brcmfmac: Make skb header writable before use

BugLink: http://bugs.launchpad.net/bugs/1691418
commit 9cc4b7cb86cbcc6330a3faa8cd65268cd2d3c227 upstream.

The driver was making changes to the skb_header without
ensuring it was writable (i.e. uncloned).
This patch also removes some boiler plate header size
checking/adjustment code as that is also handled by the
skb_cow_header function used to make header writable.

Signed-off-by: James Hughes <james.hughes@raspberrypi.org>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/core.c b/drivers/net/wireless/brcm80211/brcmfmac/core.c
index eb0e9fde6d541642294b80953dc6a5de0dfe9c37..82753e7c7e7ccc3495b79fbe454ced800e91d0fb 100644 (file)
--- a/drivers/net/wireless/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/core.c
@@ -232,22 +232,13 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
                goto done;
        }
 
-       /* Make sure there's enough room for any header */
-       if (skb_headroom(skb) < drvr->hdrlen) {
-               struct sk_buff *skb2;
-
-               brcmf_dbg(INFO, "%s: insufficient headroom\n",
+       /* Make sure there's enough writable headroom*/
+       ret = skb_cow_head(skb, drvr->hdrlen);
+       if (ret < 0) {
+               brcmf_err("%s: skb_cow_head failed\n",
                          brcmf_ifname(drvr, ifp->bssidx));
-               drvr->bus_if->tx_realloc++;
-               skb2 = skb_realloc_headroom(skb, drvr->hdrlen);
                dev_kfree_skb(skb);
-               skb = skb2;
-               if (skb == NULL) {
-                       brcmf_err("%s: skb_realloc_headroom failed\n",
-                                 brcmf_ifname(drvr, ifp->bssidx));
-                       ret = -ENOMEM;
-                       goto done;
-               }
+               goto done;
        }
 
        /* validate length for ether packet */