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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()
Thread-Topic: [PATCH 1/1] lib: maple_tree: remove unneeded initialization in
 mtree_range_walk()
Thread-Index: AQHY6TKlbfwgc8LED0+rTJD3nSzgSK4guyEA
Date:   Wed, 26 Oct 2022 14:25:21 +0000
Message-ID: <20221026142514.ipe6rm6ekyh2rre6@revolver>
References: <20221026120029.12555-1-lukas.bulwahn@gmail.com>
 <20221026120029.12555-2-lukas.bulwahn@gmail.com>
In-Reply-To: <20221026120029.12555-2-lukas.bulwahn@gmail.com>
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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 th=
e
> loop body.
>=20
> 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 befor=
e
> the loop body.
>=20
> Remove unneeded initialization of last and prev_min.
>=20
> The needless initialization was reported by clang-analyzer as Dead Stores=
.
>=20
> As the compiler already identifies these assignments as unneeded, it
> optimizes the assignments away. Hence:
>=20
> No functional change. No change in object code.
>=20
> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> ---
>  lib/maple_tree.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>=20
> 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_stat=
e *mas)
>  	unsigned long max, min;
>  	unsigned long prev_max, prev_min;
> =20
> -	last =3D next =3D mas->node;
> -	prev_min =3D min =3D mas->min;
> +	next =3D mas->node;
> +	min =3D mas->min;
>  	max =3D mas->max;
>  	do {
>  		offset =3D 0;
> --=20
> 2.17.1
> =