On 24-4-2017 15:03, James Hughes wrote:
> 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.
>
> This patch depends on
> brcmfmac: Ensure pointer correctly set if skb data location changes
Hi James,
I actually thought I was going to tackle this so I spend some time
working on it today, but I will submit that as a subsequent patch. Below
some comments but apart from that:
Acked-by: Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx>
> Signed-off-by: James Hughes <james.hughes@xxxxxxxxxxxxxxx>
> ---
> Changes in v2
> Makes the _cow_ call at the entry point of the skb in to the
> stack, means only needs to be done once, and error handling
> is easier.
> Split a separate minor bug fix off to a separate patch (which
> this patch depends on)
>
>
>
> .../net/wireless/broadcom/brcm80211/brcmfmac/core.c | 19 ++++---------------
> 1 file changed, 4 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> index 9b7c19a508ac..88f8675a94c2 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> @@ -211,22 +211,11 @@ 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",
> - brcmf_ifname(ifp));
> - drvr->bus_if->tx_realloc++;
> - skb2 = skb_realloc_headroom(skb, drvr->hdrlen);
> + /* Make sure there's enough room for any header, and make it writable */
Please rephrase: /* Make sure there is enough writable headroom */
Just do:
ret = skb_cow_head(skb, drvr->hdrlen);
if (ret < 0) {
brcmf_err("%s: skb_cow_head failed\n",
brcmf_ifname(ifp));
> + if (skb_cow_head(skb, drvr->hdrlen)) {
> dev_kfree_skb(skb);
> - skb = skb2;
> - if (skb == NULL) {
> - brcmf_err("%s: skb_realloc_headroom failed\n",
> - brcmf_ifname(ifp));
> - ret = -ENOMEM;
> - goto done;
> - }
> + ret = -ENOMEM;
... and drop this assignment.
> + goto done;
> }
>
> /* validate length for ether packet */
>
