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: fix lro_gen_skb() alignment

PATCH Applied Andrew Gallatin 2 participants 2 messages Dec 4, 2007 – Dec 5, 2007

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Networking Network drivers
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Andrew Gallatin

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#0 lore raw

PATCH 1/1 : fix lro_gen_skb() alignment

Add a field to the lro_mgr struct so that drivers can specify how much padding is required to align layer 3 headers when a packet is copied into a freshly allocated skb by inet_lro.c:lro_gen_skb(). Without padding, skbs generated by LRO will cause alignment warnings on architectures which require strict alignment (seen on sparc64).

Myri10GE is updated to use this field.

Signed off by: Andrew Gallatin <[email protected]>

drivers/net/myri10ge/myri10ge.c +1 -0
index 0f306dd..8def865 100644
@@ -1979,6 +1979,7 @@ static int myri10ge_open(struct net_devi
 	lro_mgr->lro_arr = mgp->rx_done.lro_desc;
 	lro_mgr->get_frag_header = myri10ge_get_frag_header;
 	lro_mgr->max_aggr = myri10ge_lro_max_pkts;
+	lro_mgr->frag_align_pad = 2;
 	if (lro_mgr->max_aggr > MAX_SKB_FRAGS)
 		lro_mgr->max_aggr = MAX_SKB_FRAGS;
include/linux/inet_lro.h +3 -0
index 1246d46..80335b7 100644
@@ -91,6 +91,9 @@ #define LRO_F_EXTRACT_VLAN_ID 2  /* Set 
 	int max_desc; /* Max number of LRO descriptors  */
 	int max_aggr; /* Max number of LRO packets to be aggregated */
 
+	int frag_align_pad; /* Padding required to properly align layer 3
+			     * headers in generated skb when using frags */
+
 	struct net_lro_desc *lro_arr; /* Array of LRO descriptors */
 
 	/*
net/ipv4/inet_lro.c +2 -1
index ac3b1d3..9a96c27 100644
@@ -401,10 +401,11 @@ static struct sk_buff *lro_gen_skb(struc
 	int data_len = len;
 	int hdr_len = min(len, hlen);
 
-	skb = netdev_alloc_skb(lro_mgr->dev, hlen);
+	skb = netdev_alloc_skb(lro_mgr->dev, hlen + lro_mgr->frag_align_pad);
 	if (!skb)
 		return NULL;
 
+	skb_reserve(skb, lro_mgr->frag_align_pad);
 	skb->len = len;
 	skb->data_len = len - hdr_len;
 	skb->truesize += true_size;
maintainer Applied
#1 lore raw

From: Andrew Gallatin <[email protected]>
Date: Tue, 04 Dec 2007 14:55:06 -0500

Quoted 10 lines

Add a field to the lro_mgr struct so that drivers can specify how much padding is required to align layer 3 headers when a packet is copied into a freshly allocated skb by inet_lro.c:lro_gen_skb(). Without padding, skbs generated by LRO will cause alignment warnings on architectures which require strict alignment (seen on sparc64).

Myri10GE is updated to use this field.

Signed off by: Andrew Gallatin <[email protected]>

Applied, thanks Andrew.