From fbb398a832086c370bce47789e155bf5a08774e9 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
Date: Tue, 9 Jun 2009 00:18:59 -0700
Subject: net/core/skbuff.c: Use frag list abstraction interfaces.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a2473b1..49961ba 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -210,7 +210,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	shinfo->gso_type = 0;
 	shinfo->ip6_frag_id = 0;
 	shinfo->tx_flags.flags = 0;
-	shinfo->frag_list = NULL;
+	skb_frag_list_init(skb);
 	memset(&shinfo->hwtstamps, 0, sizeof(shinfo->hwtstamps));
 
 	if (fclone) {
@@ -323,7 +323,7 @@ static void skb_clone_fraglist(struct sk_buff *skb)
 {
 	struct sk_buff *list;
 
-	for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
+	skb_walk_frags(skb, list)
 		skb_get(list);
 }
 
@@ -338,7 +338,7 @@ static void skb_release_data(struct sk_buff *skb)
 				put_page(skb_shinfo(skb)->frags[i].page);
 		}
 
-		if (skb_shinfo(skb)->frag_list)
+		if (skb_has_frags(skb))
 			skb_drop_fraglist(skb);
 
 		kfree(skb->head);
@@ -503,7 +503,7 @@ int skb_recycle_check(struct sk_buff *skb, int skb_size)
 	shinfo->gso_type = 0;
 	shinfo->ip6_frag_id = 0;
 	shinfo->tx_flags.flags = 0;
-	shinfo->frag_list = NULL;
+	skb_frag_list_init(skb);
 	memset(&shinfo->hwtstamps, 0, sizeof(shinfo->hwtstamps));
 
 	memset(skb, 0, offsetof(struct sk_buff, tail));
@@ -758,7 +758,7 @@ struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
 		skb_shinfo(n)->nr_frags = i;
 	}
 
-	if (skb_shinfo(skb)->frag_list) {
+	if (skb_has_frags(skb)) {
 		skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
 		skb_clone_fraglist(n);
 	}
@@ -821,7 +821,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
 		get_page(skb_shinfo(skb)->frags[i].page);
 
-	if (skb_shinfo(skb)->frag_list)
+	if (skb_has_frags(skb))
 		skb_clone_fraglist(skb);
 
 	skb_release_data(skb);
@@ -1093,7 +1093,7 @@ drop_pages:
 		for (; i < nfrags; i++)
 			put_page(skb_shinfo(skb)->frags[i].page);
 
-		if (skb_shinfo(skb)->frag_list)
+		if (skb_has_frags(skb))
 			skb_drop_fraglist(skb);
 		goto done;
 	}
@@ -1188,7 +1188,7 @@ unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
 	/* Optimization: no fragments, no reasons to preestimate
 	 * size of pulled pages. Superb.
 	 */
-	if (!skb_shinfo(skb)->frag_list)
+	if (!skb_has_frags(skb))
 		goto pull_pages;
 
 	/* Estimate size of pulled pages. */
@@ -1285,8 +1285,9 @@ EXPORT_SYMBOL(__pskb_pull_tail);
 
 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
 {
-	int i, copy;
 	int start = skb_headlen(skb);
+	struct sk_buff *frag_iter;
+	int i, copy;
 
 	if (offset > (int)skb->len - len)
 		goto fault;
@@ -1328,28 +1329,23 @@ int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
 		start = end;
 	}
 
-	if (skb_shinfo(skb)->frag_list) {
-		struct sk_buff *list = skb_shinfo(skb)->frag_list;
+	skb_walk_frags(skb, frag_iter) {
+		int end;
 
-		for (; list; list = list->next) {
-			int end;
-
-			WARN_ON(start > offset + len);
-
-			end = start + list->len;
-			if ((copy = end - offset) > 0) {
-				if (copy > len)
-					copy = len;
-				if (skb_copy_bits(list, offset - start,
-						  to, copy))
-					goto fault;
-				if ((len -= copy) == 0)
-					return 0;
-				offset += copy;
-				to     += copy;
-			}
-			start = end;
+		WARN_ON(start > offset + len);
+
+		end = start + frag_iter->len;
+		if ((copy = end - offset) > 0) {
+			if (copy > len)
+				copy = len;
+			if (skb_copy_bits(frag_iter, offset - start, to, copy))
+				goto fault;
+			if ((len -= copy) == 0)
+				return 0;
+			offset += copy;
+			to     += copy;
 		}
+		start = end;
 	}
 	if (!len)
 		return 0;
@@ -1534,6 +1530,7 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
 		.ops = &sock_pipe_buf_ops,
 		.spd_release = sock_spd_release,
 	};
+	struct sk_buff *frag_iter;
 	struct sock *sk = skb->sk;
 
