[dm-devel] [PATCH 1/7] dm mpath: do not call pg_init when it is already running

[Junichi Nomura]

On 02/04/14 05:28, Mike Snitzer wrote:
> From: Hannes Reinecke <hare at suse.de>
> 
> When pg_init is running we shouldn't be calling the same
> routine twice; we need to wait for the first pg_init to
> complete.
> 
> Signed-off-by: Hannes Reinecke <hare at suse.de>
> Signed-off-by: Mike Snitzer <snitzer at redhat.com>
> ---
>  drivers/md/dm-mpath.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index 6eb9dc9..304ee5c 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -261,6 +261,9 @@ static void __pg_init_all_paths(struct multipath *m)
>  	struct pgpath *pgpath;
>  	unsigned long pg_init_delay = 0;
>  
> +	if (m->pg_init_in_progress || m->pg_init_disabled)
> +		return;
> +
>  	m->pg_init_count++;
>  	m->pg_init_required = 0;
>  	if (m->pg_init_delay_retry)
> @@ -501,8 +504,7 @@ static void process_queued_ios(struct work_struct *work)
>  	    (!pgpath && !m->queue_if_no_path))
>  		must_queue = 0;
>  
> -	if (m->pg_init_required && !m->pg_init_in_progress && pgpath &&
> -	    !m->pg_init_disabled)
> +	if (pgpath && m->pg_init_required)
>  		__pg_init_all_paths(m);
>  
>  	spin_unlock_irqrestore(&m->lock, flags);
> 

I think the patch is ok but the description seems not
matching what it does.

This patch moves condition checks as a preparation of following
patches and has no effect on behaviour.
process_queued_ios() is the only caller of __pg_init_all_paths()
and 2 condition checks are moved from outside to inside without
side effects.

Reviewed-by: Jun'ichi Nomura <j-nomura at ce.jp.nec.com>

-- 
Jun'ichi Nomura, NEC Corporation