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From: Kalle Valo <kvalo@kernel.org>
To: Dmitry Antipov <dmantipov@yandex.ru>
Cc: Stanislaw Gruszka <stf_xl@wp.pl>,  lvc-project@linuxtesting.org,
  linux-wireless@vger.kernel.org
Subject: Re: [PATCH] wifi: rt2x00: remove useless code in
 rt2x00queue_create_tx_descriptor()
References: <20231212173421.119136-1-dmantipov@yandex.ru>
Date: Tue, 12 Dec 2023 20:04:11 +0200
In-Reply-To: <20231212173421.119136-1-dmantipov@yandex.ru> (Dmitry Antipov's
	message of "Tue, 12 Dec 2023 20:34:18 +0300")
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Dmitry Antipov <dmantipov@yandex.ru> writes:

> In 'rt2x00queue_create_tx_descriptor()', there is no need to call
> 'ieee80211_get_rts_cts_rate()' while checking for RTS/CTS frame
> since this function returns NULL or pointer to internal bitrate
> table entry, and the return value is not actually used. This way,
> 'rate' becomes block-scoped later when determining the modulation.
> Compile tested only.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
> ---
>  drivers/net/wireless/ralink/rt2x00/rt2x00queue.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c b/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c
> index 98df0aef8168..7f9955deb204 100644
> --- a/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c
> +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c
> @@ -389,7 +389,6 @@ static void rt2x00queue_create_tx_descriptor(struct rt2x00_dev *rt2x00dev,
>  	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
>  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
>  	struct ieee80211_tx_rate *txrate = &tx_info->control.rates[0];
> -	struct ieee80211_rate *rate;

I think this should be kept.

> @@ -463,7 +459,8 @@ static void rt2x00queue_create_tx_descriptor(struct rt2x00_dev *rt2x00dev,
>  	else if (txrate->flags & IEEE80211_TX_RC_MCS)
>  		txdesc->rate_mode = RATE_MODE_HT_MIX;
>  	else {
> -		rate = ieee80211_get_tx_rate(rt2x00dev->hw, tx_info);
> +		struct ieee80211_rate *rate =
> +			ieee80211_get_tx_rate(rt2x00dev->hw, tx_info);

As I find it bad practice to declarare variables within if/else blocks.

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