net/core: Change loop conditions so min() can be used

Loops like:
	int copied = ...;
	...
	while (copied) {
		use = min_t(type, copied, PAGE_SIZE - offset);
		...
		copied -= 0;
	}
can be converted to a plain min() if the comparison is changed to:
	while (copied > 0) {
This removes any chance of high bits being discded by min_t().
(In the case above PAGE_SIZE is 64bits so the 'int' cast is safe,
but there are plenty of cases where the check shows up bugs.)

Signed-off-by: David Laight <[email protected]>

Author: David Laight

net/core/datagram.c

@@ -664,8 +664,8 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
 		head = compound_head(pages[n]);
 		order = compound_order(head);
 
-		for (refs = 0; copied != 0; start = 0) {
-			int size = min_t(int, copied, PAGE_SIZE - start);
+		for (refs = 0; copied > 0; start = 0) {
+			int size = min(copied, PAGE_SIZE - start);
 
 			if (pages[n] - head > (1UL << order) - 1) {
 				head = compound_head(pages[n]);
@@ -783,7 +783,7 @@ EXPORT_SYMBOL(__zerocopy_sg_from_iter);
  */
 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from)
 {
-	int copy = min_t(int, skb_headlen(skb), iov_iter_count(from));
+	int copy = min(skb_headlen(skb), iov_iter_count(from));
 
 	/* copy up to skb headlen */
 	if (skb_copy_datagram_from_iter(skb, 0, from, copy))

net/core/skmsg.c

@@ -335,8 +335,8 @@ int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 		bytes -= copied;
 		msg->sg.size += copied;
 
-		while (copied) {
-			use = min_t(int, copied, PAGE_SIZE - offset);
+		while (copied > 0) {
+			use = min(copied, PAGE_SIZE - offset);
 			sg_set_page(&msg->sg.data[msg->sg.end],
 				    pages[i], use, offset);
 			sg_unmark_end(&msg->sg.data[msg->sg.end]);