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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/appletalk/ddp.c
parent28d8909bc790d936ce33f4402adf7577533bbd4b (diff)
[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/appletalk/ddp.c')
-rw-r--r--net/appletalk/ddp.c25
1 files changed, 9 insertions, 16 deletions
diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index f6a92a0b7aa6..16eda21fb38c 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -937,11 +937,11 @@ static unsigned long atalk_sum_partial(const unsigned char *data,
static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
int len, unsigned long sum)
{
- int start = skb_headlen(skb);
+ int end = skb_headlen(skb);
int i, copy;
/* checksum stuff in header space */
- if ( (copy = start - offset) > 0) {
+ if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
sum = atalk_sum_partial(skb->data + offset, copy, sum);
@@ -953,11 +953,9 @@ static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
/* checksum stuff in frags */
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;
if ((copy = end - offset) > 0) {
u8 *vaddr;
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
@@ -965,36 +963,31 @@ static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
if (copy > len)
copy = len;
vaddr = kmap_skb_frag(frag);
- sum = atalk_sum_partial(vaddr + frag->page_offset +
- offset - start, copy, sum);
+ sum = atalk_sum_partial(vaddr + frag->page_offset,
+ copy, sum);
kunmap_skb_frag(vaddr);
if (!(len -= copy))
return sum;
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;
if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
- sum = atalk_sum_skb(list, offset - start,
- copy, sum);
+ sum = atalk_sum_skb(list, 0, copy, sum);
if ((len -= copy) == 0)
return sum;
offset += copy;
}
- start = end;
}
}