On Fri 27-10-17 01:35:36, weiping zhang wrote:
> this patch add a check for bdi_debug_root and do error handle for it.
> we should make sure it was created success, otherwise when add new
> block device's bdi folder(eg, 8:0) will be create a debugfs root directory.
>
> Signed-off-by: weiping zhang <zhangweiping@xxxxxxxxxxxxxxx>
> ---
> mm/backing-dev.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
These functions get called only on system boot - ENOMEM in those cases is
generally considered fatal and oopsing is acceptable result. So I don't
think this patch is needed.
Honza
>
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index 74b52dfd5852..5072be19d9b2 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -36,9 +36,12 @@ struct workqueue_struct *bdi_wq;
>
> static struct dentry *bdi_debug_root;
>
> -static void bdi_debug_init(void)
> +static int bdi_debug_init(void)
> {
> bdi_debug_root = debugfs_create_dir("bdi", NULL);
> + if (!bdi_debug_root)
> + return -ENOMEM;
> + return 0;
> }
>
> static int bdi_debug_stats_show(struct seq_file *m, void *v)
> @@ -126,8 +129,9 @@ static void bdi_debug_unregister(struct backing_dev_info *bdi)
> debugfs_remove(bdi->debug_dir);
> }
> #else
> -static inline void bdi_debug_init(void)
> +static inline int bdi_debug_init(void)
> {
> + return 0;
> }
> static inline void bdi_debug_register(struct backing_dev_info *bdi,
> const char *name)
> @@ -229,12 +233,19 @@ ATTRIBUTE_GROUPS(bdi_dev);
>
> static __init int bdi_class_init(void)
> {
> + int ret;
> +
> bdi_class = class_create(THIS_MODULE, "bdi");
> if (IS_ERR(bdi_class))
> return PTR_ERR(bdi_class);
>
> bdi_class->dev_groups = bdi_dev_groups;
> - bdi_debug_init();
> + ret = bdi_debug_init();
> + if (ret) {
> + class_destroy(bdi_class);
> + bdi_class = NULL;
> + return ret;
> + }
>
> return 0;
> }
> --
> 2.14.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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