On Fri, 19 Mar 2004 16:14:56 +0100
Oliver Neukum <[EMAIL PROTECTED]> wrote:
> open() is (for char devices) still called under BKL, so this is
> just uselessly eating cycles. And, more importantly, locking
> is not thought through. It is correct by accident currently.
I wouldn't touch it before a replacement is done. I vote for
making the usblp->sem static and using that instead.
What do you think about the attached patch?
-- Pete
--- linux-2.6.5-rc1/drivers/usb/class/usblp.c 2004-03-14 15:44:28.000000000 -0800
+++ linux-2.6.5-rc1-wacom/drivers/usb/class/usblp.c 2004-03-19 09:51:44.000000000
-0800
@@ -219,6 +219,8 @@
/* forward reference to make our lives easier */
extern struct usb_driver usblp_driver;
+static struct semaphore usblp_sem; /* locks the existence of usblp's. */
+
/*
* Functions for usblp control messages.
*/
@@ -329,7 +331,7 @@
if (minor < 0)
return -ENODEV;
- lock_kernel();
+ down (&usblp_sem);
retval = -ENODEV;
intf = usb_find_interface(&usblp_driver, minor);
@@ -375,7 +377,7 @@
}
}
out:
- unlock_kernel();
+ up (&usblp_sem);
return retval;
}
@@ -405,13 +407,13 @@
{
struct usblp *usblp = file->private_data;
- down (&usblp->sem);
+ down (&usblp_sem);
usblp->used = 0;
if (usblp->present) {
usblp_unlink_urbs(usblp);
- up(&usblp->sem);
} else /* finish cleanup from disconnect */
usblp_cleanup (usblp);
+ up (&usblp_sem);
return 0;
}
@@ -1123,18 +1125,17 @@
BUG ();
}
+ down (&usblp_sem);
down (&usblp->sem);
- lock_kernel();
usblp->present = 0;
usb_set_intfdata (intf, NULL);
usblp_unlink_urbs(usblp);
+ up (&usblp->sem);
if (!usblp->used)
usblp_cleanup (usblp);
- else /* cleanup later, on release */
- up (&usblp->sem);
- unlock_kernel();
+ up (&usblp_sem);
}
static struct usb_device_id usblp_ids [] = {
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