backing: silence compiler warning using __printf

__printf marker was added in commit d2cc4dde9206 ("bdi_register: add
__printf verification, fix arg mismatch") for function `bdi_register`
since it is useful to verify format and arguments. Apply equivalent gcc
attribute to `bdi_register_va`.

Remove warning triggered with W=1:

  mm/backing-dev.c:881:2: warning: function might be possible candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 3e4ce54..0e9c0f7 100644 (file)
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -28,6 +28,7 @@ void bdi_put(struct backing_dev_info *bdi);
 
 __printf(2, 3)
 int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);
+__printf(2, 0)
 int bdi_register_va(struct backing_dev_info *bdi, const char *fmt,
                    va_list args);
 int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);