On Fri, Apr 07, 2017 at 05:04:41PM +0530, Varsha Rao wrote:
> Replace bit operation functions with IDA allocator functions. As IDA
> allocation is simpler.
But why does this matter?
>
> 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);
> + }
Your indentation is now incorrect :(
> } 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);
As much as I like the ida interface, I don't see why it is required to
use it here, you have not provided any justification for this patch at
all :(
thanks,
greg k-h
