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Subject[PATCH 3.18 27/83] Input: xpad - use ida() for finding the pad_nr
Date
3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit e3b651745a03810efffd7ebf2a9b5be65fb70ec3 ]

The pad_nr corresponds to the lit up LED on the controller. Therefore there
should be no gaps when enumerating. Currently a LED is only re-assigned
after a controller is re-connected 4 times.

This patch uses ida to track connected pads - this way we can re-assign
freed up pad number immediately.

Consider the following case:
1. pad A is connected and gets pad_nr = 0
2. pad B is connected and gets pad_nr = 1
3. pad A is disconnected
4. pad A is connected again

using ida_simple_get() controller A now correctly gets pad_nr = 0 again.

Signed-off-by: Pavel Rojtberg <rojtberg@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/input/joystick/xpad.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 60ebd78a49a6..a395980bb816 100644
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -244,7 +244,6 @@ static const signed short xpad_btn_triggers[] = {
-1
};

-
static const signed short xpad360_btn[] = { /* buttons for x360 controller */
BTN_TL, BTN_TR, /* Button LB/RB */
BTN_MODE, /* The big X button */
@@ -347,7 +346,7 @@ struct usb_xpad {

int mapping; /* map d-pad to buttons or to axes */
int xtype; /* type of xbox device */
- unsigned long pad_nr; /* the order x360 pads were attached */
+ int pad_nr; /* the order x360 pads were attached */
};

/*
@@ -883,6 +882,9 @@ static int xpad_init_ff(struct usb_xpad *xpad) { return 0; }

#if defined(CONFIG_JOYSTICK_XPAD_LEDS)
#include <linux/leds.h>
+#include <linux/idr.h>
+
+static DEFINE_IDA(xpad_pad_seq);

struct xpad_led {
char name[16];
@@ -964,7 +966,6 @@ static void xpad_led_set(struct led_classdev *led_cdev,

static int xpad_led_probe(struct usb_xpad *xpad)
{
- static atomic_t led_seq = ATOMIC_INIT(-1);
struct xpad_led *led;
struct led_classdev *led_cdev;
int error;
@@ -976,9 +977,13 @@ static int xpad_led_probe(struct usb_xpad *xpad)
if (!led)
return -ENOMEM;

- xpad->pad_nr = atomic_inc_return(&led_seq);
+ xpad->pad_nr = ida_simple_get(&xpad_pad_seq, 0, 0, GFP_KERNEL);
+ if (xpad->pad_nr < 0) {
+ error = xpad->pad_nr;
+ goto err_free_mem;
+ }

- snprintf(led->name, sizeof(led->name), "xpad%lu", xpad->pad_nr);
+ snprintf(led->name, sizeof(led->name), "xpad%d", xpad->pad_nr);
led->xpad = xpad;

led_cdev = &led->led_cdev;
@@ -986,16 +991,19 @@ static int xpad_led_probe(struct usb_xpad *xpad)
led_cdev->brightness_set = xpad_led_set;

error = led_classdev_register(&xpad->udev->dev, led_cdev);
- if (error) {
- kfree(led);
- xpad->led = NULL;
- return error;
- }
+ if (error)
+ goto err_free_id;

/* Light up the segment corresponding to controller number */
xpad_identify_controller(xpad);
-
return 0;
+
+err_free_id:
+ ida_simple_remove(&xpad_pad_seq, xpad->pad_nr);
+err_free_mem:
+ kfree(led);
+ xpad->led = NULL;
+ return error;
}

static void xpad_led_disconnect(struct usb_xpad *xpad)
@@ -1004,6 +1012,7 @@ static void xpad_led_disconnect(struct usb_xpad *xpad)

if (xpad_led) {
led_classdev_unregister(&xpad_led->led_cdev);
+ ida_simple_remove(&xpad_pad_seq, xpad->pad_nr);
kfree(xpad_led);
}
}
@@ -1013,7 +1022,6 @@ static void xpad_led_disconnect(struct usb_xpad *xpad) { }
static void xpad_identify_controller(struct usb_xpad *xpad) { }
#endif

-
static int xpad_open(struct input_dev *dev)
{
struct usb_xpad *xpad = input_get_drvdata(dev);
--
2.17.1


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