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authorDavid S. Miller <davem@sunset.davemloft.net>2007-04-27 15:21:23 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-27 15:21:23 -0700
commit1a028e50729b85d0a038fad13daf0ee201a37454 (patch)
treea4ffbf7c5476203e1db51b4bd9d076c69d772697 /net/core/user_dma.c
parent50f732ee63b91eb08a29974b36bd63e1150bb642 (diff)
[NET]: Revert sk_buff walker cleanups.
This reverts eefa3906283a2b60a6d02a2cda593a7d7d7946c5 The simplification made in that change works with the assumption that the 'offset' parameter to these functions is always positive or zero, which is not true. It can be and often is negative in order to access SKB header values in front of skb->data. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/user_dma.c')
-rw-r--r--net/core/user_dma.c25
1 files changed, 16 insertions, 9 deletions
diff --git a/net/core/user_dma.c b/net/core/user_dma.c
index 89241cdeea3f..0ad1cd57bc39 100644
--- a/net/core/user_dma.c
+++ b/net/core/user_dma.c
@@ -49,8 +49,8 @@ int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
struct sk_buff *skb, int offset, struct iovec *to,
size_t len, struct dma_pinned_list *pinned_list)
{
- int end = skb_headlen(skb);
- int i, copy = end - offset;
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
dma_cookie_t cookie = 0;
/* Copy header. */
@@ -69,9 +69,11 @@ int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
/* Copy paged appendix. Hmm... why does this look so complicated? */
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
- BUG_TRAP(len >= 0);
+ int end;
- end = offset + skb_shinfo(skb)->frags[i].size;
+ BUG_TRAP(start <= offset + len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
copy = end - offset;
if ((copy = end - offset) > 0) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
@@ -80,8 +82,8 @@ int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
if (copy > len)
copy = len;
- cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list,
- page, frag->page_offset, copy);
+ cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list, page,
+ frag->page_offset + offset - start, copy);
if (cookie < 0)
goto fault;
len -= copy;
@@ -89,21 +91,25 @@ int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
goto end;
offset += copy;
}
+ start = end;
}
if (skb_shinfo(skb)->frag_list) {
struct sk_buff *list = skb_shinfo(skb)->frag_list;
for (; list; list = list->next) {
- BUG_TRAP(len >= 0);
+ int end;
+
+ BUG_TRAP(start <= offset + len);
- end = offset + list->len;
+ end = start + list->len;
copy = end - offset;
if (copy > 0) {
if (copy > len)
copy = len;
cookie = dma_skb_copy_datagram_iovec(chan, list,
- 0, to, copy, pinned_list);
+ offset - start, to, copy,
+ pinned_list);
if (cookie < 0)
goto fault;
len -= copy;
@@ -111,6 +117,7 @@ int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
goto end;
offset += copy;
}
+ start = end;
}
}