From: Miklos Szeredi <mszeredi@suse.cz>

This managed to completely evade testing :(

Fix return value to be count or -errno.  Also bring the function in
line with the other store functions on this object, which have more
strict input checking.

Also fix bdi_set_max_ratio() to actually return an error, instead of
always zero.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page-writeback.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/page-writeback.c~mm-bdi-allow-setting-a-maximum-for-the-bdi-dirty-limit-fix mm/page-writeback.c
--- a/mm/page-writeback.c~mm-bdi-allow-setting-a-maximum-for-the-bdi-dirty-limit-fix
+++ a/mm/page-writeback.c
@@ -288,7 +288,7 @@ int bdi_set_max_ratio(struct backing_dev
 	}
 	spin_unlock_irqrestore(&bdi_lock, flags);
 
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(bdi_set_max_ratio);
 
_