Thread (3 messages) flat view 3 messages, 3 authors, 2012-07-17
STALE5146d

[PATCH net-next] be2net: dont pull too much data in skb linear part

From: Eric Dumazet <hidden>
Date: 2012-07-13 13:19:46
Subsystem: emulex 10gbps nic be2, be3-r, lancer, skyhawk-r driver (be2net), networking drivers, the rest · Maintainers: Ajit Khaparde, Sriharsha Basavapatna, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

From: Eric Dumazet <edumazet@google.com>

skb_fill_rx_data() pulls 64 byte of data in skb->data

Its too much for TCP (with no options) on IPv4, as total size of headers
is 14 + 40 = 54

This means tcp stack and splice() are suboptimal, since tcp payload
is in part in tcp->data, and in part in skb frag.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 drivers/net/ethernet/emulex/benet/be_main.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index 7e989d0..f18375c 100644
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -1228,16 +1228,16 @@ static void skb_fill_rx_data(struct be_rx_obj *rxo, struct sk_buff *skb,
 	/* Copy data in the first descriptor of this completion */
 	curr_frag_len = min(rxcp->pkt_size, rx_frag_size);
 
-	/* Copy the header portion into skb_data */
-	hdr_len = min(BE_HDR_LEN, curr_frag_len);
-	memcpy(skb->data, start, hdr_len);
 	skb->len = curr_frag_len;
 	if (curr_frag_len <= BE_HDR_LEN) { /* tiny packet */
+		memcpy(skb->data, start, curr_frag_len);
 		/* Complete packet has now been moved to data */
 		put_page(page_info->page);
 		skb->data_len = 0;
 		skb->tail += curr_frag_len;
 	} else {
+		hdr_len = ETH_HLEN;
+		memcpy(skb->data, start, hdr_len);
 		skb_shinfo(skb)->nr_frags = 1;
 		skb_frag_set_page(skb, 0, page_info->page);
 		skb_shinfo(skb)->frags[0].page_offset =
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