[PATCH 1/2] devfs: take into account for the partitions check that mtd is different

[Sascha Hauer]

On Mon, Jul 11, 2022 at 11:09:14AM +0200, Uwe Kleine-König wrote:
> mtd partitions are separate devices. Their partition info is relative to
> these subdevices and so offset is 0 for them. This needs to be taken
> into account for the overlap check.
> 
> Fixes: 7f9f45b9bfef ("devfs: Do not create overlapping partitions")
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> ---
>  fs/devfs-core.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/fs/devfs-core.c b/fs/devfs-core.c
> index 38423e5d1e07..dca5e10191d4 100644
> --- a/fs/devfs-core.c
> +++ b/fs/devfs-core.c
> @@ -395,9 +395,20 @@ static bool region_overlap(loff_t starta, loff_t lena,
>  static int check_overlap(struct cdev *cdev, const char *name, loff_t offset, loff_t size)
>  {
>  	struct cdev *cpart;
> +	loff_t cpart_offset;
>  
>  	list_for_each_entry(cpart, &cdev->partitions, partition_entry) {
> -		if (region_overlap(cpart->offset, cpart->size,
> +		cpart_offset = cpart->offset;
> +
> +		/*
> +		 * An mtd partition is represented by a separate cdev and its
> +		 * cpart is relative to this one. So its .offset is 0 and we
> +		 * have to consult .master_offset to get its offset.
> +		 */
> +		if (cpart->mtd)
> +			cpart_offset = cpart->mtd->master_offset;
> +
> +		if (region_overlap(cpart_offset, cpart->size,
>  				   offset, size))
>  			goto conflict;
>  	}
> @@ -408,7 +419,7 @@ conflict:
>  	pr_err("New partition %s (0x%08llx-0x%08llx) on %s "
>  		"overlaps with partition %s (0x%08llx-0x%08llx), not creating it\n",
>  		name, offset, offset + size - 1, cpart->name,
> -		cpart->name, cpart->offset, cpart->offset + cpart->size - 1);
> +		cpart->name, cpart_offset, cpart_offset + cpart->size - 1);
>  
>  	return -EINVAL;
>  }
> -- 
> 2.36.1
> 
> 
> 

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