USB testing driver: convert semaphore dev->sem to the mutex API
Signed-off-by: Matthias Kaehlcke <[email protected]>
--
diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index ea31621..57260ab 100644
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -6,6 +6,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/scatterlist.h>
+#include <linux/mutex.h>
#include <linux/usb.h>
@@ -64,7 +65,7 @@ struct usbtest_dev {
int in_iso_pipe;
int out_iso_pipe;
struct usb_endpoint_descriptor *iso_in, *iso_out;
- struct semaphore sem;
+ struct mutex lock;
#define TBUF_SIZE 256
u8 *buf;
@@ -1558,11 +1559,11 @@ usbtest_ioctl (struct usb_interface *intf, unsigned int code, void *buf)
|| param->sglen < 0 || param->vary < 0)
return -EINVAL;
- if (down_interruptible (&dev->sem))
+ if (mutex_lock_interruptible(&dev->lock))
return -ERESTARTSYS;
if (intf->dev.power.power_state.event != PM_EVENT_ON) {
- up (&dev->sem);
+ mutex_unlock(&dev->lock);
return -EHOSTUNREACH;
}
@@ -1574,7 +1575,7 @@ usbtest_ioctl (struct usb_interface *intf, unsigned int code, void *buf)
int res;
if (intf->altsetting->desc.bInterfaceNumber) {
- up (&dev->sem);
+ mutex_unlock(&dev->lock);
return -ENODEV;
}
res = set_altsetting (dev, dev->info->alt);
@@ -1582,7 +1583,7 @@ usbtest_ioctl (struct usb_interface *intf, unsigned int code, void *buf)
dev_err (&intf->dev,
"set altsetting to %d failed, %d\n",
dev->info->alt, res);
- up (&dev->sem);
+ mutex_unlock(&dev->lock);
return res;
}
}
@@ -1855,7 +1856,7 @@ usbtest_ioctl (struct usb_interface *intf, unsigned int code, void *buf)
param->duration.tv_usec += 1000 * 1000;
param->duration.tv_sec -= 1;
}
- up (&dev->sem);
+ mutex_unlock(&dev->lock);
return retval;
}
@@ -1905,7 +1906,7 @@ usbtest_probe (struct usb_interface *intf, const struct usb_device_id *id)
return -ENOMEM;
info = (struct usbtest_info *) id->driver_info;
dev->info = info;
- init_MUTEX (&dev->sem);
+ mutex_init(&dev->lock);
dev->intf = intf;
@@ -1990,7 +1991,7 @@ static void usbtest_disconnect (struct usb_interface *intf)
{
struct usbtest_dev *dev = usb_get_intfdata (intf);
- down (&dev->sem);
+ mutex_lock(&dev->lock);
usb_set_intfdata (intf, NULL);
dev_dbg (&intf->dev, "disconnect\n");
--
Matthias Kaehlcke
Linux Application Developer
Barcelona
Tant qu'il y aura sur terre des hommes pour qui existe un concept
d' 'honneur national', la menace d'une nouvelle guerre subsistera
(B. Traven)
.''`.
using free software / Debian GNU/Linux | http://debian.org : :' :
`. `'`
gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `-
On Tue, 2007-12-04 at 17:55 +0100, Matthias Kaehlcke wrote:
> @@ -1990,7 +1991,7 @@ static void usbtest_disconnect (struct
> usb_interface *intf)
> {
> struct usbtest_dev *dev = usb_get_intfdata (intf);
>
> - down (&dev->sem);
> + mutex_lock(&dev->lock);
>
> usb_set_intfdata (intf, NULL);
> dev_dbg (&intf->dev, "disconnect\n");
This looks like a bit of an anomaly.. The code that isn't shown above is
the "kfree(dev)" .. So this isn't legal since it's freeing a locked
mutex. Here's a excerpt from the comment above mutex_lock(),
* The mutex must later on be released by the same task that
* acquired it. Recursive locking is not allowed. The task
* may not exit without first unlocking the mutex. Also, kernel
* memory where the mutex resides mutex must not be freed with
* the mutex still locked. The mutex must first be initialized
* (or statically defined) before it can be locked. memset()-ing
* the mutex to 0 is not allowed.
Daniel
El Tue, Dec 04, 2007 at 11:09:02AM -0800 Daniel Walker ha dit:
> On Tue, 2007-12-04 at 17:55 +0100, Matthias Kaehlcke wrote:
> > @@ -1990,7 +1991,7 @@ static void usbtest_disconnect (struct
> > usb_interface *intf)
> > {
> > struct usbtest_dev *dev = usb_get_intfdata (intf);
> >
> > - down (&dev->sem);
> > + mutex_lock(&dev->lock);
> >
> > usb_set_intfdata (intf, NULL);
> > dev_dbg (&intf->dev, "disconnect\n");
>
> This looks like a bit of an anomaly.. The code that isn't shown above is
> the "kfree(dev)" .. So this isn't legal since it's freeing a locked
> mutex. Here's a excerpt from the comment above mutex_lock(),
>
> * The mutex must later on be released by the same task that
> * acquired it. Recursive locking is not allowed. The task
> * may not exit without first unlocking the mutex. Also, kernel
> * memory where the mutex resides mutex must not be freed with
> * the mutex still locked. The mutex must first be initialized
> * (or statically defined) before it can be locked. memset()-ing
> * the mutex to 0 is not allowed.
you're absolutely right that freeing a locked mutex isn't a good idea
thanks for pointing it out!
--
Matthias Kaehlcke
Linux System Developer
Barcelona
Don't walk behind me, I may not lead
Don't walk in front of me, I may not follow
Just walk beside me and be my friend
(Albert Camus)
.''`.
using free software / Debian GNU/Linux | http://debian.org : :' :
`. `'`
gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `-