1 files changed, 26 insertions, 5 deletions

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index f517869e8d10..772b2ed8d239 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -312,14 +312,18 @@ static void delete_partition_rcu_cb(struct rcu_head *head)
 
 void delete_partition(struct gendisk *disk, int partno)
 {
+        struct disk_part_tbl *ptbl = disk->part_tbl;
         struct hd_struct *part;
 
-        part = disk->__part[partno];
+        if (partno >= ptbl->len)
+                return;
+
+        part = ptbl->part[partno];
         if (!part)
                 return;
 
         blk_free_devt(part_devt(part));
-        rcu_assign_pointer(disk->__part[partno], NULL);
+        rcu_assign_pointer(ptbl->part[partno], NULL);
         kobject_put(part->holder_dir);
         device_del(part_to_dev(part));
 
@@ -341,10 +345,16 @@ int add_partition(struct gendisk *disk, int partno,
         dev_t devt = MKDEV(0, 0);
         struct device *ddev = disk_to_dev(disk);
         struct device *pdev;
+        struct disk_part_tbl *ptbl;
         const char *dname;
         int err;
 
-        if (disk->__part[partno])
+        err = disk_expand_part_tbl(disk, partno);
+        if (err)
+                return err;
+        ptbl = disk->part_tbl;
+
+        if (ptbl->part[partno])
                 return -EBUSY;
 
         p = kzalloc(sizeof(*p), GFP_KERNEL);
@@ -398,7 +408,7 @@ int add_partition(struct gendisk *disk, int partno,
 
         /* everything is up and running, commence */
         INIT_RCU_HEAD(&p->rcu_head);
-        rcu_assign_pointer(disk->__part[partno], p);
+        rcu_assign_pointer(ptbl->part[partno], p);
 
         /* suppress uevent if the disk supresses it */
         if (!ddev->uevent_suppress)
@@ -487,7 +497,7 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
         struct disk_part_iter piter;
         struct hd_struct *part;
         struct parsed_partitions *state;
-        int p, res;
+        int p, highest, res;
 
         if (bdev->bd_part_count)
                 return -EBUSY;
@@ -511,6 +521,17 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
         /* tell userspace that the media / partition table may have changed */
         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 
+        /* Detect the highest partition number and preallocate
+         * disk->part_tbl.  This is an optimization and not strictly
+         * necessary.
+         */
+        for (p = 1, highest = 0; p < state->limit; p++)
+                if (state->parts[p].size)
+                        highest = p;
+
+        disk_expand_part_tbl(disk, highest);
+
+        /* add partitions */
         for (p = 1; p < state->limit; p++) {
                 sector_t size = state->parts[p].size;
                 sector_t from = state->parts[p].from;