On 15/02/17 06:05, Cheah Kok Cheong wrote:
On Mon, Feb 13, 2017 at 11:14:14AM +0000, Ian Abbott wrote:
On 11/02/17 10:37, Cheah Kok Cheong wrote:
[snip]
+static void __exit comedi_test_exit(void)
+{
+ comedi_auto_unconfig(ctdev);
+
+ device_destroy(ctcls, MKDEV(0, 0));
+
+ class_destroy(ctcls);
If the driver init returned successfully, but failed to set-up the
auto-configured device, the device and class will not exist at this point,
so those three calls need to go in an 'if' statement. Perhaps you could use
'if (ctcls) {', and set 'ctcls = NULL;' after calling
'class_destroy(ctcls);' in the init function.
Apart from that, it looks fine.
Thanks for pointing out those two pointers have to be "NULL" if
auto-configuration fails.
Please review below snippet.
Sorry for the inconvenience caused.
[ Snip ]
static int __init comedi_test_init(void)
{
int ret;
ret = comedi_driver_register(&waveform_driver);
if (ret) {
pr_err("comedi_test: unable to register driver\n");
return ret;
}
if (!config_mode) {
ctcls = class_create(THIS_MODULE, CLASS_NAME);
if (IS_ERR(ctcls)) {
pr_warn("comedi_test: unable to create class\n");
goto clean3;
}
ctdev = device_create(ctcls, NULL, MKDEV(0, 0), NULL, DEV_NAME);
if (IS_ERR(ctdev)) {
pr_warn("comedi_test: unable to create device\n");
goto clean2;
}
ret = comedi_auto_config(ctdev, &waveform_driver, 0);
if (ret) {
pr_warn("comedi_test: unable to auto-configure device\n");
goto clean;
}
}
return 0;
clean:
device_destroy(ctcls, MKDEV(0, 0));
clean2:
class_destroy(ctcls);
ctdev = NULL;
clean3:
ctcls = NULL;
return 0;
}
module_init(comedi_test_init);
static void __exit comedi_test_exit(void)
{
if (ctdev)
comedi_auto_unconfig(ctdev);
if (ctcls) {
device_destroy(ctcls, MKDEV(0, 0));
class_destroy(ctcls);
}
comedi_driver_unregister(&waveform_driver);
}
module_exit(comedi_test_exit);
[ Snip ]
Thks.
Brgds,
CheahKC
Yes, that looks fine.
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Web: http://www.mev.co.uk/ )=-
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