Re: Regression in xen-blkfront regarding sector sizes

[Rusty Bird <rustybird@net-c.com>]

Christoph Hellwig:
> On Mon, Jun 24, 2024 at 04:29:15PM +0200, Jürgen Groß wrote:
> >> Rusty suspects it's related to
> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/block/xen-blkfront.c?id=ba3f67c1163812b5d7ec33705c31edaa30ce6c51,
> >> so I'm cc-ing people mentioned there too.
> >
> > I think the call of blkif_set_queue_limits() in this patch should NOT precede
> > setting of info->sector_size and info->physical_sector_size, as those are
> > needed by blkif_set_queue_limits().
> 
> Yes.  Something like the patch below should fix it.  We could also stop
> passing sector_size and physіcal_sector_size to xlvbd_alloc_gendisk to
> clean things up a bit more.
> 
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index fd7c0ff2139cee..9f3d68044f8882 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -1133,6 +1133,8 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
>  	if (err)
>  		goto out_release_minors;
>  
> +	info->sector_size = sector_size;
> +	info->physical_sector_size = physical_sector_size;
>  	blkif_set_queue_limits(info, &lim);
>  	gd = blk_mq_alloc_disk(&info->tag_set, &lim, info);
>  	if (IS_ERR(gd)) {
> @@ -1159,8 +1161,6 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
>  
>  	info->rq = gd->queue;
>  	info->gd = gd;
> -	info->sector_size = sector_size;
> -	info->physical_sector_size = physical_sector_size;
>  
>  	xlvbd_flush(info);
>  
> 
> 

With this patch applied on top of v6.9.4, I get the correct
logical/physical block sizes and the issue is fixed. Thank you!

Rusty