Re: [PATCH 3/5] driver core: make struct device_type.uevent() take a const *
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: 2022-11-23 13:33:02
Also in:
alsa-devel, linux-acpi, linux-block, linux-devicetree, linux-i2c, linux-i3c, linux-media, linux-serial, linux-usb, lkml, platform-driver-x86
Hi, On 11/23/22 13:25, Greg Kroah-Hartman wrote:
The uevent() callback in struct device_type should not be modifying the device that is passed into it, so mark it as a const * and propagate the function signature changes out into all relevant subsystems that use this callback.
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diff --git a/drivers/platform/surface/aggregator/bus.c b/drivers/platform/surface/aggregator/bus.c index de539938896e..407eb55050a6 100644 --- a/drivers/platform/surface/aggregator/bus.c +++ b/drivers/platform/surface/aggregator/bus.c@@ -35,9 +35,9 @@ static struct attribute *ssam_device_attrs[] = { }; ATTRIBUTE_GROUPS(ssam_device); -static int ssam_device_uevent(struct device *dev, struct kobj_uevent_env *env) +static int ssam_device_uevent(const struct device *dev, struct kobj_uevent_env *env) { - struct ssam_device *sdev = to_ssam_device(dev); + const struct ssam_device *sdev = to_ssam_device(dev); return add_uevent_var(env, "MODALIAS=ssam:d%02Xc%02Xt%02Xi%02Xf%02X", sdev->uid.domain, sdev->uid.category,
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--- a/include/linux/surface_aggregator/device.h +++ b/include/linux/surface_aggregator/device.h@@ -229,7 +229,7 @@ static inline bool is_ssam_device(struct device *d) * Return: Returns a pointer to the &struct ssam_device wrapping the given * device @d. */ -static inline struct ssam_device *to_ssam_device(struct device *d) +static inline struct ssam_device *to_ssam_device(const struct device *d) { return container_of(d, struct ssam_device, dev); }
I am slightly conflicted about this change as that now more or less implicitly drops the const. So I'm wondering if it wouldn't be better to either create a function specifically for const pointers or to just open-code it in the instance above. I guess we could also convert this to a macro. Then at least there wouldn't be an explicit and potentially misleading const-conversion indicated in the function signature. Regards, Max