1 files changed, 9 insertions, 13 deletions

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index a3a02f6303c8..94a136e96c06 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -60,7 +60,7 @@ static DEFINE_MUTEX(misc_mtx);
  * Assigned numbers, used for dynamic minors
  */
 #define DYNAMIC_MINORS 64 /* like dynamic majors */
-static unsigned char misc_minors[DYNAMIC_MINORS / 8];
+static DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS);
 
 #ifdef CONFIG_PROC_FS
 static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
@@ -196,27 +196,23 @@ int misc_register(struct miscdevice * misc)
         }
 
         if (misc->minor == MISC_DYNAMIC_MINOR) {
-                int i = DYNAMIC_MINORS;
-                while (--i >= 0)
-                        if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
-                                break;
-                if (i<0) {
+                int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS);
+                if (i >= DYNAMIC_MINORS) {
                         mutex_unlock(&misc_mtx);
                         return -EBUSY;
                 }
-                misc->minor = i;
+                misc->minor = DYNAMIC_MINORS - i - 1;
+                set_bit(i, misc_minors);
         }
 
-        if (misc->minor < DYNAMIC_MINORS)
-                misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
         dev = MKDEV(MISC_MAJOR, misc->minor);
 
         misc->this_device = device_create(misc_class, misc->parent, dev,
                                           misc, "%s", misc->name);
         if (IS_ERR(misc->this_device)) {
-                int i = misc->minor;
+                int i = DYNAMIC_MINORS - misc->minor - 1;
                 if (i < DYNAMIC_MINORS && i >= 0)
-                        misc_minors[i>>3] &= ~(1 << (i & 7));
+                        clear_bit(i, misc_minors);
                 err = PTR_ERR(misc->this_device);
                 goto out;
         }
@@ -243,7 +239,7 @@ int misc_register(struct miscdevice * misc)
 
 int misc_deregister(struct miscdevice *misc)
 {
-        int i = misc->minor;
+        int i = DYNAMIC_MINORS - misc->minor - 1;
 
         if (list_empty(&misc->list))
                 return -EINVAL;
@@ -252,7 +248,7 @@ int misc_deregister(struct miscdevice *misc)
         list_del(&misc->list);
         device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
         if (i < DYNAMIC_MINORS && i >= 0)
-                misc_minors[i>>3] &= ~(1 << (i & 7));
+                clear_bit(i, misc_minors);
         mutex_unlock(&misc_mtx);
         return 0;
 }