On wo, 2015-12-02 at 18:48 -0500, Peter Hurley wrote:

On 11/30/2015 01:01 PM, Paul Bolle wrote:

quoted

Should (something like) this go into stable too?

Definitely for stable since it has a userspace triggerable component.

Thanks, will do.

quoted

--- a/drivers/isdn/gigaset/ser-gigaset.c
+++ b/drivers/isdn/gigaset/ser-gigaset.c

@@ -42,8 +42,9 @@ MODULE_PARM_DESC(cidmode, "stay in CID mode when

idle");
 
 static struct gigaset_driver *driver;
 
+static struct platform_device pdev;
+
 struct ser_cardstate {
-	struct platform_device	dev;
 	struct tty_struct	*tty;
 	atomic_t		refcnt;
 	struct completion	dead_cmp;

@@ -370,8 +371,8 @@ static void gigaset_freecshw(struct cardstate

*cs)
 	tasklet_kill(&cs->write_tasklet);
 	if (!cs->hw.ser)
 		return;
-	dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
-	platform_device_unregister(&cs->hw.ser->dev);
+	dev_set_drvdata(&pdev.dev, NULL);
+	platform_device_unregister(&pdev);
 	kfree(cs->hw.ser);

Tilman,

Is there a 1:1 correspondence and lifetime for the embedded platform
device and it's containing memory?

(Haven't heard from Tilman, so I'll give this a try.)

That containing memory is a struct ser_cardstate. And currently
instances of struct _ser_cardstate are malloced and freed in routines
that also call platform_device_register() and
platform_device_unregister(). So yes, I think there's a 1:1
correspondence.

I ask because the typical approach for device teardown is to put the
kfree() in the release method;

(Side note: the (struct device) release method of this driver 
-gigaset_device_release() - is actually a nop. It only frees device
->platform_data and platform_device->resource, but neither are actually
used: they remain NULL through their entire life.)

 naturally, that won't work if there
is some other lifetime issue.

I'm not sure I follow what you mean here. Could you point me at a driver
that uses that approach, so that I can have a look at it?

Thanks,


Paul Bolle