From: Jim Baxter Date: Mon, 7 Jul 2014 17:33:19 +0000 (+0100) Subject: usb: gadget: NCM: Stop RX TCP Bursts getting dropped. X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=66847062a6e33fa54b98714c7c954353e2596645;p=linux-beck.git 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 --- 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);