Re: [PATCH] fs: ubifs: remove always-false check

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

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Hello Ahmad,

On Thu, Aug 11, 2022 at 03:58:04PM +0200, Ahmad Fatoum wrote:
> GCC correctly warns that two bit wide compr_type can't
> exceed or be equal to UBIFS_COMPR_TYPES_CNT (== 4).
> 
> Remove the check. The check is there in the kernel as well,
> but the warning is disabled there.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  fs/ubifs/super.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> index b48e21fae636..6a0074bd1a5c 100644
> --- a/fs/ubifs/super.c
> +++ b/fs/ubifs/super.c
> @@ -86,11 +86,6 @@ static int validate_inode(struct ubifs_info *c, const struct inode *inode)
>  		return 1;
>  	}
>  
> -	if (ui->compr_type >= UBIFS_COMPR_TYPES_CNT) {
> -		ubifs_err(c, "unknown compression type %d", ui->compr_type);
> -		return 2;
> -	}
> -

I taked to Richard Weinberger about this check in the kernel via irc:

1656326473 < ukleinek> derRichard: I don't feel like increasing my
	kernel patch count, so I'm just reporting here:
	https://lore.barebox.org/20220624081628.GD1615@pengutronix.de
1656326538 <@derRichard> oh
1656326817 <@derRichard> yeah looks like we need to enlarge struct
	ubifs_inode
1656327489 < sha> derRichard: Only when the next compression type comes
1656327499 < sha> derRichard: For now it's enough to remove the check
1656328989 <@derRichard> sha: yeah, i'd rather keep the check.
1656329007 <@derRichard> if we add a new type we'll forget to re-add the
	check for sure
1656330552 < sha> derRichard: Ah, I thought the on-flash format has two
	bits, but it's only the in-memory structures. Then we can change
	the width to 3 bits without problem
1656331100 <@derRichard> exactly
1656331149 <@derRichard> i think it is anyway time ot reevaluate the
	bitfields in struct ubifs_inode, i'm not so sure whether they
	really pay off these days

Given the kernel wants to keep the check, maybe it's easier to keep it
in barebox, too?!

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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