block: hide badblocks attribute by default

Commit 2c2db7df64ff "block: Add badblock management for gendisks"
allowed for drivers like pmem and software-raid to advertise a list of
bad media areas. However, it inadvertently added a 'badblocks' to all
block devices. Lets clean this up by having the 'badblocks' attribute
not be visible when the driver has not populated a 'struct badblocks'
instance in the gendisk.

Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/genhd.c b/block/genhd.c
index 510aac1486cba038c7cf6653fbe9577899b3813a..9a2d01abfa3b453058dd1c44f36cf4647757d7c4 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1060,8 +1060,19 @@ static struct attribute *disk_attrs[] = {
        NULL
 };
 
+static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+       struct device *dev = container_of(kobj, typeof(*dev), kobj);
+       struct gendisk *disk = dev_to_disk(dev);
+
+       if (a == &dev_attr_badblocks.attr && !disk->bb)
+               return 0;
+       return a->mode;
+}
+
 static struct attribute_group disk_attr_group = {
        .attrs = disk_attrs,
+       .is_visible = disk_visible,
 };
 
 static const struct attribute_group *disk_attr_groups[] = {