From 66847062a6e33fa54b98714c7c954353e2596645 Mon Sep 17 00:00:00 2001 From: Jim Baxter Date: Mon, 7 Jul 2014 18:33:19 +0100 Subject: [PATCH] usb: gadget: NCM: Stop RX TCP Bursts getting dropped. This fixes a problem with dropped packets over 16k CDC-NCM when the connection is being heavily used. The issue was that the extracted frames cloned from the received frame were consuming more memory than necessary resulting in the truesize being ~32KB instead of ~2KB, this meant there was a high chance of reaching the sk_rcvbuf limit. Signed-off-by: Jim Baxter Acked-by: Eric Dumazet Signed-off-by: Felipe Balbi --- drivers/usb/gadget/f_ncm.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/usb/gadget/f_ncm.c b/drivers/usb/gadget/f_ncm.c index 5452fb663762..bcdc882cd415 100644 --- a/drivers/usb/gadget/f_ncm.c +++ b/drivers/usb/gadget/f_ncm.c @@ -1229,16 +1229,17 @@ static int ncm_unwrap_ntb(struct gether *port, index2 = get_ncm(&tmp, opts->dgram_item_len); dg_len2 = get_ncm(&tmp, opts->dgram_item_len); - skb2 = skb_clone(skb, GFP_ATOMIC); + /* + * Copy the data into a new skb. + * This ensures the truesize is correct + */ + skb2 = netdev_alloc_skb_ip_align(ncm->netdev, + dg_len - crc_len); if (skb2 == NULL) goto err; + memcpy(skb_put(skb2, dg_len - crc_len), + skb->data + index, dg_len - crc_len); - if (!skb_pull(skb2, index)) { - ret = -EOVERFLOW; - goto err; - } - - skb_trim(skb2, dg_len - crc_len); skb_queue_tail(list, skb2); ndp_len -= 2 * (opts->dgram_item_len * 2); -- 2.20.1