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Date:   Tue, 13 Sep 2022 16:14:27 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Nathan Huckleberry <nhuck@google.com>
Cc:     Dan Carpenter <error27@gmail.com>, llvm@lists.linux.dev,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging: rtl8723bs: Fix rtw_xmit_entry return type
Message-ID: <YyEO01+suq0Wl/2F@dev-arch.thelio-3990X>
References: <20220912214617.929240-1-nhuck@google.com>
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On Mon, Sep 12, 2022 at 02:46:14PM -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/rtl8723bs/include/xmit_osdep.h should
be updated as well. With that:

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

> ---
>  drivers/staging/rtl8723bs/os_dep/xmit_linux.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/staging/rtl8723bs/os_dep/xmit_linux.c b/drivers/staging/rtl8723bs/os_dep/xmit_linux.c
> index 530e7a6c67c5..472d3ac0179b 100644
> --- a/drivers/staging/rtl8723bs/os_dep/xmit_linux.c
> +++ b/drivers/staging/rtl8723bs/os_dep/xmit_linux.c
> @@ -181,7 +181,7 @@ 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 = rtw_netdev_priv(pnetdev);
>  	struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
> @@ -217,15 +217,12 @@ int _rtw_xmit_entry(struct sk_buff *pkt, struct net_device *pnetdev)
>  	dev_kfree_skb_any(pkt);
>  
>  exit:
> -	return 0;
> +	return NETDEV_TX_OK;
>  }
>  
> -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)
>  {
> -	int ret = 0;
> -
>  	if (pkt)
> -		ret = _rtw_xmit_entry(pkt, pnetdev);
> -
> -	return ret;
> +		return _rtw_xmit_entry(pkt, pnetdev);
> +	return NETDEV_TX_OK;
>  }
> -- 
> 2.37.2.789.g6183377224-goog
>