 	/*
@@ -1548,13 +1545,11 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
 	/*
 	 * now see if we have a frag_list to map
 	 */
-	if (skb_shinfo(skb)->frag_list) {
-		struct sk_buff *list = skb_shinfo(skb)->frag_list;
-
-		for (; list && tlen; list = list->next) {
-			if (__skb_splice_bits(list, &offset, &tlen, &spd, sk))
-				break;
-		}
+	skb_walk_frags(skb, frag_iter) {
+		if (!tlen)
+			break;
+		if (__skb_splice_bits(frag_iter, &offset, &tlen, &spd, sk))
+			break;
 	}
 
 done:
@@ -1593,8 +1588,9 @@ done:
 
 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
 {
-	int i, copy;
 	int start = skb_headlen(skb);
+	struct sk_buff *frag_iter;
+	int i, copy;
 
 	if (offset > (int)skb->len - len)
 		goto fault;
@@ -1635,28 +1631,24 @@ int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
 		start = end;
 	}
 
-	if (skb_shinfo(skb)->frag_list) {
-		struct sk_buff *list = skb_shinfo(skb)->frag_list;
+	skb_walk_frags(skb, frag_iter) {
+		int end;
 
-		for (; list; list = list->next) {
-			int end;
-
-			WARN_ON(start > offset + len);
-
-			end = start + list->len;
-			if ((copy = end - offset) > 0) {
-				if (copy > len)
-					copy = len;
-				if (skb_store_bits(list, offset - start,
-						   from, copy))
-					goto fault;
-				if ((len -= copy) == 0)
-					return 0;
-				offset += copy;
-				from += copy;
-			}
-			start = end;
+		WARN_ON(start > offset + len);
+
+		end = start + frag_iter->len;
+		if ((copy = end - offset) > 0) {
+			if (copy > len)
+				copy = len;
+			if (skb_store_bits(frag_iter, offset - start,
+					   from, copy))
+				goto fault;
+			if ((len -= copy) == 0)
+				return 0;
+			offset += copy;
+			from += copy;
 		}
+		start = end;
 	}
 	if (!len)
 		return 0;
@@ -1673,6 +1665,7 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset,
 {
 	int start = skb_headlen(skb);
 	int i, copy = start - offset;
+	struct sk_buff *frag_iter;
 	int pos = 0;
 
 	/* Checksum header. */
@@ -1712,29 +1705,25 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset,
 		start = end;
 	}
 
-	if (skb_shinfo(skb)->frag_list) {
-		struct sk_buff *list = skb_shinfo(skb)->frag_list;
+	skb_walk_frags(skb, frag_iter) {
+		int end;
 
-		for (; list; list = list->next) {
-			int end;
-
-			WARN_ON(start > offset + len);
-
-			end = start + list->len;
-			if ((copy = end - offset) > 0) {
-				__wsum csum2;
-				if (copy > len)
-					copy = len;
-				csum2 = skb_checksum(list, offset - start,
-						     copy, 0);
-				csum = csum_block_add(csum, csum2, pos);
-				if ((len -= copy) == 0)
-					return csum;
-				offset += copy;
-				pos    += copy;
-			}
-			start = end;
+		WARN_ON(start > offset + len);
+
+		end = start + frag_iter->len;
+		if ((copy = end - offset) > 0) {
+			__wsum csum2;
+			if (copy > len)
+				copy = len;
+			csum2 = skb_checksum(frag_iter, offset - start,
+					     copy, 0);
+			csum = csum_block_add(csum, csum2, pos);
+			if ((len -= copy) == 0)
+				return csum;
+			offset += copy;
+			pos    += copy;
 		}
+		start = end;
 	}
 	BUG_ON(len);
 
@@ -1749,6 +1738,7 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
 {
 	int start = skb_headlen(skb);
 	int i, copy = start - offset;
+	struct sk_buff *frag_iter;
 	int pos = 0;
 
 	/* Copy header. */
@@ -1793,31 +1783,27 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
 		start = end;
 	}
 
-	if (skb_shinfo(skb)->frag_list) {
-		struct sk_buff *list = skb_shinfo(skb)->frag_list;
+	skb_walk_frags(skb, frag_iter) {
+		__wsum csum2;
+		int end;
 
