Date:   Thu, 26 Jan 2023 14:52:58 +0100
From:   Jan Kara <jack@suse.cz>
To:     Maxim Korotkov <korotkov.maxim.s@gmail.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Jens Axboe <axboe@fb.com>, Tejun Heo <tj@kernel.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        lvc-project@linuxtesting.org
Subject: Re: [PATCH] writeback: fix call of incorrect macro
Message-ID: <20230126135258.zpvyfxc2ffhzzsnx@quack3>
References: <20230119104443.3002-1-korotkov.maxim.s@gmail.com>
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On Thu 19-01-23 13:44:43, Maxim Korotkov wrote:
>  the variable 'history' is of type u16, it may be an error 
>  that the hweight32 macro was used for it 
>  I guess macro hweight16 should be used
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 2a81490811d0 ("writeback: implement foreign cgroup inode detection")
> Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>

Looks good to me, although it is mostly a theoretical issue - I don't see
how hweight32 could do any harm here. Anyway, feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/fs-writeback.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 6fba5a52127b..fc16123b2405 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -829,7 +829,7 @@ void wbc_detach_inode(struct writeback_control *wbc)
>  		 * is okay.  The main goal is avoiding keeping an inode on
>  		 * the wrong wb for an extended period of time.
>  		 */
> -		if (hweight32(history) > WB_FRN_HIST_THR_SLOTS)
> +		if (hweight16(history) > WB_FRN_HIST_THR_SLOTS)
>  			inode_switch_wbs(inode, max_id);
>  	}
>  
> -- 
> 2.37.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR