2.4.22pre3 / pwc / emi disconnect == oops, workaround

@@ -209,7 +209,12 @@
 	unsigned int cmd, unsigned long arg)
 {
 	struct video_device *vfl = video_devdata(file);
-	int err=vfl->ioctl(vfl, cmd, (void *)arg);
+	int err;
+
+	if (!vfl)
+		return -EINVAL;
+	
+	err = vfl->ioctl(vfl, cmd, (void *)arg);
 
 	if(err!=-ENOIOCTLCMD)
 		return err;

@@ -1077,6 +1077,7 @@
 /* Note that all cleanup is done in the reverse order as in _open */
 static void pwc_video_close(struct video_device *vdev)
 {
+        /* Called with BKL held */
 	struct pwc_device *pdev;
 	int i;
 

@@ -1107,17 +1108,16 @@
 				Err("Failed to power down camera (%d)\n", i);
 		}
 	}
-
+	
 	pdev->vopen = 0;
-	if (pdev->decompressor != NULL) {
-		pdev->decompressor->exit();
-		pdev->decompressor->unlock();
-	}
-	pwc_free_buffers(pdev);
-
-	/* wake up _disconnect() routine */
-	if (pdev->unplugged)
-		wake_up(&pdev->remove_ok);
+	
+	if (pdev->unplugged) {
+	  /* Camera was unplugged during use.  Now the user is dead, we can
+	     unregister */
+	  video_unregister_device(pdev->vdev); 
+	  usb_pwc_remove_disconnected(pdev);
+	}
+	
 	Trace(TRACE_OPEN, "<< video_close()\n");
 }
 

@@ -1885,11 +1885,8 @@
 static void usb_pwc_disconnect(struct usb_device *udev, void *ptr)
 {
 	struct pwc_device *pdev;
-	int hint;
-	DECLARE_WAITQUEUE(wait, current);
 
 	lock_kernel();
-	free_mem_leak();
 
 	pdev = (struct pwc_device *)ptr;
 	if (pdev == NULL) {

@@ -1910,53 +1907,41 @@
 		return;
 	}
 #endif	
-	
-	pdev->unplugged = 1;
-	if (pdev->vdev != NULL) {
-		Trace(TRACE_PROBE, "Unregistering video device.\n");
-		video_unregister_device(pdev->vdev); 
-		if (pdev->vopen) {
-			Info("Disconnected while device/video is open!\n");
-			
-			/* Wake up any processes that might be waiting for
-			   a frame, let them return an error condition
-			 */
-			wake_up(&pdev->frameq);
-			
-			/* Wait until we get a 'go' from _close(). This used
-			   to have a gigantic race condition, since we kfree()
-			   stuff here, but we have to wait until close() 
-			   is finished. 
-			 */
-			   
-			Trace(TRACE_PROBE, "Sleeping on remove_ok.\n");
-			add_wait_queue(&pdev->remove_ok, &wait);
-			set_current_state(TASK_UNINTERRUPTIBLE);
-			/* ... wait ... */
-			schedule();
-			remove_wait_queue(&pdev->remove_ok, &wait);
-			set_current_state(TASK_RUNNING);
-			Trace(TRACE_PROBE, "Done sleeping.\n");
-			set_mem_leak(pdev->vdev);
-			pdev->vdev = NULL;
-		}
-		else {
-			/* Normal disconnect; remove from available devices */
-			kfree(pdev->vdev);
-			pdev->vdev = NULL;
-		}
-	}
 
-	/* search device_hint[] table if we occupy a slot, by any chance */
-	for (hint = 0; hint < MAX_DEV_HINTS; hint++)
-		if (device_hint[hint].pdev == pdev)
-			device_hint[hint].pdev = NULL;
-
-	pdev->udev = NULL;
+	if (!pdev->user) {
+	  Trace(TRACE_PROBE, "Unregistering video device.\n");
+	  video_unregister_device(pdev->vdev); 
+	  usb_pwc_remove_disconnected(pdev);
+	} else {
+	  Trace(TRACE_PROBE, "Disconnect while open - defer until close.\n");
+	  pdev->unplugged = 1;
+	}
+	
 	unlock_kernel();
-	kfree(pdev);
 }
 
+static inline void usb_pwc_remove_disconnected(struct pwc_device *pdev)
+{
+  int hint;
+  
+  /* search device_hint[] table if we occupy a slot, by any chance */
+  for (hint = 0; hint < MAX_DEV_HINTS; hint++)
+    if (device_hint[hint].pdev == pdev)
+      device_hint[hint].pdev = NULL;
+  
+  if (pdev->decompressor != NULL) {
+    pdev->decompressor->exit();
+    pdev->decompressor->unlock();
+  }
+  pwc_free_buffers(pdev);
+  
+  /* Normal disconnect; remove from available devices */
+  free_mem_leak();
+  kfree(pdev->vdev);
+  pdev->vdev = NULL;
+  pdev->udev = NULL;
+  kfree(pdev);
+}
 
 /* *grunt* We have to do atoi ourselves :-( */
 static int pwc_atoi(const char *s)

@@ -94,6 +94,7 @@
 
 static void *usb_pwc_probe(struct usb_device *udev, unsigned int ifnum, const struct usb_device_id *id);
 static void usb_pwc_disconnect(struct usb_device *udev, void *ptr);
+static inline void usb_pwc_remove_disconnected(struct pwc_device *pdev);
 
 static struct usb_driver pwc_driver =
 {