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authorJonathan Nieder <jrnieder@gmail.com>2011-05-01 13:30:14 +0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-05-20 16:29:38 +0400
commit344d6c6ba6ba5c4fede2f07adbd26d53109a2dd8 (patch)
treee76f78428ccde8e7c294f23ce128728ce0afb3d6 /drivers/media/video/cx88
parent1d6213ab995c61f7d1d81cf6cf876acf15d6e714 (diff)
downloadlinux-344d6c6ba6ba5c4fede2f07adbd26d53109a2dd8.tar.xz
[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>
Diffstat (limited to 'drivers/media/video/cx88')
-rw-r--r--drivers/media/video/cx88/cx88-mpeg.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/drivers/media/video/cx88/cx88-mpeg.c b/drivers/media/video/cx88/cx88-mpeg.c
index 455290011d4e..1a7b983f8297 100644
--- a/drivers/media/video/cx88/cx88-mpeg.c
+++ b/drivers/media/video/cx88/cx88-mpeg.c
@@ -78,6 +78,7 @@ static void flush_request_modules(struct cx8802_dev *dev)
static LIST_HEAD(cx8802_devlist);
+static DEFINE_MUTEX(cx8802_mutex);
/* ------------------------------------------------------------------ */
static int cx8802_start_dma(struct cx8802_dev *dev,
@@ -689,6 +690,8 @@ int cx8802_register_driver(struct cx8802_driver *drv)
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 @@ int cx8802_register_driver(struct cx8802_driver *drv)
/* 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 @@ int cx8802_register_driver(struct cx8802_driver *drv)
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 @@ int cx8802_unregister_driver(struct cx8802_driver *drv)
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 @@ int cx8802_unregister_driver(struct cx8802_driver *drv)
mutex_unlock(&dev->core->lock);
}
+ mutex_unlock(&cx8802_mutex);
+
return err;
}
@@ -799,7 +811,9 @@ static int __devinit cx8802_probe(struct pci_dev *pci_dev,
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);