netdev - Re: [PATCH net-next] r8169: remove not needed check in rtl_fw_write

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Message-ID: <20231123145407.GK6339@kernel.org>
Date: Thu, 23 Nov 2023 14:54:07 +0000
From: Simon Horman <horms@...nel.org>
To: Heiner Kallweit <hkallweit1@...il.com>
Cc: Realtek linux nic maintainers <nic_swsd@...ltek.com>,
	Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>,
	David Miller <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] r8169: remove not needed check in
 rtl_fw_write_firmware

On Thu, Nov 23, 2023 at 10:53:26AM +0100, Heiner Kallweit wrote:
> This check can never be true for a firmware file with a correct format.
> Existing checks in rtl_fw_data_ok() are sufficient, no problems with
> invalid firmware files are known.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
> ---
>  drivers/net/ethernet/realtek/r8169_firmware.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/realtek/r8169_firmware.c b/drivers/net/ethernet/realtek/r8169_firmware.c
> index cbc6b846d..ed6e721b1 100644
> --- a/drivers/net/ethernet/realtek/r8169_firmware.c
> +++ b/drivers/net/ethernet/realtek/r8169_firmware.c
> @@ -151,9 +151,6 @@ void rtl_fw_write_firmware(struct rtl8169_private *tp, struct rtl_fw *rtl_fw)
>  		u32 regno = (action & 0x0fff0000) >> 16;
>  		enum rtl_fw_opcode opcode = action >> 28;
>  
> -		if (!action)
> -			break;
> -

Hi Heiner,

I could well be wrong, but this does seem to guard against the following case:

1. data = 0
2. regno = 0
3. opcode = 0 (PHY_READ)

Which does not seem to be checked in rtl_fw_data_ok().

It's unclear to me if there is any value in this guard.

>  		switch (opcode) {
>  		case PHY_READ:
>  			predata = fw_read(tp, regno);
> -- 
> 2.43.0
>