Input: fix open/close races in joystick drivers - add a semaphore

       to the ones that register more than one input device.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 16 insertions, 13 deletions

diff --git a/drivers/input/joystick/amijoy.c b/drivers/input/joystick/amijoy.c
index cf36ca9b92f3..033456bb9fe0 100644
--- a/drivers/input/joystick/amijoy.c
+++ b/drivers/input/joystick/amijoy.c
@@ -51,7 +51,8 @@ MODULE_PARM_DESC(map, "Map of attached joysticks in form of <a>,<b> (default is
 
 __obsolete_setup("amijoy=");
 
-static int amijoy_used[2] = { 0, 0 };
+static int amijoy_used;
+static DECLARE_MUTEX(amijoy_sem);
 static struct input_dev amijoy_dev[2];
 static char *amijoy_phys[2] = { "amijoy/input0", "amijoy/input1" };
 
@@ -84,26 +85,30 @@ static irqreturn_t amijoy_interrupt(int irq, void *dummy, struct pt_regs *fp)
 
 static int amijoy_open(struct input_dev *dev)
 {
-        int *used = dev->private;
+        int err;
 
-        if ((*used)++)
-                return 0;
+        err = down_interruptible(&amijoy_sem);
+        if (err)
+                return err;
 
-        if (request_irq(IRQ_AMIGA_VERTB, amijoy_interrupt, 0, "amijoy", amijoy_interrupt)) {
-                (*used)--;
+        if (!amijoy_used && request_irq(IRQ_AMIGA_VERTB, amijoy_interrupt, 0, "amijoy", amijoy_interrupt)) {
                 printk(KERN_ERR "amijoy.c: Can't allocate irq %d\n", IRQ_AMIGA_VERTB);
-                return -EBUSY;
+                err = -EBUSY;
+                goto out;
         }
 
-        return 0;
+        amijoy_used++;
+out:
+        up(&amijoy_sem);
+        return err;
 }
 
 static void amijoy_close(struct input_dev *dev)
 {
-        int *used = dev->private;
-
-        if (!--(*used))
+        down(&amijoysem);
+        if (!--amijoy_used)
                 free_irq(IRQ_AMIGA_VERTB, amijoy_interrupt);
+        up(&amijoy_sem);
 }
 
 static int __init amijoy_init(void)
@@ -138,8 +143,6 @@ static int __init amijoy_init(void)
                         amijoy_dev[i].id.product = 0x0003;
                         amijoy_dev[i].id.version = 0x0100;
 
-                        amijoy_dev[i].private = amijoy_used + i;
-
                         input_register_device(amijoy_dev + i);
                         printk(KERN_INFO "input: %s at joy%ddat\n", amijoy_name, i);
                 }