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authorJonathan Nieder <jrnieder@gmail.com>2011-05-01 09:30:46 (GMT)
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-05-20 12:29:40 (GMT)
commit579b2b45120fa33f750cd65150d6d8995938750b (patch)
tree8338da6519c62b3d40e486df85acf5eacce6c137
parent344d6c6ba6ba5c4fede2f07adbd26d53109a2dd8 (diff)
downloadlinux-fsl-qoriq-579b2b45120fa33f750cd65150d6d8995938750b.tar.xz
[media] cx88: gracefully reject attempts to use unregistered cx88-blackbird driver
It should not be possible to enter mpeg_open and acquire core->lock without the blackbird driver being registered, so just error out if it is not. This makes the code more readable and should prevent the bug fixed by the patch "hold device lock during sub-driver initialization" from resurfacing again. Similarly, if we enter mpeg_release and acquire core->lock then either the blackbird driver is registered (since open files keep it loaded) or the sysadmin forced the driver's removal. In the latter case the state will be inconsistent and this is worth a loud warning. 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>
-rw-r--r--drivers/media/video/cx88/cx88-blackbird.c25
1 files changed, 14 insertions, 11 deletions
diff --git a/drivers/media/video/cx88/cx88-blackbird.c b/drivers/media/video/cx88/cx88-blackbird.c
index f637d34..fa8e347 100644
--- a/drivers/media/video/cx88/cx88-blackbird.c
+++ b/drivers/media/video/cx88/cx88-blackbird.c
@@ -1060,18 +1060,21 @@ static int mpeg_open(struct file *file)
/* Make sure we can acquire the hardware */
drv = cx8802_get_driver(dev, CX88_MPEG_BLACKBIRD);
- if (drv) {
- err = drv->request_acquire(drv);
- if(err != 0) {
- dprintk(1,"%s: Unable to acquire hardware, %d\n", __func__, err);
- mutex_unlock(&dev->core->lock);
- return err;
- }
+ if (!drv) {
+ dprintk(1, "%s: blackbird driver is not loaded\n", __func__);
+ mutex_unlock(&dev->core->lock);
+ return -ENODEV;
+ }
+
+ err = drv->request_acquire(drv);
+ if (err != 0) {
+ dprintk(1,"%s: Unable to acquire hardware, %d\n", __func__, err);
+ mutex_unlock(&dev->core->lock);
+ return err;
}
if (!atomic_read(&dev->core->mpeg_users) && blackbird_initialize_codec(dev) < 0) {
- if (drv)
- drv->request_release(drv);
+ drv->request_release(drv);
mutex_unlock(&dev->core->lock);
return -EINVAL;
}
@@ -1080,8 +1083,7 @@ static int mpeg_open(struct file *file)
/* allocate + initialize per filehandle data */
fh = kzalloc(sizeof(*fh),GFP_KERNEL);
if (NULL == fh) {
- if (drv)
- drv->request_release(drv);
+ drv->request_release(drv);
mutex_unlock(&dev->core->lock);
return -ENOMEM;
}
@@ -1125,6 +1127,7 @@ static int mpeg_release(struct file *file)
/* Make sure we release the hardware */
drv = cx8802_get_driver(dev, CX88_MPEG_BLACKBIRD);
+ WARN_ON(!drv);
if (drv)
drv->request_release(drv);