[PATCH 5/5] drivers: char: Replace bit operation functions with IDA allocator.

[Varsha Rao]

Replace bit operation functions with IDA allocator functions. As IDA
allocation is simpler.

Signed-off-by: Varsha Rao <rvarsha...@gmail.com>
---
 drivers/char/misc.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index c9cd1ea..5786281 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 DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS);
+static DEFINE_IDA(misc_minors_ida);
 
 #ifdef CONFIG_PROC_FS
 static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
@@ -193,14 +193,18 @@ int misc_register(struct miscdevice *misc)
        mutex_lock(&misc_mtx);
 
        if (is_dynamic) {
-               int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS);
+               int i = ida_simple_get(&misc_minors_ida, 0,
+                                      DYNAMIC_MINORS, GFP_KERNEL);
 
                if (i >= DYNAMIC_MINORS) {
                        err = -EBUSY;
                        goto out;
-               }
+               } else if (i < 0) {
+                       err = i;
+                       goto out;
+               } else {
                misc->minor = DYNAMIC_MINORS - i - 1;
-               set_bit(i, misc_minors);
+               }
        } else {
                struct miscdevice *c;
 
@@ -222,7 +226,7 @@ int misc_register(struct miscdevice *misc)
                        int i = DYNAMIC_MINORS - misc->minor - 1;
 
                        if (i < DYNAMIC_MINORS && i >= 0)
-                               clear_bit(i, misc_minors);
+                               ida_simple_remove(&misc_minors_ida, i);
                        misc->minor = MISC_DYNAMIC_MINOR;
                }
                err = PTR_ERR(misc->this_device);
@@ -258,7 +262,7 @@ void misc_deregister(struct miscdevice *misc)
        list_del(&misc->list);
        device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
        if (i < DYNAMIC_MINORS && i >= 0)
-               clear_bit(i, misc_minors);
+               ida_simple_remove(&misc_minors_ida, i);
        mutex_unlock(&misc_mtx);
 }
 
-- 
2.9.3