[PATCH v2 net-next 1/8] net: cdc_ncm: reduce skb truesize in rx path
From: Bjørn Mork <bjorn@mork.no>
Date: 2014-05-30 07:33:21
Subsystem:
networking drivers, the rest, usb cdc ethernet driver, usb networking drivers · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Oliver Neukum
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 <redacted> 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(-)
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 */ }
--
2.0.0.rc4