linux-kernel - Re: [PATCH 04/10] ext4: use is_power_of_2 helper in ext4_mb_regular

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Message-Id: <87a5vpl1h3.fsf@doe.com>
Date:   Fri, 21 Jul 2023 21:07:44 +0530
From:   Ritesh Harjani (IBM) <ritesh.list@...il.com>
To:     Kemeng Shi <shikemeng@...weicloud.com>, tytso@....edu,
        adilger.kernel@...ger.ca, ojaswin@...ux.ibm.com,
        linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     shikemeng@...weicloud.com
Subject: Re: [PATCH 04/10] ext4: use is_power_of_2 helper in ext4_mb_regular_allocator

Kemeng Shi <shikemeng@...weicloud.com> writes:

> Use intuitive is_power_of_2 helper in ext4_mb_regular_allocator.
>
> Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
> ---
>  fs/ext4/mballoc.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>

Looks good to me. Feel free to add:

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>

> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 4031f8e2a660..b838944b5f09 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2795,10 +2795,7 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
>  	 * requests upto maximum buddy size we have constructed.
>  	 */
>  	if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) {
> -		/*
> -		 * This should tell if fe_len is exactly power of 2
> -		 */
> -		if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
> +		if (is_power_of_2(ac->ac_g_ex.fe_len))
>  			ac->ac_2order = array_index_nospec(i - 1,
>  							   MB_NUM_ORDERS(sb));
>  	}
> -- 
> 2.30.0