linux-kernel - Re: [PATCH] Fix reversed logic in drivers/md/md.c

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Date:	Tue, 26 May 2015 14:58:31 +1000
From:	NeilBrown <neilb@...e.de>
To:	Eddie Kovsky <ewk@...ovsky.org>
Cc:	linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Fix reversed logic in drivers/md/md.c

On Mon, 25 May 2015 22:36:24 -0600 Eddie Kovsky <ewk@...ovsky.org> wrote:

> Fixes the following compiler warning in next-20150525 using gcc 5.1.0:
> 
> drivers/md/md.c: In function ‘update_array_info’:
> drivers/md/md.c:6394:26: warning: logical not is only applied to the
> left hand side of comparison [-Wlogical-not-parentheses]
>       !mddev->persistent  != info->not_persistent||
> 
> Signed-off-by: Eddie Kovsky <ewk@...ovsky.org>
> ---
>  drivers/md/md.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index eb27b2a74492..b0f98b5b8985 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -6391,7 +6391,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
>  	    mddev->ctime         != info->ctime         ||
>  	    mddev->level         != info->level         ||
>  /*	    mddev->layout        != info->layout        || */
> -	    !mddev->persistent	 != info->not_persistent||
> +	    mddev->persistent	 == info->not_persistent||
>  	    mddev->chunk_sectors != info->chunk_size >> 9 ||
>  	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
>  	    ((state^info->state) & 0xfffffe00)

Thanks... but I'd rather gcc was fixed. :-(  There is nothing wrong with the
code and it does not deserve a warning.

I really like the column of "!=" and I don't want to change that.

I *might* be able to access
    (!mddev->persistent)   !=  info->not_persistent

Thanks,
NeilBrown

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