[RFC] net: cdc_ncm: reduce skb truesize in rx path
From: =3D?UTF-8?q?Bj=3DC3=3DB8rn=3D20Mork?=3D
Date: Fri May 23 2014 - 03:40:51 EST
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@xxxxxxxxxx>
Signed-off-by: Bj=C3=B8rn Mork <bjorn@xxxxxxx>
---
drivers/net/usb/cdc_ncm.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
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;
=20
} else {
- skb =3D skb_clone(skb_in, GFP_ATOMIC);
+ /* create a fresh copy to reduce truesize */
+ skb =3D netdev_alloc_skb_ip_align(dev->net, len);
if (!skb)
goto error;
- skb->len =3D len;
- skb->data =3D ((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 +=3D len; /* count payload bytes in this NTB */
}
--=20
2.0.0.rc4
--=-=-=--
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