Re: [PATCH 5/7] CAN: Add virtual CAN netdevice driver

Arnaldo Carvalho de Melo [off-list ref] writes:

quoted

+#ifdef CONFIG_CAN_DEBUG_DEVICES
+static int debug;
+module_param(debug, int, S_IRUGO);
+#endif

Can debug be a boolean? Like its counterpart on DCCP:

debug used to a bit mask, like it still is in core.h.  You can see
this in the test

        debug & 1 ? ... : ...

below.  Only the test for bit 0 is left, so we could change it to bool.

net/dccp/proto.c:

module_param(dccp_debug, bool, 0444);

Where we also use a namespace prefix, for those of us who use ctags or
cscope.

I think ctags should be able to handle multiple identical static
symbols.  Isn't it?  I find it somewhat clumsy to write

        modprobe vcan vcan_debug=1

I think it would be nice to change the module_param() macro so that
you can name the module argument and the corresponding variable
independently, like

        module_param(can_debug, "debug", bool, 0444);

OK, forget that last paragraph.  I've looked at the definition of
module_param() and have seen that we have module_param_named().  I
think we should use that.

quoted

+
+/* To be moved to linux/can/dev.h */

Is this comment still valid? If so can this move happen now? If not I
think it would be better to stick a "FIXME: " just before it, no?

OK.

quoted

+static int echo; /* echo testing. Default: 0 (Off) */
+module_param(echo, int, S_IRUGO);
+MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");

echo also seems to be a boolean

ACK.

quoted

+static int vcan_open(struct net_device *dev)
+{
+	DBG("%s: interface up\n", dev->name);
+
+	netif_start_queue(dev);
+	return 0;
+}
+
+static int vcan_stop(struct net_device *dev)
+{
+	DBG("%s: interface down\n", dev->name);
+
+	netif_stop_queue(dev);
+	return 0;
+}

Thinking out loud: I guess these days we can try to reduce the clutter
on the source code for things like "hey, I entered function foo" using
simple systemtap scripts, that could even be shipped with the kernel
sources. Not something pressing right now, just a suggestion.

I've never heard of systemtap before.  I've ust looked at its overview
web page which sounds promising.  I think I'll check it out when time
permits...


urs