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authorJean Delvare <jdelvare@suse.de>2007-04-26 00:44:22 -0700
committerDavid S. Miller <davem@davemloft.net>2007-04-26 00:44:22 -0700
commiteefa3906283a2b60a6d02a2cda593a7d7d7946c5 (patch)
treea4e1f3b8dca04b8dff3cd99dc43f771f798558fb /net/core/user_dma.c
parent28d8909bc790d936ce33f4402adf7577533bbd4b (diff)
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[NET]: Clean up sk_buff walkers.
I noticed recently that, in skb_checksum(), "offset" and "start" are essentially the same thing and have the same value throughout the function, despite being computed differently. Using a single variable allows some cleanups and makes the skb_checksum() function smaller, more readable, and presumably marginally faster. We appear to have many other "sk_buff walker" functions built on the exact same model, so the cleanup applies to them, too. Here is a list of the functions I found to be affected: net/appletalk/ddp.c:atalk_sum_skb() net/core/datagram.c:skb_copy_datagram_iovec() net/core/datagram.c:skb_copy_and_csum_datagram() net/core/skbuff.c:skb_copy_bits() net/core/skbuff.c:skb_store_bits() net/core/skbuff.c:skb_checksum() net/core/skbuff.c:skb_copy_and_csum_bit() net/core/user_dma.c:dma_skb_copy_datagram_iovec() net/xfrm/xfrm_algo.c:skb_icv_walk() net/xfrm/xfrm_algo.c:skb_to_sgvec() OTOH, I admit I'm a bit surprised, the cleanup is rather obvious so I'm really wondering if I am missing something. Can anyone please comment on this? Signed-off-by: Jean Delvare <jdelvare@suse.de> 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, 9 insertions, 16 deletions
diff --git a/net/core/user_dma.c b/net/core/user_dma.c
index 0ad1cd57bc39..89241cdeea3f 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 start = skb_headlen(skb);
- int i, copy = start - offset;
+ int end = skb_headlen(skb);
+ int i, copy = end - offset;
dma_cookie_t cookie = 0;
/* Copy header. */
@@ -69,11 +69,9 @@ 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++) {
- int end;
+ BUG_TRAP(len >= 0);
- BUG_TRAP(start <= offset + len);
-
- end = start + skb_shinfo(skb)->frags[i].size;
+ end = offset + skb_shinfo(skb)->frags[i].size;
copy = end - offset;
if ((copy = end - offset) > 0) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
@@ -82,8 +80,8 @@ 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 + offset - start, copy);
+ cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list,
+ page, frag->page_offset, copy);
if (cookie < 0)
goto fault;
len -= copy;
@@ -91,25 +89,21 @@ 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) {
- int end;
-
- BUG_TRAP(start <= offset + len);
+ BUG_TRAP(len >= 0);
- end = start + list->len;
+ end = offset + list->len;
copy = end - offset;
if (copy > 0) {
if (copy > len)
copy = len;
cookie = dma_skb_copy_datagram_iovec(chan, list,
- offset - start, to, copy,
- pinned_list);
+ 0, to, copy, pinned_list);
if (cookie < 0)
goto fault;
len -= copy;
@@ -117,7 +111,6 @@ int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
goto end;
offset += copy;
}
- start = end;
}
}