[16/49] rc-core: use an IDA rather than a bitmap

  This patch changes rc-core to use an IDA rather than a bitmap to assign
unique numbers to each rc device. This is in preparation for introducing
rc-core chardevs.

Signed-off-by: David Härdeman <david@hardeman.nu>
---
 drivers/media/rc/ir-raw.c  |    2 +-
 drivers/media/rc/rc-main.c |   40 ++++++++++++++++++++--------------------
 include/media/rc-core.h    |    4 ++--
 3 files changed, 23 insertions(+), 23 deletions(-)


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As I commented on a private e-mail, based on the patch descriptions:

Patch 17 deserves a bigger explanation. Well, the best is if you
could send a separate RFC describing what you have in mind with
patches 16-29, for our discussions, explaining what usage are you
expecting for a non-LIRC chardev, as its description doesn't help
at all, and why LIRC's way doesn't fulfill our needs any more.

Patch 18 looks silly... why to replicate evdev on a separate device?

Patches 19 and 20 might make sense, but why not use LIRC instead?

As patch 16 is also part of this change, I'm skipping those patches
from my review. Please re-submit latter after some RFC discussions
about the API changes that are being proposed by those patches.

Thanks,

Em Fri, 04 Apr 2014 01:32:36 +0200
David Härdeman <david@hardeman.nu> escreveu:

