lkml.org 
[lkml]   [2014]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v1 3/3] usb: gadget: NCM: Stop RX TCP Bursts getting dropped.
Date
This fixes a problem with dropped packets over 16k CDC-NCM
when the connection is being heavily used.

The issue was that the skb truesize for the unpacked NCM
packets was too high after they were cloned from the 16k
skb, this lead to the potential memory calculated by the
Kernel running out of memory earlier then it should.

Signed-off-by: Jim Baxter <jim_baxter@mentor.com>
---
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 5452fb6..bcdc882 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);
--
1.7.9.5


\
 
 \ /
  Last update: 2014-05-29 20:01    [W:0.116 / U:0.788 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site