From: Frank Mori Hess <fmhess@speakeasy.net>
Date: Mon, 20 Oct 2008 20:35:40 +0000 (+0000)
Subject: Fixed some module reference counting problems due to comedi_device_attach
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=f4b2196f9180dbe0ce3e34fe63e526709fbc1d69;p=comedi.git

Fixed some module reference counting problems due to comedi_device_attach
and detach assuming the caller needs them to call module_get/module_put
for them.
---

diff --git a/comedi/comedi_fops.c b/comedi/comedi_fops.c
index c1fbcb26..1634fdad 100644
--- a/comedi/comedi_fops.c
+++ b/comedi/comedi_fops.c
@@ -193,7 +193,12 @@ static int do_devconfig_ioctl(comedi_device * dev, comedi_devconfig * arg)
 	if (arg == NULL) {
 		if (is_device_busy(dev))
 			return -EBUSY;
-		comedi_device_detach(dev);
+		if(dev->attached)
+		{
+			struct module *driver_module = dev->driver->module;
+			comedi_device_detach(dev);
+			module_put(driver_module);
+		}
 		return 0;
 	}
 
@@ -229,6 +234,13 @@ static int do_devconfig_ioctl(comedi_device * dev, comedi_devconfig * arg)
 	}
 
 	ret = comedi_device_attach(dev, &it);
+	if(ret == 0)
+	{
+		if(!try_module_get(dev->driver->module)) {
+			comedi_device_detach(dev);
+			return -ENOSYS;
+		}
+	}
 
 	if (aux_data)
 		vfree(aux_data);
@@ -1782,7 +1794,7 @@ static int comedi_open(struct inode *inode, struct file *file)
 		mutex_unlock(&dev->mutex);
 		return -ENODEV;
 	}
-      ok:
+ok:
 	__module_get(THIS_MODULE);
 
 	if (dev->attached) {
@@ -2084,8 +2096,7 @@ void comedi_device_cleanup(comedi_device *dev)
 {
 	if(dev == NULL) return;
 	mutex_lock(&dev->mutex);
-	if (dev->attached)
-		comedi_device_detach(dev);
+	comedi_device_detach(dev);
 	mutex_unlock(&dev->mutex);
 	mutex_destroy(&dev->mutex);
 }
diff --git a/comedi/drivers.c b/comedi/drivers.c
index 53987db3..f6636bee 100644
--- a/comedi/drivers.c
+++ b/comedi/drivers.c
@@ -143,6 +143,7 @@ int comedi_device_attach(comedi_device * dev, comedi_devconfig * it)
 		dev->driver = driv;
 		ret = driv->attach(dev, it);
 		if (ret < 0) {
+			module_put(dev->driver->module);
 			__comedi_device_detach(dev);
 			return ret;
 		}
@@ -164,6 +165,7 @@ int comedi_device_attach(comedi_device * dev, comedi_devconfig * it)
 attached:
 	/* do a little post-config cleanup */
 	ret = postconfig(dev);
+	module_put(dev->driver->module);
 	if (ret < 0) {
 		__comedi_device_detach(dev);
 		return ret;
@@ -175,7 +177,6 @@ attached:
 	}
 	smp_wmb();
 	dev->attached = 1;
-	module_put(dev->driver->module);
 
 	return 0;
 }