[media] cx88: protect cx8802_devlist with a mutex
Add and use a mutex to protect the cx88-mpeg device list. Previously
the BKL prevented races.
Based on work by Ben Hutchings <ben@decadent.org.uk>.
Tested-by: Andi Huber <hobrom@gmx.at>
Tested-by: Marlon de Boer <marlon@hyves.nl>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx88/cx88-mpeg.c b/drivers/media/video/cx88/cx88-mpeg.c
index 4552900..1a7b983 100644
--- a/drivers/media/video/cx88/cx88-mpeg.c
+++ b/drivers/media/video/cx88/cx88-mpeg.c
@@ -78,6 +78,7 @@
static LIST_HEAD(cx8802_devlist);
+static DEFINE_MUTEX(cx8802_mutex);
/* ------------------------------------------------------------------ */
static int cx8802_start_dma(struct cx8802_dev *dev,
@@ -689,6 +690,8 @@
return err;
}
+ mutex_lock(&cx8802_mutex);
+
list_for_each_entry(dev, &cx8802_devlist, devlist) {
printk(KERN_INFO
"%s/2: subsystem: %04x:%04x, board: %s [card=%d]\n",
@@ -698,8 +701,10 @@
/* Bring up a new struct for each driver instance */
driver = kzalloc(sizeof(*drv),GFP_KERNEL);
- if (driver == NULL)
- return -ENOMEM;
+ if (driver == NULL) {
+ err = -ENOMEM;
+ goto out;
+ }
/* Snapshot of the driver registration data */
drv->core = dev->core;
@@ -722,7 +727,10 @@
mutex_unlock(&drv->core->lock);
}
- return i ? 0 : -ENODEV;
+ err = i ? 0 : -ENODEV;
+out:
+ mutex_unlock(&cx8802_mutex);
+ return err;
}
int cx8802_unregister_driver(struct cx8802_driver *drv)
@@ -736,6 +744,8 @@
drv->type_id == CX88_MPEG_DVB ? "dvb" : "blackbird",
drv->hw_access == CX8802_DRVCTL_SHARED ? "shared" : "exclusive");
+ mutex_lock(&cx8802_mutex);
+
list_for_each_entry(dev, &cx8802_devlist, devlist) {
printk(KERN_INFO
"%s/2: subsystem: %04x:%04x, board: %s [card=%d]\n",
@@ -762,6 +772,8 @@
mutex_unlock(&dev->core->lock);
}
+ mutex_unlock(&cx8802_mutex);
+
return err;
}
@@ -799,7 +811,9 @@
goto fail_free;
INIT_LIST_HEAD(&dev->drvlist);
+ mutex_lock(&cx8802_mutex);
list_add_tail(&dev->devlist,&cx8802_devlist);
+ mutex_unlock(&cx8802_mutex);
/* now autoload cx88-dvb or cx88-blackbird */
request_modules(dev);