[dm-devel] dm: fix blk-mq request-based DM queue initialization
Mike Snitzer
snitzer at redhat.com
Thu Apr 30 12:47:41 UTC 2015
On Thu, Apr 30 2015 at 4:23am -0400,
Christoph Hellwig <hch at lst.de> wrote:
> On Thu, Apr 30, 2015 at 09:22:00AM +0200, Christoph Hellwig wrote:
> > Well - we're obviously trying to reinitialize it here and only error
> > out very low level with your patch. What I mean is that we shouldn't
> > even try to reinitialize it at a much higher level, so we don't need
> > this blk-mq specific hack down here.
OK, understood.
> FYI, this fixes the isssue for me and seems to be "more correct" at
> a higher level:
Yeah, I like this. Means the early return in
dm_init_request_based_queue() can be removed too.
> ---
> From: Christoph Hellwig <hch at lst.de>
> Subject: [PATCH] dm: only initialize request_queue once
>
> We should only inіnitialize the request_queue on the initial table load when
> we assing the device type.
"assing" ;) Will fix up and also add that this patch fixes the issue
you reported, thanks.
> Signed-off-by: Christoph Hellwig <hch at lst.de>
>
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index c8a18e4..de92662 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -1298,21 +1298,22 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
> goto err_unlock_md_type;
> }
>
> - if (dm_get_md_type(md) == DM_TYPE_NONE)
> + if (dm_get_md_type(md) == DM_TYPE_NONE) {
> /* Initial table load: acquire type of table. */
> dm_set_md_type(md, dm_table_get_type(t));
> - else if (dm_get_md_type(md) != dm_table_get_type(t)) {
> +
> + /* setup md->queue to reflect md's type (may block) */
> + r = dm_setup_md_queue(md);
> + if (r) {
> + DMWARN("unable to set up device queue for new table.");
> + goto err_unlock_md_type;
> + }
> + } else if (dm_get_md_type(md) != dm_table_get_type(t)) {
> DMWARN("can't change device type after initial table load.");
> r = -EINVAL;
> goto err_unlock_md_type;
> }
>
> - /* setup md->queue to reflect md's type (may block) */
> - r = dm_setup_md_queue(md);
> - if (r) {
> - DMWARN("unable to set up device queue for new table.");
> - goto err_unlock_md_type;
> - }
> dm_unlock_md_type(md);
>
> /* stage inactive table */
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