Re: [linux-usb-devel] [PATCH] USB speedtouch: don't open a connection if no firmware

[Duncan Sands]

> > Hi Greg, I'm waiting on the fixes to the ATM layer (coming soon to a
> > kernel near you).
>
> Ah, ok, that makes sense.
>
> > As for the position of MOD_INC_USE_COUNT, did you ever hear
> > of anyone getting bitten by a race like this?  If it makes you feel
> > better, I will move it up, probably just before I take the semaphore
> > (since that is the first place we can sleep).  I will do it tomorrow, OK?
>
> Yes, it needs to be before any function that can sleep.  I'll hold off
> applying this patch then.

How about this one instead.  MOD_INC_USE_COUNT is placed before I call
any functions that can sleep.  Let's just hope that the call to me doesn't
come after some sleeping in the higher layers...

Duncan.

--- redux-2.5/drivers/usb/misc/speedtch.c	2003-04-08 08:49:33.000000000 +0200
+++ bollux-2.5/drivers/usb/misc/speedtch.c	2003-04-09 10:08:27.000000000 +0200
@@ -933,15 +933,24 @@
 	if (vcc->qos.aal != ATM_AAL5)
 		return -EINVAL;
 
+	if (!instance->firmware_loaded) {
+		dbg ("firmware not loaded!");
+		return -EAGAIN;
+	}
+
+	MOD_INC_USE_COUNT;
+
 	down (&instance->serialize); /* vs self, udsl_atm_close */
 
 	if (udsl_find_vcc (instance, vpi, vci)) {
 		up (&instance->serialize);
+		MOD_DEC_USE_COUNT;
 		return -EADDRINUSE;
 	}
 
 	if (!(new = kmalloc (sizeof (struct udsl_vcc_data), GFP_KERNEL))) {
 		up (&instance->serialize);
+		MOD_DEC_USE_COUNT;
 		return -ENOMEM;
 	}
 
@@ -967,10 +976,7 @@
 
 	dbg ("Allocated new SARLib vcc 0x%p with vpi %d vci %d", new, vpi, vci);
 
-	MOD_INC_USE_COUNT;
-
-	if (instance->firmware_loaded)
-		udsl_fire_receivers (instance);
+	udsl_fire_receivers (instance);
 
 	dbg ("udsl_atm_open successful");
 
@@ -1041,6 +1047,7 @@
 		int ret;
 
 		if ((ret = usb_set_interface (instance->usb_dev, 1, 1)) < 0) {
+			dbg ("usb_set_interface returned %d!", ret);
 			up (&instance->serialize);
 			return ret;
 		}