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

Jan Kara
2015-04-20T15:34:45Z

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@suse.cz>

Honza
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Wu Fengguang <fengguang.wu@intel.com>
> ---
> 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@suse.cz>
SUSE Labs, CR