-		for (; list; list = list->next) {
-			__wsum csum2;
-			int end;
-
-			WARN_ON(start > offset + len);
-
-			end = start + list->len;
-			if ((copy = end - offset) > 0) {
-				if (copy > len)
-					copy = len;
-				csum2 = skb_copy_and_csum_bits(list,
-							       offset - start,
-							       to, copy, 0);
-				csum = csum_block_add(csum, csum2, pos);
-				if ((len -= copy) == 0)
-					return csum;
-				offset += copy;
-				to     += copy;
-				pos    += copy;
-			}
-			start = end;
+		WARN_ON(start > offset + len);
+
+		end = start + frag_iter->len;
+		if ((copy = end - offset) > 0) {
+			if (copy > len)
+				copy = len;
+			csum2 = skb_copy_and_csum_bits(frag_iter,
+						       offset - start,
+						       to, copy, 0);
+			csum = csum_block_add(csum, csum2, pos);
+			if ((len -= copy) == 0)
+				return csum;
+			offset += copy;
+			to     += copy;
+			pos    += copy;
 		}
+		start = end;
 	}
 	BUG_ON(len);
 	return csum;
@@ -2327,8 +2313,7 @@ next_skb:
 		st->frag_data = NULL;
 	}
 
-	if (st->root_skb == st->cur_skb &&
-	    skb_shinfo(st->root_skb)->frag_list) {
+	if (st->root_skb == st->cur_skb && skb_has_frags(st->root_skb)) {
 		st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
 		st->frag_idx = 0;
 		goto next_skb;
@@ -2639,7 +2624,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features)
 			} else
 				skb_get(fskb2);
 
-			BUG_ON(skb_shinfo(nskb)->frag_list);
+			SKB_FRAG_ASSERT(nskb);
 			skb_shinfo(nskb)->frag_list = fskb2;
 		}
 
@@ -2796,6 +2781,7 @@ __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
 {
 	int start = skb_headlen(skb);
 	int i, copy = start - offset;
+	struct sk_buff *frag_iter;
 	int elt = 0;
 
 	if (copy > 0) {
@@ -2829,26 +2815,22 @@ __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
 		start = end;
 	}
 
-	if (skb_shinfo(skb)->frag_list) {
-		struct sk_buff *list = skb_shinfo(skb)->frag_list;
-
-		for (; list; list = list->next) {
-			int end;
+	skb_walk_frags(skb, frag_iter) {
+		int end;
 
-			WARN_ON(start > offset + len);
+		WARN_ON(start > offset + len);
 
-			end = start + list->len;
-			if ((copy = end - offset) > 0) {
-				if (copy > len)
-					copy = len;
-				elt += __skb_to_sgvec(list, sg+elt, offset - start,
-						      copy);
-				if ((len -= copy) == 0)
-					return elt;
-				offset += copy;
-			}
-			start = end;
+		end = start + frag_iter->len;
+		if ((copy = end - offset) > 0) {
+			if (copy > len)
+				copy = len;
+			elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
+					      copy);
+			if ((len -= copy) == 0)
+				return elt;
+			offset += copy;
 		}
+		start = end;
 	}
 	BUG_ON(len);
 	return elt;
@@ -2896,7 +2878,7 @@ int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
 		return -ENOMEM;
 
 	/* Easy case. Most of packets will go this way. */
-	if (!skb_shinfo(skb)->frag_list) {
+	if (!skb_has_frags(skb)) {
 		/* A little of trouble, not enough of space for trailer.
 		 * This should not happen, when stack is tuned to generate
 		 * good frames. OK, on miss we reallocate and reserve even more
@@ -2931,7 +2913,7 @@ int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
 
 		if (skb1->next == NULL && tailbits) {
 			if (skb_shinfo(skb1)->nr_frags ||
-			    skb_shinfo(skb1)->frag_list ||
+			    skb_has_frags(skb1) ||
 			    skb_tailroom(skb1) < tailbits)
 				ntail = tailbits + 128;
 		}
@@ -2940,7 +2922,7 @@ int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
 		    skb_cloned(skb1) ||
 		    ntail ||
 		    skb_shinfo(skb1)->nr_frags ||
-		    skb_shinfo(skb1)->frag_list) {
+		    skb_has_frags(skb1)) {
 			struct sk_buff *skb2;
 
 			/* Fuck, we are miserable poor guys... */
-- 
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