Commit 50d6b9d5 authored by Andy Shevchenko's avatar Andy Shevchenko
Browse files

auxdisplay: linedisp: Use unique number for id 



The absence of decrementation of linedisp_id is incorrect in two ways,
i.e. it may cause:
- an ID exhaustion
- (and if the above is addressed) a duplicate id number may be allocated
  next time a device is added

Replace above mentioned approach by using IDA framework.

Reviewed-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Tested-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent 2327960f

drivers/auxdisplay/line-display.c

+10 −3
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <generated/utsrelease.h>



#include <linux/device.h>

#include <linux/idr.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/string.h>
@@ -188,11 +189,14 @@ static struct attribute *linedisp_attrs[] = { 
};

ATTRIBUTE_GROUPS(linedisp);



static DEFINE_IDA(linedisp_id);



static void linedisp_release(struct device *dev)

{

	struct linedisp *linedisp = container_of(dev, struct linedisp, dev);



	kfree(linedisp->message);

	ida_free(&linedisp_id, linedisp->id);

}



static const struct device_type linedisp_type = {
@@ -214,7 +218,6 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent, 
		      unsigned int num_chars, char *buf,

		      void (*update)(struct linedisp *linedisp))

{

	static atomic_t linedisp_id = ATOMIC_INIT(-1);

	int err;



	memset(linedisp, 0, sizeof(*linedisp));
@@ -225,9 +228,13 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent, 
	linedisp->num_chars = num_chars;

	linedisp->scroll_rate = DEFAULT_SCROLL_RATE;



	err = ida_alloc(&linedisp_id, GFP_KERNEL);

	if (err < 0)

		return err;

	linedisp->id = err;



	device_initialize(&linedisp->dev);

	dev_set_name(&linedisp->dev, "linedisp.%lu",

		     (unsigned long)atomic_inc_return(&linedisp_id));

	dev_set_name(&linedisp->dev, "linedisp.%u", linedisp->id);



	/* initialise a timer for scrolling the message */

	timer_setup(&linedisp->timer, linedisp_scroll, 0);

drivers/auxdisplay/line-display.h

+2 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
 * @message_len: the length of the @message string

 * @scroll_pos: index of the first character of @message currently displayed

 * @scroll_rate: scroll interval in jiffies

 * @id: instance id of this display

 */

struct linedisp {

	struct device dev;
@@ -33,6 +34,7 @@ struct linedisp { 
	unsigned int message_len;

	unsigned int scroll_pos;

	unsigned int scroll_rate;

	unsigned int id;

};



int linedisp_register(struct linedisp *linedisp, struct device *parent,