V4L/DVB (5244): Dvbdev: fix illegal re-usage of fileoperations struct

Arjan van de Ven <arjan@infradead.org> reported an illegal re-usage of 
the fileoperations struct if more than one dvb device (e.g. frontend) is 
present. 

This patch fixes this issue.  

It allocates a new fileoperations struct each time a device is 
registered and copies the default template fileops.

Signed-off-by: Marcel Siegert <mws@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/media/dvb/dvb-core/dvbdev.c b/drivers/media/dvb/dvb-core/dvbdev.c
index 826b47f155a0..490337b5ee3e 100644
--- a/drivers/media/dvb/dvb-core/dvbdev.c
+++ b/drivers/media/dvb/dvb-core/dvbdev.c
@@ -199,12 +199,14 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
                         const struct dvb_device *template, void *priv, int type)
 {
         struct dvb_device *dvbdev;
+        struct file_operations *dvbdevfops;
+
         int id;
 
         if (mutex_lock_interruptible(&dvbdev_register_lock))
                 return -ERESTARTSYS;
 
-        if ((id = dvbdev_get_free_id (adap, type)) < 0) {
+        if ((id = dvbdev_get_free_id (adap, type)) < 0){
                 mutex_unlock(&dvbdev_register_lock);
                 *pdvbdev = NULL;
                 printk ("%s: could get find free device id...\n", __FUNCTION__);
@@ -213,7 +215,15 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
 
         *pdvbdev = dvbdev = kmalloc(sizeof(struct dvb_device), GFP_KERNEL);
 
-        if (!dvbdev) {
+        if (!dvbdev){
+                mutex_unlock(&dvbdev_register_lock);
+                return -ENOMEM;
+        }
+
+        dvbdevfops = kzalloc(sizeof(struct file_operations), GFP_KERNEL);
+
+        if (!dvbdevfops){
+                kfree (dvbdev);
                 mutex_unlock(&dvbdev_register_lock);
                 return -ENOMEM;
         }
@@ -223,7 +233,9 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
         dvbdev->id = id;
         dvbdev->adapter = adap;
         dvbdev->priv = priv;
+        dvbdev->fops = dvbdevfops;
 
+        memcpy(dvbdev->fops, template->fops, sizeof(struct file_operations));
         dvbdev->fops->owner = adap->module;
 
         list_add_tail (&dvbdev->list_head, &adap->device_list);
@@ -251,6 +263,7 @@ void dvb_unregister_device(struct dvb_device *dvbdev)
                                         dvbdev->type, dvbdev->id)));
 
         list_del (&dvbdev->list_head);
+        kfree (dvbdev->fops);
         kfree (dvbdev);
 }
 EXPORT_SYMBOL(dvb_unregister_device);