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Date:   Tue, 13 Sep 2022 16:16:56 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Nathan Huckleberry <nhuck@google.com>
Cc:     namcaov@gmail.com, Larry.Finger@lwfinger.net, error27@gmail.com,
        gregkh@linuxfoundation.org, insafonov@gmail.com,
        linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev,
        llvm@lists.linux.dev, makvihas@gmail.com, ndesaulniers@google.com,
        paskripkin@gmail.com, phil@philpotter.co.uk,
        saurav.girepunje@gmail.com, trix@redhat.com
Subject: Re: [PATCH v2] staging: r8188eu: Fix return type of rtw_xmit_entry
Message-ID: <YyEPaMVRmdGQdoql@dev-arch.thelio-3990X>
References: <CA+sZ8B8RStBhofQ0=vvzH5FeQ66fj90DdCj9EQSaVErbVPLi7g@mail.gmail.com>
 <20220913193322.18776-1-nhuck@google.com>
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On Tue, Sep 13, 2022 at 12:33:22PM -0700, Nathan Huckleberry wrote:
> The ndo_start_xmit field in net_device_ops is expected to be of type
> netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb, struct net_device *dev).
> 
> The mismatched return type breaks forward edge kCFI since the underlying
> function definition does not match the function hook definition.
> 
> The return type of rtw_xmit_entry should be changed from int to
> netdev_tx_t.
> 
> Reported-by: Dan Carpenter <error27@gmail.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Cc: llvm@lists.linux.dev
> Signed-off-by: Nathan Huckleberry <nhuck@google.com>

The prototype in drivers/staging/r8188eu/include/xmit_osdep.h should be
updated as well. With that:

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> Changes v1 -> v2:
>  - Rebased onto linux-next/master
> 
> ---
>  drivers/staging/r8188eu/core/rtw_xmit.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
> index 98864fc55b25..ea13f11b231b 100644
> --- a/drivers/staging/r8188eu/core/rtw_xmit.c
> +++ b/drivers/staging/r8188eu/core/rtw_xmit.c
> @@ -2289,7 +2289,7 @@ static int rtw_mlcst2unicst(struct adapter *padapter, struct sk_buff *skb)
>  	return true;
>  }
>  
> -int rtw_xmit_entry(struct sk_buff *pkt, struct net_device *pnetdev)
> +netdev_tx_t rtw_xmit_entry(struct sk_buff *pkt, struct net_device *pnetdev)
>  {
>  	struct adapter *padapter = (struct adapter *)rtw_netdev_priv(pnetdev);
>  	struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
> @@ -2323,5 +2323,5 @@ int rtw_xmit_entry(struct sk_buff *pkt, struct net_device *pnetdev)
>  	dev_kfree_skb_any(pkt);
>  
>  exit:
> -	return 0;
> +	return NETDEV_TX_OK;
>  }
> -- 
> 2.37.2.789.g6183377224-goog
>