[PATCH 3/4] bdi: add error handle for bdi_debug_register

[weiping zhang]

In order to make error handle more cleaner we call bdi_debug_register
before set state to WB_registered, that we can avoid call bdi_unregister
in release_bdi().

Signed-off-by: weiping zhang <zhangweip...@didichuxing.com>
---
 mm/backing-dev.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index e9d6a1ede12b..54396d53f471 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -893,10 +893,13 @@ int bdi_register_va(struct backing_dev_info *bdi, const 
char *fmt, va_list args)
        if (IS_ERR(dev))
                return PTR_ERR(dev);
 
+       if (bdi_debug_register(bdi, dev_name(dev))) {
+               device_destroy(bdi_class, dev->devt);
+               return -ENOMEM;
+       }
        cgwb_bdi_register(bdi);
        bdi->dev = dev;
 
-       bdi_debug_register(bdi, dev_name(dev));
        set_bit(WB_registered, &bdi->wb.state);
 
        spin_lock_bh(&bdi_lock);
@@ -916,6 +919,8 @@ int bdi_register(struct backing_dev_info *bdi, const char 
*fmt, ...)
        va_start(args, fmt);
        ret = bdi_register_va(bdi, fmt, args);
        va_end(args);
+       if (ret)
+               bdi_put(bdi);
        return ret;
 }
 EXPORT_SYMBOL(bdi_register);
-- 
2.14.2