On Mon, Feb 13, 2017 at 11:14:14AM +0000, Ian Abbott wrote:
> On 11/02/17 10:37, Cheah Kok Cheong wrote:
> >+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");
> >+ return ret;
> >+ }
> >+
> >+ 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);
> >+
> >+ return 0;
> >+}
> >+module_init(comedi_test_init);
> >+
> >+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
_______________________________________________
devel mailing list
de...@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
