;
+       int headlen, seg, error = 0;
 
        toff = *offset;
        tlen = *total_len;
-       if (!tlen)
+       if (!tlen) {
+               error = 1;
                goto err;
+       }
 
        /*
         * if the offset is greater than the linear part, go directly to
@@ -1298,7 +1341,8 @@ static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset,
                 * just jump directly to update and return, no point
                 * in going over fragments when the output is full.
                 */
-               if (spd_fill_page(spd, virt_to_page(p), plen, poff, skb))
+               error = spd_fill_page(spd, virt_to_page(p), plen, poff, skb);
+               if (error)
                        goto done;
 
                tlen -= plen;
@@ -1328,7 +1372,8 @@ map_frag:
                if (!plen)
                        break;
 
-               if (spd_fill_page(spd, f->page, plen, poff, skb))
+               error = spd_fill_page(spd, f->page, plen, poff, skb);
+               if (error)
                        break;
 
                tlen -= plen;
@@ -1341,7 +1386,10 @@ done:
                return 0;
        }
 err:
-       return 1;
+       /* update the offset to reflect the linear part skip, if any */
+       if (!error)
+               *offset = toff;
+       return error;
 }
 
 /*
@@ -1404,6 +1452,7 @@ done:
 
        if (spd.nr_pages) {
                int ret;
+               struct sock *sk = __skb->sk;
 
                /*
                 * Drop the socket lock, otherwise we have reverse
@@ -1414,9 +1463,9 @@ done:
                 * we call into ->sendpage() with the i_mutex lock held
                 * and networking will grab the socket lock.
                 */
-               release_sock(__skb->sk);
+               release_sock(sk);
                ret = splice_to_pipe(pipe, &spd);
-               lock_sock(__skb->sk);
+               lock_sock(sk);
                return ret;
        }
 
@@ -1821,7 +1870,7 @@ void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head
        unsigned long flags;
 
        spin_lock_irqsave(&list->lock, flags);
-       __skb_append(old, newsk, list);
+       __skb_queue_after(list, old, newsk);
        spin_unlock_irqrestore(&list->lock, flags);
 }
 
@@ -2186,8 +2235,8 @@ EXPORT_SYMBOL_GPL(skb_pull_rcsum);
  *     @features: features for the output path (see dev->features)
  *
  *     This function performs segmentation on the given skb.  It returns
- *     the segment at the given position.  It returns NULL if there are
- *     no more segments to generate, or when an error is encountered.
+ *     a pointer to the first in a list of new skbs for the segments.
+ *     In case of error it returns ERR_PTR(err).
  */
 struct sk_buff *skb_segment(struct sk_buff *skb, int features)
 {