Re: linux-next: manual merge of the device-mapper tree with the block tree

[John Garry]

On 18/07/2025 06:10, Stephen Rothwell wrote:
> Hi all,
>
> Today's linux-next merge of the device-mapper tree got a conflict in:
>
>    drivers/md/dm-stripe.c
>
> between commit:
>
>    5fb9d4341b78 ("dm-stripe: limit chunk_sectors to the stripe size")
>
> from the block tree and commit:
>
>    846e9e999dd3 ("dm-stripe: fix a possible integer overflow")
>
> from the device-mapper tree.
>
> I fixed it up (I think - see below) and can carry the fix as necessary.
> This is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.

I think that this is the proper merge resolution:

static void stripe_io_hints(struct dm_target *ti,
    struct queue_limits *limits)
{
	struct stripe_c *sc = ti->private;
	unsigned int io_min, io_opt;

	if (!check_shl_overflow(sc->chunk_size, SECTOR_SHIFT, &io_min) && 
!check_mul_overflow(io_min, sc->stripes, &io_opt)) {
		limits->io_min = io_min;
		limits->io_opt = io_opt;
	}
	limits->chunk_sectors = sc->chunk_size;
}


For purpose of atomic writes, we should always set chunk_sectors.

BTW, I tried to apply the conflicting patches from the block tree on 
-next from 17 July, and I was getting strange behaviour:

# vgcreate vg00 /dev/sda /dev/sdb /dev/sdc /dev/sdd
 WARNING: Unknown logical_block_size for device /dev/sda.
 WARNING: Unknown logical_block_size for device /dev/sdb.
 WARNING: Unknown logical_block_size for device /dev/sdc.
 WARNING: Unknown logical_block_size for device /dev/sdd.
 Physical volume "/dev/sda" successfully created.
 Physical volume "/dev/sdb" successfully created.
 Physical volume "/dev/sdc" successfully created.
 Physical volume "/dev/sdd" successfully created.
 Volume group "vg00" successfully created
#

I had no such problem on Jens' block for-6.17 tree.

Thanks,
John