linux-kernel - Re: [PATCH 07/11] xfs: remove not needed freezing calls

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Date:   Thu, 30 Nov 2017 17:21:55 +0100
From:   Jan Kara <jack@...e.cz>
To:     "Luis R. Rodriguez" <mcgrof@...nel.org>
Cc:     viro@...iv.linux.org.uk, bart.vanassche@....com,
        ming.lei@...hat.com, tytso@....edu, darrick.wong@...cle.com,
        jikos@...nel.org, rjw@...ysocki.net, pavel@....cz,
        len.brown@...el.com, linux-fsdevel@...r.kernel.org,
        boris.ostrovsky@...cle.com, jgross@...e.com,
        todd.e.brandt@...ux.intel.com, nborisov@...e.com, jack@...e.cz,
        martin.petersen@...cle.com, ONeukum@...e.com,
        oleksandr@...alenko.name, oleg.b.antonyan@...il.com,
        yu.chen.surf@...il.com, dan.j.williams@...el.com,
        linux-pm@...r.kernel.org, linux-block@...r.kernel.org,
        linux-xfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/11] xfs: remove not needed freezing calls

On Wed 29-11-17 15:23:52, Luis R. Rodriguez wrote:
> This removes superflous freezer calls as they are no longer needed
> as the VFS now performs filesystem freezing/thaw if the filesystem has
> support for it.
> 
> The following Coccinelle rule was used as follows:
> 
> spatch --sp-file fs-freeze-cleanup.cocci --in-place fs/$FS/

I think your rule misses WQ_FREEZABLE flag for workqueues? That would be
also good to get rid of...

								Honza

> 
> @ has_freeze_fs @
> identifier super_ops;
> expression freeze_op;
> @@
> 
> struct super_operations super_ops = {
> 	.freeze_fs = freeze_op,
> };
> 
> @ remove_set_freezable depends on has_freeze_fs @
> expression time;
> statement S, S2, S3;
> expression task;
> @@
> 
> (
> -	set_freezable();
> |
> -	if (try_to_freeze())
> -		continue;
> |
> -	try_to_freeze();
> |
> -	freezable_schedule();
> +	schedule();
> |
> -	freezable_schedule_timeout(time);
> +	schedule_timeout(time);
> |
> -	if (freezing(task)) { S }
> |
> -	if (freezing(task)) { S }
> -	else
> 	{ S2 }
> |
> -	freezing(current)
> )
> 
> Generated-by: Coccinelle SmPL
> Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>
> ---
>  fs/xfs/xfs_trans_ail.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
> index cef89f7127d3..1f3dd10a9d00 100644
> --- a/fs/xfs/xfs_trans_ail.c
> +++ b/fs/xfs/xfs_trans_ail.c
> @@ -513,7 +513,6 @@ xfsaild(
>  	long		tout = 0;	/* milliseconds */
>  
>  	current->flags |= PF_MEMALLOC;
> -	set_freezable();
>  
>  	while (1) {
>  		if (tout && tout <= 20)
> @@ -551,19 +550,17 @@ xfsaild(
>  		if (!xfs_ail_min(ailp) &&
>  		    ailp->xa_target == ailp->xa_target_prev) {
>  			spin_unlock(&ailp->xa_lock);
> -			freezable_schedule();
> +			schedule();
>  			tout = 0;
>  			continue;
>  		}
>  		spin_unlock(&ailp->xa_lock);
>  
>  		if (tout)
> -			freezable_schedule_timeout(msecs_to_jiffies(tout));
> +			schedule_timeout(msecs_to_jiffies(tout));
>  
>  		__set_current_state(TASK_RUNNING);
>  
> -		try_to_freeze();
> -
>  		tout = xfsaild_push(ailp);
>  	}
>  
> -- 
> 2.15.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR