3 files changed, 27 insertions, 15 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 85df45292dba..0c706f33a599 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1284,7 +1284,11 @@ struct gendisk *alloc_disk_node(int minors, int node_id)
                  * converted to make use of bd_mutex and sequence counters.
                  */
                 seqcount_init(&disk->part0.nr_sects_seq);
-                hd_ref_init(&disk->part0);
+                if (hd_ref_init(&disk->part0)) {
+                        hd_free_part(&disk->part0);
+                        kfree(disk);
+                        return NULL;
+                }
 
                 disk->minors = minors;
                 rand_initialize_disk(disk);
diff --git a/block/partition-generic.c b/block/partition-generic.c
index eca0d02a607c..e7711133284e 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -232,8 +232,9 @@ static void delete_partition_rcu_cb(struct rcu_head *head)
         put_device(part_to_dev(part));
 }
 
-void __delete_partition(struct hd_struct *part)
+void __delete_partition(struct percpu_ref *ref)
 {
+        struct hd_struct *part = container_of(ref, struct hd_struct, ref);
         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 }
 
@@ -254,7 +255,7 @@ void delete_partition(struct gendisk *disk, int partno)
         kobject_put(part->holder_dir);
         device_del(part_to_dev(part));
 
-        hd_struct_put(part);
+        hd_struct_kill(part);
 }
 
 static ssize_t whole_disk_show(struct device *dev,
@@ -355,8 +356,8 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
         if (!dev_get_uevent_suppress(ddev))
                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 
-        hd_ref_init(p);
-        return p;
+        if (!hd_ref_init(p))
+                return p;
 
 out_free_info:
         free_part_info(p);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index a221220ffcb2..2adbfa6d02bc 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -13,6 +13,7 @@
 #include <linux/kdev_t.h>
 #include <linux/rcupdate.h>
 #include <linux/slab.h>
+#include <linux/percpu-refcount.h>
 
 #ifdef CONFIG_BLOCK
 
@@ -124,7 +125,7 @@ struct hd_struct {
 #else
         struct disk_stats dkstats;
 #endif
-        atomic_t ref;
+        struct percpu_ref ref;
         struct rcu_head rcu_head;
 };
 
@@ -611,7 +612,7 @@ 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 percpu_ref *);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);
 
@@ -640,33 +641,39 @@ 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)
+static inline int hd_ref_init(struct hd_struct *part)
 {
-        atomic_set(&part->ref, 1);
-        smp_mb();
+        if (percpu_ref_init(&part->ref, __delete_partition, 0,
+                                GFP_KERNEL))
+                return -ENOMEM;
+        return 0;
 }
 
 static inline void hd_struct_get(struct hd_struct *part)
 {
-        atomic_inc(&part->ref);
-        smp_mb__after_atomic();
+        percpu_ref_get(&part->ref);
 }
 
 static inline int hd_struct_try_get(struct hd_struct *part)
 {
-        return atomic_inc_not_zero(&part->ref);
+        return percpu_ref_tryget_live(&part->ref);
 }
 
 static inline void hd_struct_put(struct hd_struct *part)
 {
-        if (atomic_dec_and_test(&part->ref))
-                __delete_partition(part);
+        percpu_ref_put(&part->ref);
+}
+
+static inline void hd_struct_kill(struct hd_struct *part)
+{
+        percpu_ref_kill(&part->ref);
 }
 
 static inline void hd_free_part(struct hd_struct *part)
 {
         free_part_stats(part);
         free_part_info(part);
+        percpu_ref_exit(&part->ref);
 }
 
 /*