kernel: use skb_cow_head() to deal with cloned skbs

[openwrt/staging/dedeckeh.git] / target / linux / generic / patches-4.4 / 030-1-smsc95xx-Use-skb_cow_head-to-deal-with-cloned-skbs.patch

diff --git a/target/linux/generic/patches-4.4/030-1-smsc95xx-Use-skb_cow_head-to-deal-with-cloned-skbs.patch b/target/linux/generic/patches-4.4/030-1-smsc95xx-Use-skb_cow_head-to-deal-with-cloned-skbs.patch
new file mode 100644 (file)
index 0000000..36fb936
--- /dev/null
+++ b/target/linux/generic/patches-4.4/030-1-smsc95xx-Use-skb_cow_head-to-deal-with-cloned-skbs.patch
@@ -0,0 +1,40 @@
+From e9156cd26a495a18706e796f02a81fee41ec14f4 Mon Sep 17 00:00:00 2001
+From: James Hughes <james.hughes@raspberrypi.org>
+Date: Wed, 19 Apr 2017 11:13:40 +0100
+Subject: [PATCH] smsc95xx: Use skb_cow_head to deal with cloned skbs
+
+The driver was failing to check that the SKB wasn't cloned
+before adding checksum data.
+Replace existing handling to extend/copy the header buffer
+with skb_cow_head.
+
+Signed-off-by: James Hughes <james.hughes@raspberrypi.org>
+Acked-by: Eric Dumazet <edumazet@google.com>
+Acked-by: Woojung Huh <Woojung.Huh@microchip.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/usb/smsc95xx.c | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+--- a/drivers/net/usb/smsc95xx.c
++++ b/drivers/net/usb/smsc95xx.c
+@@ -1835,13 +1835,13 @@ static struct sk_buff *smsc95xx_tx_fixup
+       /* We do not advertise SG, so skbs should be already linearized */
+       BUG_ON(skb_shinfo(skb)->nr_frags);
+ 
+-      if (skb_headroom(skb) < overhead) {
+-              struct sk_buff *skb2 = skb_copy_expand(skb,
+-                      overhead, 0, flags);
++      /* Make writable and expand header space by overhead if required */
++      if (skb_cow_head(skb, overhead)) {
++              /* Must deallocate here as returning NULL to indicate error
++               * means the skb won't be deallocated in the caller.
++               */
+               dev_kfree_skb_any(skb);
+-              skb = skb2;
+-              if (!skb)
+-                      return NULL;
++              return NULL;
+       }
+ 
+       if (csum) {