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Message-ID: <20191012115509.jrqe43yozs7kknv5@shells.gnugeneration.com>
Date: Sat, 12 Oct 2019 04:55:09 -0700
From: Vito Caputo <vcaputo@...garu.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] net: core: datagram: tidy up copy functions a bit
Eliminate some verbosity by using min() macro and consolidating some
things, also fix inconsistent zero tests (! vs. == 0).
Signed-off-by: Vito Caputo <vcaputo@...garu.com>
---
net/core/datagram.c | 44 ++++++++++++++------------------------------
1 file changed, 14 insertions(+), 30 deletions(-)
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 4cc8dc5db2b7..08d403f93952 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -413,13 +413,11 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
struct iov_iter *), void *data)
{
int start = skb_headlen(skb);
- int i, copy = start - offset, start_off = offset, n;
+ int i, copy, start_off = offset, n;
struct sk_buff *frag_iter;
/* Copy header. */
- if (copy > 0) {
- if (copy > len)
- copy = len;
+ if ((copy = min(start - offset, len)) > 0) {
n = cb(skb->data + offset, copy, data, to);
offset += n;
if (n != copy)
@@ -430,39 +428,33 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
/* Copy paged appendix. Hmm... why does this look so complicated? */
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
- int end;
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ int end = start + skb_frag_size(frag);
WARN_ON(start > offset + len);
- end = start + skb_frag_size(frag);
- if ((copy = end - offset) > 0) {
+ if ((copy = min(end - offset, len)) > 0) {
struct page *page = skb_frag_page(frag);
u8 *vaddr = kmap(page);
- if (copy > len)
- copy = len;
n = cb(vaddr + skb_frag_off(frag) + offset - start,
copy, data, to);
kunmap(page);
offset += n;
if (n != copy)
goto short_copy;
- if (!(len -= copy))
+ if ((len -= copy) == 0)
return 0;
}
start = end;
}
skb_walk_frags(skb, frag_iter) {
- int end;
+ int end = start + frag_iter->len;
WARN_ON(start > offset + len);
- end = start + frag_iter->len;
- if ((copy = end - offset) > 0) {
- if (copy > len)
- copy = len;
+ if ((copy = min(end - offset, len)) > 0) {
if (__skb_datagram_iter(frag_iter, offset - start,
to, copy, fault_short, cb, data))
goto fault;
@@ -545,13 +537,11 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
int len)
{
int start = skb_headlen(skb);
- int i, copy = start - offset;
struct sk_buff *frag_iter;
+ int i, copy;
/* Copy header. */
- if (copy > 0) {
- if (copy > len)
- copy = len;
+ if ((copy = min(start - offset, len)) > 0) {
if (copy_from_iter(skb->data + offset, copy, from) != copy)
goto fault;
if ((len -= copy) == 0)
@@ -561,24 +551,21 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
/* Copy paged appendix. Hmm... why does this look so complicated? */
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
- int end;
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ int end = start + skb_frag_size(frag);
WARN_ON(start > offset + len);
- end = start + skb_frag_size(frag);
- if ((copy = end - offset) > 0) {
+ if ((copy = min(end - offset, len)) > 0) {
size_t copied;
- if (copy > len)
- copy = len;
copied = copy_page_from_iter(skb_frag_page(frag),
skb_frag_off(frag) + offset - start,
copy, from);
if (copied != copy)
goto fault;
- if (!(len -= copy))
+ if ((len -= copy) == 0)
return 0;
offset += copy;
}
@@ -586,14 +573,11 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
}
skb_walk_frags(skb, frag_iter) {
- int end;
+ int end = start + frag_iter->len;
WARN_ON(start > offset + len);
- end = start + frag_iter->len;
- if ((copy = end - offset) > 0) {
- if (copy > len)
- copy = len;
+ if ((copy = min(end - offset, len)) > 0) {
if (skb_copy_datagram_from_iter(frag_iter,
offset - start,
from, copy))
--
2.11.0
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