Currently the lifecycle of bd_holder_dir is problematic, it can be freed
in del_gendisk() while it can still be accessed before disk_release().
And there in no way to know if the kobject if freed by kobject_put() for
now, thus add a new field in bloce_device to manage refcount of
bd_holder_dir seperately.
Prepare to fix the problem in following patch.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/blk.h | 3 +++
block/genhd.c | 27 +++++++++++++++++++++++++++
include/linux/blk_types.h | 1 +
3 files changed, 31 insertions(+)
diff --git a/block/blk.h b/block/blk.h
index d6ea0d1a6db0..fef868b4169c 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -458,6 +458,9 @@ extern const struct address_space_operations def_blk_aops;
int disk_register_independent_access_ranges(struct gendisk *disk);
void disk_unregister_independent_access_ranges(struct gendisk *disk);
+bool bd_try_get_holder_dir(struct block_device *bdev);
+void bd_put_holder_dir(struct block_device *bdev);
+
#ifdef CONFIG_FAIL_MAKE_REQUEST
bool should_fail_request(struct block_device *part, unsigned int bytes);
#else /* CONFIG_FAIL_MAKE_REQUEST */
diff --git a/block/genhd.c b/block/genhd.c
index 17b33c62423d..53f9c8b2690a 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -375,6 +375,33 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
return 0;
}
+bool bd_try_get_holder_dir(struct block_device *bdev)
+{
+ mutex_lock(&bdev->bd_disk->open_mutex);
+ if (!bdev->holder_dir_ref) {
+ mutex_unlock(&bdev->bd_disk->open_mutex);
+ return false;
+ }
+
+ bdev->holder_dir_ref++;
+ mutex_unlock(&bdev->bd_disk->open_mutex);
+ return true;
+}
+
+void bd_put_holder_dir(struct block_device *bdev)
+{
+ mutex_lock(&bdev->bd_disk->open_mutex);
+ if (WARN_ON(bdev->holder_dir_ref <= 0))
+ goto out;
+
+ if (!(--bdev->holder_dir_ref)) {
+ kobject_put(bdev->bd_holder_dir);
+ bdev->bd_holder_dir = NULL;
+ }
+out:
+ mutex_unlock(&bdev->bd_disk->open_mutex);
+}
+
/**
* device_add_disk - add disk information to kernel list
* @parent: parent device for the disk
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index e0b098089ef2..550c8e15af49 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -53,6 +53,7 @@ struct block_device {
int bd_holders;
bool bd_write_holder;
struct kobject *bd_holder_dir;
+ int holder_dir_ref;
u8 bd_partno;
spinlock_t bd_size_lock; /* for bd_inode->i_size updates */
struct gendisk * bd_disk;
--
2.31.1
