1 files changed, 25 insertions, 0 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 13893aa2ac9d..c0d5f6945c1e 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -115,6 +115,7 @@ struct hd_struct {
 #else
         struct disk_stats dkstats;
 #endif
+        atomic_t ref;
         struct rcu_head rcu_head;
 };
 
@@ -597,6 +598,7 @@ extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
                                                      sector_t len, int flags,
                                                      struct partition_meta_info
                                                        *info);
+extern void __delete_partition(struct hd_struct *);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);
 
@@ -625,6 +627,29 @@ extern ssize_t part_fail_store(struct device *dev,
                                const char *buf, size_t count);
 #endif /* CONFIG_FAIL_MAKE_REQUEST */
 
+static inline void hd_ref_init(struct hd_struct *part)
+{
+        atomic_set(&part->ref, 1);
+        smp_mb();
+}
+
+static inline void hd_struct_get(struct hd_struct *part)
+{
+        atomic_inc(&part->ref);
+        smp_mb__after_atomic_inc();
+}
+
+static inline int hd_struct_try_get(struct hd_struct *part)
+{
+        return atomic_inc_not_zero(&part->ref);
+}
+
+static inline void hd_struct_put(struct hd_struct *part)
+{
+        if (atomic_dec_and_test(&part->ref))
+                __delete_partition(part);
+}
+
 #else /* CONFIG_BLOCK */
 
 static inline void printk_all_partitions(void) { }