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From: Kalle Valo <kvalo@kernel.org>
To: Qing Wang <wangqing@vivo.com>
Cc: Maya Erez <merez@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	linux-wireless@vger.kernel.org, wil6210@qti.qualcomm.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: wireless: ath: use div64_u64() instead of do_div()
Date: Thu, 10 Feb 2022 14:16:28 +0200	[thread overview]
Message-ID: <877da2c3xf.fsf@tynnyri.adurom.net> (raw)
In-Reply-To: <1644395972-4303-1-git-send-email-wangqing@vivo.com> (Qing Wang's message of "Wed, 9 Feb 2022 00:39:32 -0800")

Qing Wang <wangqing@vivo.com> writes:

> From: Wang Qing <wangqing@vivo.com>
>
> do_div() does a 64-by-32 division.
> When the divisor is u64, do_div() truncates it to 32 bits, this means it
> can test non-zero and be truncated to zero for division.
>
> fix do_div.cocci warning:
> do_div() does a 64-by-32 division, please consider using div64_u64 instead.
>
> Signed-off-by: Wang Qing <wangqing@vivo.com>
> ---
>  drivers/net/wireless/ath/wil6210/debugfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
> index 4c944e5..2cee9dd
> --- a/drivers/net/wireless/ath/wil6210/debugfs.c
> +++ b/drivers/net/wireless/ath/wil6210/debugfs.c
> @@ -1766,7 +1766,7 @@ __acquires(&p->tid_rx_lock) __releases(&p->tid_rx_lock)
>  			seq_puts(s, "\n");
>  			if (!num_packets)
>  				continue;
> -			do_div(tx_latency_avg, num_packets);
> +			div64_u64(tx_latency_avg, num_packets);

As you have been pointed out in your other patches, do_div() and
div64_u64() work differently.

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

  parent reply	other threads:[~2022-02-10 12:16 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-09  8:39 [PATCH] net: wireless: ath: use div64_u64() instead of do_div() Qing Wang
2022-02-10  6:40 ` Kalle Valo
2022-02-10 12:16 ` Kalle Valo [this message]
2022-02-11 12:23   ` David Laight

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