Input: yealink - reliably kill urbs

Yealink uses two URBs that submit each other. This arrangement
cannot be reliably killed with usb_kill_urb() alone, as there's
a window during which the wrong URB may be killed. The fix is
to introduce a flag.

[dtor@mail.ru: remove spinlock, flag alone should be enough]
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/misc/yealink.c b/drivers/input/misc/yealink.c
index 8a949e7..facefd3 100644 (file)
--- a/drivers/input/misc/yealink.c
+++ b/drivers/input/misc/yealink.c
@@ -119,6 +119,8 @@ struct yealink_dev {
        u8 lcdMap[ARRAY_SIZE(lcdMap)];  /* state of LCD, LED ... */
        int key_code;                   /* last reported key     */
 
+       unsigned int shutdown:1;
+
        int     stat_ix;
        union {
                struct yld_status s;
@@ -424,10 +426,10 @@ send_update:
 static void urb_irq_callback(struct urb *urb)
 {
        struct yealink_dev *yld = urb->context;
-       int ret;
+       int ret, status = urb->status;
 
-       if (urb->status)
-               err("%s - urb status %d", __func__, urb->status);
+       if (status)
+               err("%s - urb status %d", __func__, status);
 
        switch (yld->irq_data->cmd) {
        case CMD_KEYPRESS:
@@ -447,32 +449,37 @@ static void urb_irq_callback(struct urb *urb)
 
        yealink_do_idle_tasks(yld);
 
-       ret = usb_submit_urb(yld->urb_ctl, GFP_ATOMIC);
-       if (ret)
-               err("%s - usb_submit_urb failed %d", __func__, ret);
+       if (!yld->shutdown) {
+               ret = usb_submit_urb(yld->urb_ctl, GFP_ATOMIC);
+               if (ret && ret != -EPERM)
+                       err("%s - usb_submit_urb failed %d", __func__, ret);
+       }
 }
 
 static void urb_ctl_callback(struct urb *urb)
 {
        struct yealink_dev *yld = urb->context;
-       int ret;
+       int ret = 0, status = urb->status;
 
-       if (urb->status)
-               err("%s - urb status %d", __func__, urb->status);
+       if (status)
+               err("%s - urb status %d", __func__, status);
 
        switch (yld->ctl_data->cmd) {
        case CMD_KEYPRESS:
        case CMD_SCANCODE:
                /* ask for a response */
-               ret = usb_submit_urb(yld->urb_irq, GFP_ATOMIC);
+               if (!yld->shutdown)
+                       ret = usb_submit_urb(yld->urb_irq, GFP_ATOMIC);
                break;
        default:
                /* send new command */
                yealink_do_idle_tasks(yld);
-               ret = usb_submit_urb(yld->urb_ctl, GFP_ATOMIC);
+               if (!yld->shutdown)
+                       ret = usb_submit_urb(yld->urb_ctl, GFP_ATOMIC);
+               break;
        }
 
-       if (ret)
+       if (ret && ret != -EPERM)
                err("%s - usb_submit_urb failed %d", __func__, ret);
 }
 
@@ -531,8 +538,18 @@ static void input_close(struct input_dev *dev)
 {
        struct yealink_dev *yld = input_get_drvdata(dev);
 
+       yld->shutdown = 1;
+       /*
+        * Make sure the flag is seen by other CPUs before we start
+        * killing URBs so new URBs won't be submitted
+        */
+       smp_wmb();
+
        usb_kill_urb(yld->urb_ctl);
        usb_kill_urb(yld->urb_irq);
+
+       yld->shutdown = 0;
+       smp_wmb();
 }
 
 /*******************************************************************************
@@ -809,9 +826,6 @@ static int usb_cleanup(struct yealink_dev *yld, int err)
        if (yld == NULL)
                return err;
 
-       usb_kill_urb(yld->urb_irq);     /* parameter validation in core/urb */
-       usb_kill_urb(yld->urb_ctl);     /* parameter validation in core/urb */
-
         if (yld->idev) {
                if (err)
                        input_free_device(yld->idev);