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From: Liam Howlett <liam.howlett@oracle.com>
To: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"kernel-janitors@vger.kernel.org"
	<kernel-janitors@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] lib: maple_tree: remove unneeded initialization in mtree_range_walk()
Date: Wed, 26 Oct 2022 14:25:21 +0000	[thread overview]
Message-ID: <20221026142514.ipe6rm6ekyh2rre6@revolver> (raw)
In-Reply-To: <20221026120029.12555-2-lukas.bulwahn@gmail.com>


Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>

* Lukas Bulwahn <lukas.bulwahn@gmail.com> [221026 08:01]:
> Before the do-while loop in mtree_range_walk(), the variables next, min,
> max need to be initialized. The variables last, prev_min and prev_max are
> set within the loop body before they are eventually used after exiting the
> loop body.
> 
> As it is a do-while loop, the loop body is executed at least once, so the
> variables last, prev_min and prev_max do not need to be initialized before
> the loop body.
> 
> Remove unneeded initialization of last and prev_min.
> 
> The needless initialization was reported by clang-analyzer as Dead Stores.
> 
> As the compiler already identifies these assignments as unneeded, it
> optimizes the assignments away. Hence:
> 
> No functional change. No change in object code.
> 
> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> ---
>  lib/maple_tree.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index e1743803c851..fbde494444b8 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -2903,8 +2903,8 @@ static inline void *mtree_range_walk(struct ma_state *mas)
>  	unsigned long max, min;
>  	unsigned long prev_max, prev_min;
>  
> -	last = next = mas->node;
> -	prev_min = min = mas->min;
> +	next = mas->node;
> +	min = mas->min;
>  	max = mas->max;
>  	do {
>  		offset = 0;
> -- 
> 2.17.1
> 

  reply	other threads:[~2022-10-26 14:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-26 12:00 [PATCH 0/1] Dead stores in maple-tree Lukas Bulwahn
2022-10-26 12:00 ` [PATCH 1/1] lib: maple_tree: remove unneeded initialization in mtree_range_walk() Lukas Bulwahn
2022-10-26 14:25   ` Liam Howlett [this message]
2022-10-26 14:23 ` [PATCH 0/1] Dead stores in maple-tree Liam Howlett
2022-10-27  7:43   ` Dan Carpenter
2022-10-27 17:16     ` Liam Howlett

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