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Message-Id: <20200814150522.C0936C43391@smtp.codeaurora.org>
Date: Fri, 14 Aug 2020 15:05:22 +0000 (UTC)
From: Kalle Valo <kvalo@...eaurora.org>
To: Julia Lawall <Julia.Lawall@...ia.fr>
Cc: kernel-janitors@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 7/7] ath: drop unnecessary list_empty
Julia Lawall <Julia.Lawall@...ia.fr> wrote:
> list_for_each_entry{_safe} is able to handle an empty list.
> The only effect of avoiding the loop is not initializing the
> index variable.
> Drop list_empty tests in cases where these variables are not
> used.
>
> Note that list_for_each_entry{_safe} is defined in terms of
> list_first_entry, which indicates that it should not be used on an
> empty list. But in list_for_each_entry{_safe}, the element obtained
> by list_first_entry is not really accessed, only the address of its
> list_head field is compared to the address of the list head, so the
> list_first_entry is safe.
>
> The semantic patch that makes this change for the list_for_each_entry
> case is as follows: (http://coccinelle.lip6.fr/)
>
> <smpl>
> @@
> expression x,e;
> statement S;
> identifier i;
> @@
>
> -if (!(list_empty(x)))
> list_for_each_entry(i,x,...) S
> ... when != i
> ? i = e
> </smpl>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@...ia.fr>
> Signed-off-by: Kalle Valo <kvalo@...eaurora.org>
Patch applied to ath-next branch of ath.git, thanks.
18c25b4019ca ath: drop unnecessary list_empty
--
https://patchwork.kernel.org/patch/11685677/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
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