| Message ID | 20150309180409.GA24645@dtor-ws |
|---|---|
| State | New |
| Headers | show |
On Mon, Mar 9, 2015 at 7:04 PM, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > Even if bus is not hot-pluggable, the devices can be unbound from the > driver via sysfs, so we should not be using __exit annotations on > remove() methods. The only exception is drivers registered with > platform_driver_probe() which specifically disables sysfs bind/unbind > attributes. > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> I prefer to have this fixed by setting .suppress_bind_attrs = true in the struct device_driver .drv portion of the device driver, so the driver cannot be removed from sysfs. So platform_driver_probe() isn't really the only exception, there is a way to do the same supression on ordinary drivers if we know we won't fiddle with them from sysfs. Can you make a patch as per above (alternatively tell me how wrong I am...) Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 17, 2015 at 01:30:15PM +0100, Linus Walleij wrote: > On Mon, Mar 9, 2015 at 7:04 PM, Dmitry Torokhov > <dmitry.torokhov@gmail.com> wrote: > > > Even if bus is not hot-pluggable, the devices can be unbound from the > > driver via sysfs, so we should not be using __exit annotations on > > remove() methods. The only exception is drivers registered with > > platform_driver_probe() which specifically disables sysfs bind/unbind > > attributes. > > > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > > I prefer to have this fixed by setting > .suppress_bind_attrs = true > in the struct device_driver .drv portion of the device driver, > so the driver cannot be removed from sysfs. > > So platform_driver_probe() isn't really the only exception, > there is a way to do the same supression on ordinary drivers > if we know we won't fiddle with them from sysfs. Yes, you are right, setting suppress_bind_attrs will work too. > > Can you make a patch as per above (alternatively tell me > how wrong I am...) Unfortunately I won't be able to do that as I can't provide justification for such change (i.e. I do not know why you want to disable unbinding while still keeping the remove() implementation. Thanks.
On Wed, Mar 18, 2015 at 5:55 PM, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > On Tue, Mar 17, 2015 at 01:30:15PM +0100, Linus Walleij wrote: >> On Mon, Mar 9, 2015 at 7:04 PM, Dmitry Torokhov >> <dmitry.torokhov@gmail.com> wrote: >> >> > Even if bus is not hot-pluggable, the devices can be unbound from the >> > driver via sysfs, so we should not be using __exit annotations on >> > remove() methods. The only exception is drivers registered with >> > platform_driver_probe() which specifically disables sysfs bind/unbind >> > attributes. >> > >> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> >> >> I prefer to have this fixed by setting >> .suppress_bind_attrs = true >> in the struct device_driver .drv portion of the device driver, >> so the driver cannot be removed from sysfs. >> >> So platform_driver_probe() isn't really the only exception, >> there is a way to do the same supression on ordinary drivers >> if we know we won't fiddle with them from sysfs. > > Yes, you are right, setting suppress_bind_attrs will work too. > >> >> Can you make a patch as per above (alternatively tell me >> how wrong I am...) > > Unfortunately I won't be able to do that as I can't provide > justification for such change (i.e. I do not know why you want to > disable unbinding while still keeping the remove() implementation. You are right, I want a patch deleting the remove() implementation and setting the .suppress_bind_attrs = true at the same time. For a bool driver of this type (typically compiled in and probed at boot) that makes most sense to me. Well I guess there are a ton of drivers that should be done like that ... just wanna start somewhere. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Mar 25, 2015 at 04:32:13PM +0100, Linus Walleij wrote: > On Wed, Mar 18, 2015 at 5:55 PM, Dmitry Torokhov > <dmitry.torokhov@gmail.com> wrote: > > On Tue, Mar 17, 2015 at 01:30:15PM +0100, Linus Walleij wrote: > >> On Mon, Mar 9, 2015 at 7:04 PM, Dmitry Torokhov > >> <dmitry.torokhov@gmail.com> wrote: > >> > >> > Even if bus is not hot-pluggable, the devices can be unbound from the > >> > driver via sysfs, so we should not be using __exit annotations on > >> > remove() methods. The only exception is drivers registered with > >> > platform_driver_probe() which specifically disables sysfs bind/unbind > >> > attributes. > >> > > >> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > >> > >> I prefer to have this fixed by setting > >> .suppress_bind_attrs = true > >> in the struct device_driver .drv portion of the device driver, > >> so the driver cannot be removed from sysfs. > >> > >> So platform_driver_probe() isn't really the only exception, > >> there is a way to do the same supression on ordinary drivers > >> if we know we won't fiddle with them from sysfs. > > > > Yes, you are right, setting suppress_bind_attrs will work too. > > > >> > >> Can you make a patch as per above (alternatively tell me > >> how wrong I am...) > > > > Unfortunately I won't be able to do that as I can't provide > > justification for such change (i.e. I do not know why you want to > > disable unbinding while still keeping the remove() implementation. > > You are right, I want a patch deleting the remove() implementation > and setting the .suppress_bind_attrs = true at the same time. > > For a bool driver of this type (typically compiled in and probed > at boot) that makes most sense to me. Hmm, I do not think this is a good justification for disabling unbinding. However, as far as I can see, removing gpiochip will succeed even though there are users of gpios in the system and that might justify the change. But does this mean that we give up on making gpiochip clean up properly and we should schedule gpiochip_remove() and the rest of gpio cleanup infrastructure for removal and declare that gpio drivers can not ever be made modules? Seems like wrong direction to move to... Thanks.
On Wed, Mar 25, 2015 at 6:14 PM, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > On Wed, Mar 25, 2015 at 04:32:13PM +0100, Linus Walleij wrote: >> For a bool driver of this type (typically compiled in and probed >> at boot) that makes most sense to me. > > Hmm, I do not think this is a good justification for disabling > unbinding. However, as far as I can see, removing gpiochip will succeed > even though there are users of gpios in the system and that might > justify the change. But does this mean that we give up on making > gpiochip clean up properly and we should schedule gpiochip_remove() and > the rest of gpio cleanup infrastructure for removal and declare that > gpio drivers can not ever be made modules? No. Johan Hovold is looking into use cases for GPIO chips that come and go, think GPIO on USB. These obviously need remove() semantics. What I'm thinking is that the SoC-embedded GPIO controllers (I don't know how many these are) should probably be bool in Kconfig and also patched not to have remove() functions and drop the sysfs attribs for unbinding. But now I think I'll just apply the patch anyways because it sure does not make a difference wrt to the bigger problem, so I'm just bitching around about details and thinking aloud, sorry.. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Mar 9, 2015 at 7:04 PM, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > Even if bus is not hot-pluggable, the devices can be unbound from the > driver via sysfs, so we should not be using __exit annotations on > remove() methods. The only exception is drivers registered with > platform_driver_probe() which specifically disables sysfs bind/unbind > attributes. > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Patch applied. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpio-tb10x.c b/drivers/gpio/gpio-tb10x.c index 62ab9f4..46b8961 100644 --- a/drivers/gpio/gpio-tb10x.c +++ b/drivers/gpio/gpio-tb10x.c @@ -283,7 +283,7 @@ fail_ioremap: return ret; } -static int __exit tb10x_gpio_remove(struct platform_device *pdev) +static int tb10x_gpio_remove(struct platform_device *pdev) { struct tb10x_gpio *tb10x_gpio = platform_get_drvdata(pdev);
Even if bus is not hot-pluggable, the devices can be unbound from the driver via sysfs, so we should not be using __exit annotations on remove() methods. The only exception is drivers registered with platform_driver_probe() which specifically disables sysfs bind/unbind attributes. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> --- drivers/gpio/gpio-tb10x.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)