[dm-devel] [PATCH v2 2/4] md-raid0: conditional mddev->queue access to suit dm-raid

[Brassow Jonathan]

> On Apr 29, 2015, at 7:03 AM, heinzm at redhat.com wrote:
> 
> From: Heinz Mauelshagen <heinzm at redhat.com>
> 
> 
> This patch is a prerequisite for dm-raid "raid0" support to allow
> dm-raid to access the MD RAID0 personality doing unconditional
> accesses to mddev->queue, which is NULL in case of dm-raid stacked
> on top of MD.
> 
> Most of the conditional mddev->queue accesses made it to upstream
> but this missing one, which prohibits md raid0 to set disk stack limits
> (being done in dm core in case of md underneath dm).
> 
> 
> Signed-off-by: Heinz Mauelshagen <heinzm at redhat.com>
> Tested-by: Heinz Mauelshagen <heinzm at redhat.com>
> 
> ---
> drivers/md/raid0.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index 2cb59a6..6a68ef5 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -188,8 +188,9 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
> 		}
> 		dev[j] = rdev1;
> 
> -		disk_stack_limits(mddev->gendisk, rdev1->bdev,
> -				  rdev1->data_offset << 9);
> +		if (mddev->queue)
> +			disk_stack_limits(mddev->gendisk, rdev1->bdev,
> +					  rdev1->data_offset << 9);
> 
> 		if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)
> 			conf->has_merge_bvec = 1;

Aren’t you missing a condition?

>From the code:
        /*
         * now since we have the hard sector sizes, we can make sure
         * chunk size is a multiple of that sector size
         */
        if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
                printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
                       mdname(mddev),
                       mddev->chunk_sectors << 9);
                goto abort;
        }

        if (mddev->queue) {

Shouldn’t that ‘queue_logical_block_size be inside the lower ‘if’?

 brassow