> This patch changes rc-core to use an IDA rather than a bitmap to assign
> unique numbers to each rc device. This is in preparation for introducing
> rc-core chardevs.
> 
> Signed-off-by: David Härdeman <david@hardeman.nu>
> ---
>  drivers/media/rc/ir-raw.c  |    2 +-
>  drivers/media/rc/rc-main.c |   40 ++++++++++++++++++++--------------------
>  include/media/rc-core.h    |    4 ++--
>  3 files changed, 23 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/media/rc/ir-raw.c b/drivers/media/rc/ir-raw.c
> index 2a7f858..aed2997 100644
> --- a/drivers/media/rc/ir-raw.c
> +++ b/drivers/media/rc/ir-raw.c
> @@ -271,7 +271,7 @@ int ir_raw_event_register(struct rc_dev *dev)
>  
>  	spin_lock_init(&dev->raw->lock);
>  	dev->raw->thread = kthread_run(ir_raw_event_thread, dev->raw,
> -				       "rc%ld", dev->devno);
> +				       "rc%u", dev->minor);
>  
>  	if (IS_ERR(dev->raw->thread)) {
>  		rc = PTR_ERR(dev->raw->thread);
> diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
> index 2788102..42268f3 100644
> --- a/drivers/media/rc/rc-main.c
> +++ b/drivers/media/rc/rc-main.c
> @@ -18,17 +18,15 @@
>  #include <linux/input.h>
>  #include <linux/leds.h>
>  #include <linux/slab.h>
> +#include <linux/idr.h>
>  #include <linux/device.h>
>  #include <linux/module.h>
>  #include "rc-core-priv.h"
>  
> -/* Bitmap to store allocated device numbers from 0 to IRRCV_NUM_DEVICES - 1 */
> -#define IRRCV_NUM_DEVICES      256
> -static DECLARE_BITMAP(ir_core_dev_number, IRRCV_NUM_DEVICES);
> -
>  /* Sizes are in bytes, 256 bytes allows for 32 entries on x64 */
>  #define IR_TAB_MIN_SIZE	256
>  #define IR_TAB_MAX_SIZE	8192
> +#define RC_DEV_MAX	256
>  
>  /* FIXME: IR_KEYPRESS_TIMEOUT should be protocol specific */
>  #define IR_KEYPRESS_TIMEOUT 250
> @@ -38,6 +36,9 @@ static LIST_HEAD(rc_map_list);
>  static DEFINE_SPINLOCK(rc_map_lock);
>  static struct led_trigger *led_feedback;
>  
> +/* Used to keep track of rc devices */
> +static DEFINE_IDA(rc_ida);
> +
>  static struct rc_map_list *seek_rc_map(const char *name)
>  {
>  	struct rc_map_list *map = NULL;
> @@ -1442,7 +1443,9 @@ int rc_register_device(struct rc_dev *dev)
>  	static bool raw_init = false; /* raw decoders loaded? */
>  	struct rc_map *rc_map;
>  	const char *path;
> -	int rc, devno, attr = 0;
> +	int attr = 0;
> +	int minor;
> +	int rc;
>  
>  	if (!dev || !dev->map_name)
>  		return -EINVAL;
> @@ -1462,13 +1465,13 @@ int rc_register_device(struct rc_dev *dev)
>  	if (dev->close)
>  		dev->input_dev->close = ir_close;
>  
> -	do {
> -		devno = find_first_zero_bit(ir_core_dev_number,
> -					    IRRCV_NUM_DEVICES);
> -		/* No free device slots */
> -		if (devno >= IRRCV_NUM_DEVICES)
> -			return -ENOMEM;
> -	} while (test_and_set_bit(devno, ir_core_dev_number));
> +	minor = ida_simple_get(&rc_ida, 0, RC_DEV_MAX, GFP_KERNEL);
> +	if (minor < 0)
> +		return minor;
> +
> +	dev->minor = minor;
> +	dev_set_name(&dev->dev, "rc%u", dev->minor);
> +	dev_set_drvdata(&dev->dev, dev);
>  
>  	dev->dev.groups = dev->sysfs_groups;
>  	dev->sysfs_groups[attr++] = &rc_dev_protocol_attr_grp;
> @@ -1488,9 +1491,6 @@ int rc_register_device(struct rc_dev *dev)
>  	 */
>  	mutex_lock(&dev->lock);
>  
> -	dev->devno = devno;
> -	dev_set_name(&dev->dev, "rc%ld", dev->devno);
> -	dev_set_drvdata(&dev->dev, dev);
>  	rc = device_add(&dev->dev);
>  	if (rc)
>  		goto out_unlock;
> @@ -1558,8 +1558,8 @@ int rc_register_device(struct rc_dev *dev)
>  
>  	mutex_unlock(&dev->lock);
>  
> -	IR_dprintk(1, "Registered rc%ld (driver: %s, remote: %s, mode %s)\n",
> -		   dev->devno,
> +	IR_dprintk(1, "Registered rc%u (driver: %s, remote: %s, mode %s)\n",
> +		   dev->minor,
>  		   dev->driver_name ? dev->driver_name : "unknown",
>  		   rc_map->name ? rc_map->name : "unknown",
>  		   dev->driver_type == RC_DRIVER_IR_RAW ? "raw" : "cooked");
> @@ -1578,7 +1578,7 @@ out_dev:
>  	device_del(&dev->dev);
>  out_unlock:
>  	mutex_unlock(&dev->lock);
> -	clear_bit(dev->devno, ir_core_dev_number);
> +	ida_simple_remove(&rc_ida, minor);
>  	return rc;
>  }
>  EXPORT_SYMBOL_GPL(rc_register_device);
> @@ -1590,8 +1590,6 @@ void rc_unregister_device(struct rc_dev *dev)
>  
>  	del_timer_sync(&dev->timer_keyup);
>  
> -	clear_bit(dev->devno, ir_core_dev_number);
> -
>  	if (dev->driver_type == RC_DRIVER_IR_RAW)
>  		ir_raw_event_unregister(dev);
>  
> @@ -1604,6 +1602,8 @@ void rc_unregister_device(struct rc_dev *dev)
>  
>  	device_del(&dev->dev);
>  
> +	ida_simple_remove(&rc_ida, dev->minor);
> +
>  	rc_free_device(dev);
>  }
>  
> diff --git a/include/media/rc-core.h b/include/media/rc-core.h
> index 5a082e7..ca3d836 100644
> --- a/include/media/rc-core.h
> +++ b/include/media/rc-core.h
> @@ -87,7 +87,7 @@ enum rc_filter_type {
>   * @rc_map: current scan/key table
>   * @lock: used to ensure we've filled in all protocol details before
>   *	anyone can call show_protocols or store_protocols
> - * @devno: unique remote control device number
> + * @minor: unique minor remote control device number
>   * @raw: additional data for raw pulse/space devices
>   * @input_dev: the input child device used to communicate events to userspace
>   * @driver_type: specifies if protocol decoding is done in hardware or software
> @@ -147,7 +147,7 @@ struct rc_dev {
>  	const char			*map_name;
>  	struct rc_map			rc_map;
>  	struct mutex			lock;
> -	unsigned long			devno;
> +	unsigned int			minor;
>  	struct ir_raw_event_ctrl	*raw;
>  	struct input_dev		*input_dev;
>  	enum rc_driver_type		driver_type;
> 
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