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From: Sven Eckelmann <sven.eckelmann@gmx.de>
To: greg@kroah.com
Cc: b.a.t.m.a.n@lists.open-mesh.net
Subject: [B.A.T.M.A.N.] [PATCH 15/21] Staging: batman-adv: Create copy of skb with pre-allocated headroom
Date: Sun,  5 Sep 2010 01:58:32 +0200	[thread overview]
Message-ID: <1283644718-653-16-git-send-email-sven.eckelmann@gmx.de> (raw)
In-Reply-To: <1283644718-653-1-git-send-email-sven.eckelmann@gmx.de>

We can use skb_cow instead of a handwritten function to test and create
a writable skb buffer. This also allows us to pre-allocate headroom to
be able to send the data without re-allocating the buffer again to add
the ethernet header.

Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
---
 drivers/staging/batman-adv/routing.c |   77 ++++++++++-----------------------
 1 files changed, 24 insertions(+), 53 deletions(-)

diff --git a/drivers/staging/batman-adv/routing.c b/drivers/staging/batman-adv/routing.c
index d8e77ac..7e993a2 100644
--- a/drivers/staging/batman-adv/routing.c
+++ b/drivers/staging/batman-adv/routing.c
@@ -742,7 +742,6 @@ int recv_bat_packet(struct sk_buff *skb,
 {
 	struct ethhdr *ethhdr;
 	unsigned long flags;
-	struct sk_buff *skb_old;
 
 	/* drop packet if it has not necessary minimum size */
 	if (skb_headlen(skb) < sizeof(struct batman_packet))
@@ -758,18 +757,11 @@ int recv_bat_packet(struct sk_buff *skb,
 	if (is_bcast(ethhdr->h_source))
 		return NET_RX_DROP;
 
-	/* TODO: we use headlen instead of "length", because
-	 * only this data is paged in. */
-
 	/* create a copy of the skb, if needed, to modify it. */
-	if (!skb_clone_writable(skb, skb_headlen(skb))) {
-		skb_old = skb;
-		skb = skb_copy(skb, GFP_ATOMIC);
-		if (!skb)
-			return NET_RX_DROP;
-		ethhdr = (struct ethhdr *)skb_mac_header(skb);
-		kfree_skb(skb_old);
-	}
+	if (skb_cow(skb, 0) < 0)
+		return NET_RX_DROP;
+
+	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	spin_lock_irqsave(&orig_hash_lock, flags);
 	receive_aggr_bat_packet(ethhdr,
@@ -789,7 +781,6 @@ static int recv_my_icmp_packet(struct sk_buff *skb, size_t icmp_len)
 	struct orig_node *orig_node;
 	struct icmp_packet_rr *icmp_packet;
 	struct ethhdr *ethhdr;
-	struct sk_buff *skb_old;
 	struct batman_if *batman_if;
 	int ret;
 	unsigned long flags;
@@ -824,16 +815,11 @@ static int recv_my_icmp_packet(struct sk_buff *skb, size_t icmp_len)
 		spin_unlock_irqrestore(&orig_hash_lock, flags);
 
 		/* create a copy of the skb, if needed, to modify it. */
-		skb_old = NULL;
-		if (!skb_clone_writable(skb, icmp_len)) {
-			skb_old = skb;
-			skb = skb_copy(skb, GFP_ATOMIC);
-			if (!skb)
-				return NET_RX_DROP;
-			icmp_packet = (struct icmp_packet_rr *)skb->data;
-			ethhdr = (struct ethhdr *)skb_mac_header(skb);
-			kfree_skb(skb_old);
-		}
+		if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
+			return NET_RX_DROP;
+
+		icmp_packet = (struct icmp_packet_rr *)skb->data;
+		ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 		memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 		memcpy(icmp_packet->orig,
@@ -857,7 +843,6 @@ static int recv_icmp_ttl_exceeded(struct sk_buff *skb, size_t icmp_len)
 	struct orig_node *orig_node;
 	struct icmp_packet *icmp_packet;
 	struct ethhdr *ethhdr;
-	struct sk_buff *skb_old;
 	struct batman_if *batman_if;
 	int ret;
 	unsigned long flags;
@@ -893,15 +878,11 @@ static int recv_icmp_ttl_exceeded(struct sk_buff *skb, size_t icmp_len)
 		spin_unlock_irqrestore(&orig_hash_lock, flags);
 
