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path: root/drivers/char/misc.c
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Diffstat (limited to 'drivers/char/misc.c')
-rw-r--r--drivers/char/misc.c26
1 files changed, 11 insertions, 15 deletions
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 96f1cd086dd2..94a136e96c06 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -60,9 +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];
-
-extern int pmu_device_init(void);
+static DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS);
#ifdef CONFIG_PROC_FS
static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
@@ -198,24 +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 = DYNAMIC_MINORS - misc->minor - 1;
+ if (i < DYNAMIC_MINORS && i >= 0)
+ clear_bit(i, misc_minors);
err = PTR_ERR(misc->this_device);
goto out;
}
@@ -242,7 +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;
@@ -250,9 +247,8 @@ int misc_deregister(struct miscdevice *misc)
mutex_lock(&misc_mtx);
list_del(&misc->list);
device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
- if (i < DYNAMIC_MINORS && i>0) {
- misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
- }
+ if (i < DYNAMIC_MINORS && i >= 0)
+ clear_bit(i, misc_minors);
mutex_unlock(&misc_mtx);
return 0;
}