netdev - [v2 PATCH 2/4] tcp: Move code related to head frag in tcp_try

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 03 May 2012 00:19:04 -0700
From:	Alexander Duyck <alexander.h.duyck@...el.com>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, jeffrey.t.kirsher@...el.com,
	edumazet@...gle.com
Subject: [v2 PATCH 2/4] tcp: Move code related to head frag in tcp_try_coalesce

This change reorders the code related to the use of an skb->head_frag so it
is placed before we check the rest of the frags.  This allows the code to
read more linearly instead of like some sort of loop.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
Cc: Eric Dumazet <edumazet@...gle.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---

 net/ipv4/tcp_input.c |   42 +++++++++++++++++++++++++-----------------
 1 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3cb273a..41fa5df 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4562,9 +4562,31 @@ merge:
 	if (skb_has_frag_list(to) || skb_has_frag_list(from))
 		return false;
 
-	if (skb_headlen(from) == 0 &&
-	    (skb_shinfo(to)->nr_frags +
-	     skb_shinfo(from)->nr_frags <= MAX_SKB_FRAGS)) {
+	if (skb_headlen(from) != 0) {
+		struct page *page;
+		unsigned int offset;
+
+		if (skb_shinfo(to)->nr_frags +
+		    skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
+			return false;
+
+		if (!from->head_frag || skb_cloned(from))
+			return false;
+
+		delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
+
+		page = virt_to_head_page(from->head);
+		offset = from->data - (unsigned char *)page_address(page);
+
+		skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
+				   page, offset, skb_headlen(from));
+		*fragstolen = true;
+		goto copyfrags;
+	} else {
+		if (skb_shinfo(to)->nr_frags +
+		    skb_shinfo(from)->nr_frags > MAX_SKB_FRAGS)
+			return false;
+
 		delta = from->truesize -
 			SKB_TRUESIZE(skb_end_pointer(from) - from->head);
 copyfrags:
@@ -4587,20 +4609,6 @@ copyfrags:
 		to->data_len += len;
 		goto merge;
 	}
-	if (from->head_frag && !skb_cloned(from)) {
-		struct page *page;
-		unsigned int offset;
-
-		if (skb_shinfo(to)->nr_frags + skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
-			return false;
-		page = virt_to_head_page(from->head);
-		offset = from->data - (unsigned char *)page_address(page);
-		skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
-				   page, offset, skb_headlen(from));
-		*fragstolen = true;
-		delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
-		goto copyfrags;
-	}
 	return false;
 }
 

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html