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[v2,net-next,1/8] net: cdc_ncm: reduce skb truesize in rx path

Message ID 1401435070-26721-2-git-send-email-bjorn@mork.no
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Bjørn Mork May 30, 2014, 7:31 a.m. UTC 
Cloning the big skbs we use for USB buffering chokes up TCP and
SCTP because the socket memory limits are hitting earlier than
they should. It is better to unconditionally copy the unwrapped
packets to freshly allocated skbs.

Reported-by: Jim Baxter <jim_baxter@mentor.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
---
 drivers/net/usb/cdc_ncm.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
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Patch

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 93c9ca9924eb..2bbbd65591c7 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -1289,12 +1289,11 @@  next_ndp:
 			break;
 
 		} else {
-			skb = skb_clone(skb_in, GFP_ATOMIC);
+			/* create a fresh copy to reduce truesize */
+			skb = netdev_alloc_skb_ip_align(dev->net,  len);
 			if (!skb)
 				goto error;
-			skb->len = len;
-			skb->data = ((u8 *)skb_in->data) + offset;
-			skb_set_tail_pointer(skb, len);
+			memcpy(skb_put(skb, len), skb_in->data + offset, len);
 			usbnet_skb_return(dev, skb);
 			payload += len;	/* count payload bytes in this NTB */
 		}