 		/* create a copy of the skb, if needed, to modify it. */
-		if (!skb_clone_writable(skb, icmp_len)) {
-			skb_old = skb;
-			skb = skb_copy(skb, GFP_ATOMIC);
-			if (!skb)
-				return NET_RX_DROP;
-			icmp_packet = (struct icmp_packet *) skb->data;
-			ethhdr = (struct ethhdr *)skb_mac_header(skb);
-			kfree_skb(skb_old);
-		}
+		if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
+			return NET_RX_DROP;
+
+		icmp_packet = (struct icmp_packet *) skb->data;
+		ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 		memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 		memcpy(icmp_packet->orig,
@@ -924,7 +905,6 @@ int recv_icmp_packet(struct sk_buff *skb)
 	struct icmp_packet_rr *icmp_packet;
 	struct ethhdr *ethhdr;
 	struct orig_node *orig_node;
-	struct sk_buff *skb_old;
 	struct batman_if *batman_if;
 	int hdr_size = sizeof(struct icmp_packet);
 	int ret;
@@ -990,15 +970,11 @@ int recv_icmp_packet(struct sk_buff *skb)
 		spin_unlock_irqrestore(&orig_hash_lock, flags);
 
 		/* create a copy of the skb, if needed, to modify it. */
-		if (!skb_clone_writable(skb, hdr_size)) {
-			skb_old = skb;
-			skb = skb_copy(skb, GFP_ATOMIC);
-			if (!skb)
-				return NET_RX_DROP;
-			icmp_packet = (struct icmp_packet_rr *)skb->data;
-			ethhdr = (struct ethhdr *)skb_mac_header(skb);
-			kfree_skb(skb_old);
-		}
+		if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
+			return NET_RX_DROP;
+
+		icmp_packet = (struct icmp_packet_rr *)skb->data;
+		ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 		/* decrement ttl */
 		icmp_packet->ttl--;
@@ -1137,7 +1113,6 @@ static int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,
 	struct orig_node *orig_node;
 	struct neigh_node *router;
 	struct batman_if *batman_if;
-	struct sk_buff *skb_old;
 	uint8_t dstaddr[ETH_ALEN];
 	unsigned long flags;
 	struct unicast_packet *unicast_packet =
@@ -1173,15 +1148,11 @@ static int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,
 	spin_unlock_irqrestore(&orig_hash_lock, flags);
 
 	/* create a copy of the skb, if needed, to modify it. */
-	if (!skb_clone_writable(skb, hdr_size)) {
-		skb_old = skb;
-		skb = skb_copy(skb, GFP_ATOMIC);
-		if (!skb)
-			return NET_RX_DROP;
-		unicast_packet = (struct unicast_packet *) skb->data;
-		ethhdr = (struct ethhdr *)skb_mac_header(skb);
-		kfree_skb(skb_old);
-	}
+	if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
+		return NET_RX_DROP;
+
+	unicast_packet = (struct unicast_packet *) skb->data;
+	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	/* decrement ttl */
 	unicast_packet->ttl--;
-- 
1.7.1


  parent reply	other threads:[~2010-09-04 23:58 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-04 23:58 [B.A.T.M.A.N.] Staging: batman-adv for 2.6.37 (1) Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 01/21] Revert: "Staging: batman-adv: Adding netfilter-bridge hooks" Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 02/21] Staging: batman-adv: Remove CHANGELOG Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 03/21] Staging: batman-adv: Start new development cycle Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 04/21] Staging: batman-adv: Count Ethernet header for incoming packets Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 05/21] Staging: batman-adv: Calculate hamming weight using optimized kernel functions Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 06/21] Staging: batman-adv: move queue counters into bat_priv Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 07/21] Staging: batman-adv: refactoring unicast payload code Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 08/21] Staging: batman-adv: layer2 unicast packet fragmentation Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 09/21] Staging: batman-adv: Directly prepare icmp packets in socket buffer Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 10/21] Staging: batman-adv: register the batman-adv packet type per interface Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 11/21] Staging: batman-adv: Keep header writable and unshared Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 12/21] Staging: batman-adv: Only clone skb data for multiple broadcasts Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 13/21] Staging: batman-adv: Aggregate batman packets directly in skb Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 14/21] Staging: batman-adv: Prepare vis packets directly inside a skb Sven Eckelmann
2010-09-04 23:58 ` Sven Eckelmann [this message]
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 16/21] Staging: batman-adv: Provide full headers and packets as linear skb Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 17/21] Staging: batman-adv: attach each hard-interface to a soft-interface Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 18/21] Staging: batman-adv: multiple mesh clouds Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 19/21] Staging: batman-adv: Remove duplicate of attached device name Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 20/21] Staging: batman-adv: Don't inform about dropped packets in nodebug Sven Eckelmann
2010-09-04 23:58 ` [B.A.T.M.A.N.] [PATCH 21/21] Staging: batman-adv: Update mtu of bat device by changing mtu of slave device Sven Eckelmann
2010-09-05  7:33 ` [B.A.T.M.A.N.] Staging: batman-adv for 2.6.37 (1) Greg KH

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