1 files changed, 21 insertions, 5 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 91ebb007416c..f7f163557aa0 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -82,6 +82,9 @@
 static LIST_HEAD(loop_devices);
 static DEFINE_MUTEX(loop_devices_mutex);
 
+static int max_part;
+static int part_shift;
+
 /*
  * Transfer functions
  */
@@ -692,6 +695,8 @@ static int loop_change_fd(struct loop_device *lo, struct file *lo_file,
                 goto out_putf;
 
         fput(old_file);
+        if (max_part > 0)
+                ioctl_by_bdev(bdev, BLKRRPART, 0);
         return 0;
 
  out_putf:
@@ -819,6 +824,8 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
         }
         lo->lo_state = Lo_bound;
         wake_up_process(lo->lo_thread);
+        if (max_part > 0)
+                ioctl_by_bdev(bdev, BLKRRPART, 0);
         return 0;
 
 out_clr:
@@ -919,6 +926,8 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
         fput(filp);
         /* This is safe: open() is still holding a reference. */
         module_put(THIS_MODULE);
+        if (max_part > 0)
+                ioctl_by_bdev(bdev, BLKRRPART, 0);
         return 0;
 }
 
@@ -1360,6 +1369,8 @@ static struct block_device_operations lo_fops = {
 static int max_loop;
 module_param(max_loop, int, 0);
 MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
+module_param(max_part, int, 0);
+MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
 
@@ -1412,7 +1423,7 @@ static struct loop_device *loop_alloc(int i)
         if (!lo->lo_queue)
                 goto out_free_dev;
 
-        disk = lo->lo_disk = alloc_disk(1);
+        disk = lo->lo_disk = alloc_disk(1 << part_shift);
         if (!disk)
                 goto out_free_queue;
 
@@ -1422,7 +1433,7 @@ static struct loop_device *loop_alloc(int i)
         init_waitqueue_head(&lo->lo_event);
         spin_lock_init(&lo->lo_lock);
         disk->major             = LOOP_MAJOR;
-        disk->first_minor       = i;
+        disk->first_minor       = i << part_shift;
         disk->fops              = &lo_fops;
         disk->private_data      = lo;
         disk->queue             = lo->lo_queue;
@@ -1502,7 +1513,12 @@ static int __init loop_init(void)
          *     themselves and have kernel automatically instantiate actual
          *     device on-demand.
          */
-        if (max_loop > 1UL << MINORBITS)
+
+        part_shift = 0;
+        if (max_part > 0)
+                part_shift = fls(max_part);
+
+        if (max_loop > 1UL << (MINORBITS - part_shift))
                 return -EINVAL;
 
         if (max_loop) {
@@ -1510,7 +1526,7 @@ static int __init loop_init(void)
                 range = max_loop;
         } else {
                 nr = 8;
-                range = 1UL << MINORBITS;
+                range = 1UL << (MINORBITS - part_shift);
         }
 
         if (register_blkdev(LOOP_MAJOR, "loop"))
@@ -1549,7 +1565,7 @@ static void __exit loop_exit(void)
         unsigned long range;
         struct loop_device *lo, *next;
 
-        range = max_loop ? max_loop :  1UL << MINORBITS;
+        range = max_loop ? max_loop :  1UL << (MINORBITS - part_shift);
 
         list_for_each_entry_safe(lo, next, &loop_devices, lo_list)
                 loop_del_one(lo);