Re: [PATCH 16/49] writeback: reorganize mm/backing-dev.c

[Jan Kara]

On Mon 06-04-15 15:58:05, Tejun Heo wrote:
> Move wb_shutdown(), bdi_register(), bdi_register_dev(),
> bdi_prune_sb(), bdi_remove_from_list() and bdi_unregister() so that
> init / exit functions are grouped together.  This will make updating
> init / exit paths for cgroup writeback support easier.
> 
> This is pure source file reorganization.
  OK.
Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza
> 
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx>
> ---
>  mm/backing-dev.c | 174 +++++++++++++++++++++++++++----------------------------
>  1 file changed, 87 insertions(+), 87 deletions(-)
> 
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index 597f0ce..ff85ecb 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -286,93 +286,6 @@ void wb_wakeup_delayed(struct bdi_writeback *wb)
>  }
>  
>  /*
> - * Remove bdi from bdi_list, and ensure that it is no longer visible
> - */
> -static void bdi_remove_from_list(struct backing_dev_info *bdi)
> -{
> -	spin_lock_bh(&bdi_lock);
> -	list_del_rcu(&bdi->bdi_list);
> -	spin_unlock_bh(&bdi_lock);
> -
> -	synchronize_rcu_expedited();
> -}
> -
> -int bdi_register(struct backing_dev_info *bdi, struct device *parent,
> -		const char *fmt, ...)
> -{
> -	va_list args;
> -	struct device *dev;
> -
> -	if (bdi->dev)	/* The driver needs to use separate queues per device */
> -		return 0;
> -
> -	va_start(args, fmt);
> -	dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
> -	va_end(args);
> -	if (IS_ERR(dev))
> -		return PTR_ERR(dev);
> -
> -	bdi->dev = dev;
> -
> -	bdi_debug_register(bdi, dev_name(dev));
> -	set_bit(WB_registered, &bdi->wb.state);
> -
> -	spin_lock_bh(&bdi_lock);
> -	list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
> -	spin_unlock_bh(&bdi_lock);
> -
> -	trace_writeback_bdi_register(bdi);
> -	return 0;
> -}
> -EXPORT_SYMBOL(bdi_register);
> -
> -int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
> -{
> -	return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
> -}
> -EXPORT_SYMBOL(bdi_register_dev);
> -
> -/*
> - * Remove bdi from the global list and shutdown any threads we have running
> - */
> -static void wb_shutdown(struct bdi_writeback *wb)
> -{
> -	/* Make sure nobody queues further work */
> -	spin_lock_bh(&wb->work_lock);
> -	if (!test_and_clear_bit(WB_registered, &wb->state)) {
> -		spin_unlock_bh(&wb->work_lock);
> -		return;
> -	}
> -	spin_unlock_bh(&wb->work_lock);
> -
> -	/*
> -	 * Drain work list and shutdown the delayed_work.  !WB_registered
> -	 * tells wb_workfn() that @wb is dying and its work_list needs to
> -	 * be drained no matter what.
> -	 */
> -	mod_delayed_work(bdi_wq, &wb->dwork, 0);
> -	flush_delayed_work(&wb->dwork);
> -	WARN_ON(!list_empty(&wb->work_list));
> -}
> -
> -/*
> - * Called when the device behind @bdi has been removed or ejected.
> - *
> - * We can't really do much here except for reducing the dirty ratio at
> - * the moment.  In the future we should be able to set a flag so that
> - * the filesystem can handle errors at mark_inode_dirty time instead
> - * of only at writeback time.
> - */
> -void bdi_unregister(struct backing_dev_info *bdi)
> -{
> -	if (WARN_ON_ONCE(!bdi->dev))
> -		return;
> -
> -	bdi_set_min_ratio(bdi, 0);
> -}
> -EXPORT_SYMBOL(bdi_unregister);
> -
> -/*
>   * Initial write bandwidth: 100 MB/s
>   */
>  #define INIT_BW		(100 << (20 - PAGE_SHIFT))
> @@ -418,6 +331,29 @@ static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
>  	return 0;
>  }
>  
> +/*
> + * Remove bdi from the global list and shutdown any threads we have running
> + */
> +static void wb_shutdown(struct bdi_writeback *wb)
> +{
> +	/* Make sure nobody queues further work */
> +	spin_lock_bh(&wb->work_lock);
> +	if (!test_and_clear_bit(WB_registered, &wb->state)) {
> +		spin_unlock_bh(&wb->work_lock);
> +		return;
> +	}
> +	spin_unlock_bh(&wb->work_lock);
> +
> +	/*
> +	 * Drain work list and shutdown the delayed_work.  !WB_registered
> +	 * tells wb_workfn() that @wb is dying and its work_list needs to
> +	 * be drained no matter what.
> +	 */
> +	mod_delayed_work(bdi_wq, &wb->dwork, 0);
> +	flush_delayed_work(&wb->dwork);
> +	WARN_ON(!list_empty(&wb->work_list));
> +}
> +
>  static void wb_exit(struct bdi_writeback *wb)
>  {
>  	int i;
> @@ -449,6 +385,70 @@ int bdi_init(struct backing_dev_info *bdi)
>  }
>  EXPORT_SYMBOL(bdi_init);
>  
> +int bdi_register(struct backing_dev_info *bdi, struct device *parent,
> +		const char *fmt, ...)
> +{
> +	va_list args;
> +	struct device *dev;
> +
> +	if (bdi->dev)	/* The driver needs to use separate queues per device */
> +		return 0;
> +
> +	va_start(args, fmt);
> +	dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
> +	va_end(args);
> +	if (IS_ERR(dev))
> +		return PTR_ERR(dev);
> +
> +	bdi->dev = dev;
> +
> +	bdi_debug_register(bdi, dev_name(dev));
> +	set_bit(WB_registered, &bdi->wb.state);
> +
> +	spin_lock_bh(&bdi_lock);
> +	list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
> +	spin_unlock_bh(&bdi_lock);
> +
> +	trace_writeback_bdi_register(bdi);
> +	return 0;
> +}
> +EXPORT_SYMBOL(bdi_register);
> +
> +int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
> +{
> +	return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
> +}
> +EXPORT_SYMBOL(bdi_register_dev);
> +
> +/*
> + * Remove bdi from bdi_list, and ensure that it is no longer visible
> + */
> +static void bdi_remove_from_list(struct backing_dev_info *bdi)
> +{
> +	spin_lock_bh(&bdi_lock);
> +	list_del_rcu(&bdi->bdi_list);
> +	spin_unlock_bh(&bdi_lock);
> +
> +	synchronize_rcu_expedited();
> +}
> +
> +/*
> + * Called when the device behind @bdi has been removed or ejected.
> + *
> + * We can't really do much here except for reducing the dirty ratio at
> + * the moment.  In the future we should be able to set a flag so that
> + * the filesystem can handle errors at mark_inode_dirty time instead
> + * of only at writeback time.
> + */
> +void bdi_unregister(struct backing_dev_info *bdi)
> +{
> +	if (WARN_ON_ONCE(!bdi->dev))
> +		return;
> +
> +	bdi_set_min_ratio(bdi, 0);
> +}
> +EXPORT_SYMBOL(bdi_unregister);
> +
>  void bdi_destroy(struct backing_dev_info *bdi)
>  {
>  	/* make sure nobody finds us on the bdi_list anymore */
> -- 
> 2.1.0
> 
-- 
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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