Date:   Wed, 25 Jan 2023 10:10:52 +0100
From:   Jan Kara <jack@suse.cz>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jan Kara <jack@suse.cz>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] fs: move sb_init_dio_done_wq out of direct-io.c
Message-ID: <20230125091052.fam755fliaq2tann@quack3>
References: <20230125065839.191256-1-hch@lst.de>
 <20230125065839.191256-2-hch@lst.de>
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On Wed 25-01-23 07:58:38, Christoph Hellwig wrote:
> sb_init_dio_done_wq is also used by the iomap code, so move it to
> super.c in preparation for building direct-io.c conditionally.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/direct-io.c | 24 ------------------------
>  fs/internal.h  |  4 +---
>  fs/super.c     | 24 ++++++++++++++++++++++++
>  3 files changed, 25 insertions(+), 27 deletions(-)
> 
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index 03d381377ae10a..ab0d7ea89813a6 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -558,30 +558,6 @@ static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio)
>  	return ret;
>  }
>  
> -/*
> - * Create workqueue for deferred direct IO completions. We allocate the
> - * workqueue when it's first needed. This avoids creating workqueue for
> - * filesystems that don't need it and also allows us to create the workqueue
> - * late enough so the we can include s_id in the name of the workqueue.
> - */
> -int sb_init_dio_done_wq(struct super_block *sb)
> -{
> -	struct workqueue_struct *old;
> -	struct workqueue_struct *wq = alloc_workqueue("dio/%s",
> -						      WQ_MEM_RECLAIM, 0,
> -						      sb->s_id);
> -	if (!wq)
> -		return -ENOMEM;
> -	/*
> -	 * This has to be atomic as more DIOs can race to create the workqueue
> -	 */
> -	old = cmpxchg(&sb->s_dio_done_wq, NULL, wq);
> -	/* Someone created workqueue before us? Free ours... */
> -	if (old)
> -		destroy_workqueue(wq);
> -	return 0;
> -}
> -
>  static int dio_set_defer_completion(struct dio *dio)
>  {
>  	struct super_block *sb = dio->inode->i_sb;
> diff --git a/fs/internal.h b/fs/internal.h
> index a803cc3cf716ab..cb0c0749661aae 100644
> --- a/fs/internal.h
> +++ b/fs/internal.h
> @@ -120,6 +120,7 @@ extern bool trylock_super(struct super_block *sb);
>  struct super_block *user_get_super(dev_t, bool excl);
>  void put_super(struct super_block *sb);
>  extern bool mount_capable(struct fs_context *);
> +int sb_init_dio_done_wq(struct super_block *sb);
>  
>  /*
>   * open.c
> @@ -187,9 +188,6 @@ extern void mnt_pin_kill(struct mount *m);
>   */
>  extern const struct dentry_operations ns_dentry_operations;
>  
> -/* direct-io.c: */
> -int sb_init_dio_done_wq(struct super_block *sb);
> -
>  /*
>   * fs/stat.c:
>   */
> diff --git a/fs/super.c b/fs/super.c
> index 12c08cb20405d5..904adfbacdcf3c 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -1764,3 +1764,27 @@ int thaw_super(struct super_block *sb)
>  	return thaw_super_locked(sb);
>  }
>  EXPORT_SYMBOL(thaw_super);
> +
> +/*
> + * Create workqueue for deferred direct IO completions. We allocate the
> + * workqueue when it's first needed. This avoids creating workqueue for
> + * filesystems that don't need it and also allows us to create the workqueue
> + * late enough so the we can include s_id in the name of the workqueue.
> + */
> +int sb_init_dio_done_wq(struct super_block *sb)
> +{
> +	struct workqueue_struct *old;
> +	struct workqueue_struct *wq = alloc_workqueue("dio/%s",
> +						      WQ_MEM_RECLAIM, 0,
> +						      sb->s_id);
> +	if (!wq)
> +		return -ENOMEM;
> +	/*
> +	 * This has to be atomic as more DIOs can race to create the workqueue
> +	 */
> +	old = cmpxchg(&sb->s_dio_done_wq, NULL, wq);
> +	/* Someone created workqueue before us? Free ours... */
> +	if (old)
> +		destroy_workqueue(wq);
> +	return 0;
> +}
> -- 
> 2.39.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR