Re: [RESEND PATCH v5 2/5] mtd: ubi: use 'max_bad_blocks' to compute bad_peb_limit if available

From	Brian Norris <computersforpeace@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [RESEND PATCH v5 2/5] mtd: ubi: use 'max_bad_blocks' to compute bad_peb_limit if available
Date	2016-11-22 19:50 +0100
Message-ID	<sGoiJ-2wz-1@gated-at.bofh.it> (permalink)
References	<sG2UW-5ut-5@gated-at.bofh.it> <sG2UW-5ut-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Nov 21, 2016 at 01:51:36PM -0600, Zach Brown wrote:
> From: Jeff Westfahl <jeff.westfahl@ni.com>
> 
> Use the MTD function 'max_bad_blocks' to compute the UBI bad_peb_limit,
> if the function is implemented for an MTD and doesn't return an error.

I'm not exactly a UBI expert here, but it seems reasonable that we
should adjust the Kconfig documentation for MTD_UBI_BEB_LIMIT to further
emphasize that it's a default, if the value can't be determined by other
means.

> Signed-off-by: Jeff Westfahl <jeff.westfahl@ni.com>
> Signed-off-by: Zach Brown <zach.brown@ni.com>
> Acked-by: Boris Brezillon <boris.brezillon@free-electron.com>
> ---
>  drivers/mtd/ubi/build.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
> index 85d54f3..e9940a9 100644
> --- a/drivers/mtd/ubi/build.c
> +++ b/drivers/mtd/ubi/build.c
> @@ -584,6 +584,10 @@ static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
>  	int limit, device_pebs;
>  	uint64_t device_size;
>  
> +	limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
> +	if (limit > 0)
> +		return limit;

Are you sure you want to even override the user-provided
max_beb_per1024 value taken from the mtd= line? I'd think if someone
went as far as to specify this in the kernel command line, they don't
expect it to get overridden. Just my two cents.

Brian

> +
>  	if (!max_beb_per1024)
>  		return 0;
>  
> -- 
> 2.7.4
>

Thread

[RESEND PATCH v5 2/5] mtd: ubi: use 'max_bad_blocks' to compute bad_peb_limit if available Zach Brown <zach.brown@ni.com> - 2016-11-21 21:00 +0100
  Re: [RESEND PATCH v5 2/5] mtd: ubi: use 'max_bad_blocks' to compute  bad_peb_limit if available Brian Norris <computersforpeace@gmail.com> - 2016-11-22 19:50 +0100
  Re: [RESEND PATCH v5 2/5] mtd: ubi: use 'max_bad_blocks' to compute  bad_peb_limit if available Brian Norris <computersforpeace@gmail.com> - 2016-11-22 20:00 +0100

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