[12/21,staging] tm6000: Add locking for USB transfers.
Commit Message
This commit introduces the usb_lock mutex to ensure that a USB request
always gets the proper response. While this is currently not really
necessary it will become important as there are more users.
---
drivers/staging/tm6000/tm6000-cards.c | 1 +
drivers/staging/tm6000/tm6000-core.c | 3 +++
drivers/staging/tm6000/tm6000.h | 1 +
3 files changed, 5 insertions(+), 0 deletions(-)
@@ -1174,6 +1174,7 @@ static int tm6000_usb_probe(struct usb_interface *interface,
return -ENOMEM;
}
spin_lock_init(&dev->slock);
+ mutex_init(&dev->usb_lock);
/* Increment usage count */
tm6000_devused |= 1<<nr;
@@ -39,6 +39,8 @@ int tm6000_read_write_usb(struct tm6000_core *dev, u8 req_type, u8 req,
unsigned int pipe;
u8 *data = NULL;
+ mutex_lock(&dev->usb_lock);
+
if (len)
data = kzalloc(len, GFP_KERNEL);
@@ -86,6 +88,7 @@ int tm6000_read_write_usb(struct tm6000_core *dev, u8 req_type, u8 req,
}
kfree(data);
+ mutex_unlock(&dev->usb_lock);
return ret;
}
@@ -245,6 +245,7 @@ struct tm6000_core {
/* locks */
struct mutex lock;
+ struct mutex usb_lock;
/* usb transfer */
struct usb_device *udev; /* the usb device */