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Message-ID: <cf5b2696-d7ca-40fc-856a-52f352cd270c@ieee.org>
Date: Sat, 24 Feb 2024 09:43:30 -0600
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MIME-Version: 1.0
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Subject: Re: [PATCH] greybus: constify the struct device_type usage
Content-Language: en-US
To: "Ricardo B. Marliere" <ricardo@marliere.net>,
 Johan Hovold <johan@kernel.org>, Alex Elder <elder@kernel.org>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: greybus-dev@lists.linaro.org, linux-kernel@vger.kernel.org
References: <20240219-device_cleanup-greybus-v1-1-babb3f65e8cc@marliere.net>
From: Alex Elder <elder@ieee.org>
In-Reply-To: <20240219-device_cleanup-greybus-v1-1-babb3f65e8cc@marliere.net>
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On 2/19/24 6:40 AM, Ricardo B. Marliere wrote:
> Since commit aed65af1cc2f ("drivers: make device_type const"), the driver
> core can properly handle constant struct device_type. Move the
> greybus_hd_type, greybus_module_type, greybus_interface_type,
> greybus_control_type, greybus_bundle_type and greybus_svc_type variables to
> be constant structures as well, placing it into read-only memory which can
> not be modified at runtime.
> 
> Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>

This looks good to me.  Assuming it compiles cleanly:

Reviewed-by: Alex Elder <elder@linaro.org>

On another subject:

Johan might disagree, but I think it would be nice to make
the definitions of the Greybus device types as static (private)
and make the is_gb_host_device() etc. functions real functions
rather than static inlines in <linux/greybus.h>.

It turns out that all of the is_gb_*() functions are called only
from drivers/greybus/core.c; they could all be moved there rather
than advertising them in <linux/greybus.h>.

					-Alex


> ---
>   drivers/greybus/bundle.c    |  2 +-
>   drivers/greybus/control.c   |  2 +-
>   drivers/greybus/hd.c        |  2 +-
>   drivers/greybus/interface.c |  2 +-
>   drivers/greybus/module.c    |  2 +-
>   drivers/greybus/svc.c       |  2 +-
>   include/linux/greybus.h     | 12 ++++++------
>   7 files changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/greybus/bundle.c b/drivers/greybus/bundle.c
> index 84660729538b..a6e1cca06172 100644
> --- a/drivers/greybus/bundle.c
> +++ b/drivers/greybus/bundle.c
> @@ -166,7 +166,7 @@ static const struct dev_pm_ops gb_bundle_pm_ops = {
>   	SET_RUNTIME_PM_OPS(gb_bundle_suspend, gb_bundle_resume, gb_bundle_idle)
>   };
>   
> -struct device_type greybus_bundle_type = {
> +const struct device_type greybus_bundle_type = {
>   	.name =		"greybus_bundle",
>   	.release =	gb_bundle_release,
>   	.pm =		&gb_bundle_pm_ops,
> diff --git a/drivers/greybus/control.c b/drivers/greybus/control.c
> index 359a25841973..b5cf49d09df2 100644
> --- a/drivers/greybus/control.c
> +++ b/drivers/greybus/control.c
> @@ -436,7 +436,7 @@ static void gb_control_release(struct device *dev)
>   	kfree(control);
>   }
>   
> -struct device_type greybus_control_type = {
> +const struct device_type greybus_control_type = {
>   	.name =		"greybus_control",
>   	.release =	gb_control_release,
>   };
> diff --git a/drivers/greybus/hd.c b/drivers/greybus/hd.c
> index 72b21bf2d7d3..e2f3496bddc3 100644
> --- a/drivers/greybus/hd.c
> +++ b/drivers/greybus/hd.c
> @@ -116,7 +116,7 @@ static void gb_hd_release(struct device *dev)
>   	kfree(hd);
>   }
>   
> -struct device_type greybus_hd_type = {
> +const struct device_type greybus_hd_type = {
>   	.name		= "greybus_host_device",
>   	.release	= gb_hd_release,
>   };
> diff --git a/drivers/greybus/interface.c b/drivers/greybus/interface.c
> index 9ec949a438ef..a88dc701289c 100644
> --- a/drivers/greybus/interface.c
> +++ b/drivers/greybus/interface.c
> @@ -765,7 +765,7 @@ static const struct dev_pm_ops gb_interface_pm_ops = {
>   			   gb_interface_runtime_idle)
>   };
>   
> -struct device_type greybus_interface_type = {
> +const struct device_type greybus_interface_type = {
>   	.name =		"greybus_interface",
>   	.release =	gb_interface_release,
>   	.pm =		&gb_interface_pm_ops,
> diff --git a/drivers/greybus/module.c b/drivers/greybus/module.c
> index 36f77f9e1d74..7f7153a1dd60 100644
> --- a/drivers/greybus/module.c
> +++ b/drivers/greybus/module.c
> @@ -81,7 +81,7 @@ static void gb_module_release(struct device *dev)
>   	kfree(module);
>   }
>   
> -struct device_type greybus_module_type = {
> +const struct device_type greybus_module_type = {
>   	.name		= "greybus_module",
>   	.release	= gb_module_release,
>   };
> diff --git a/drivers/greybus/svc.c b/drivers/greybus/svc.c
> index 0d7e749174a4..4256467fcd35 100644
> --- a/drivers/greybus/svc.c
> +++ b/drivers/greybus/svc.c
> @@ -1305,7 +1305,7 @@ static void gb_svc_release(struct device *dev)
>   	kfree(svc);
>   }
>   
> -struct device_type greybus_svc_type = {
> +const struct device_type greybus_svc_type = {
>   	.name		= "greybus_svc",
>   	.release	= gb_svc_release,
>   };
> diff --git a/include/linux/greybus.h b/include/linux/greybus.h
> index 18c0fb958b74..5f9791fae3c0 100644
> --- a/include/linux/greybus.h
> +++ b/include/linux/greybus.h
> @@ -106,12 +106,12 @@ struct dentry *gb_debugfs_get(void);
>   
>   extern struct bus_type greybus_bus_type;
>   
> -extern struct device_type greybus_hd_type;
> -extern struct device_type greybus_module_type;
> -extern struct device_type greybus_interface_type;
> -extern struct device_type greybus_control_type;
> -extern struct device_type greybus_bundle_type;
> -extern struct device_type greybus_svc_type;
> +extern const struct device_type greybus_hd_type;
> +extern const struct device_type greybus_module_type;
> +extern const struct device_type greybus_interface_type;
> +extern const struct device_type greybus_control_type;
> +extern const struct device_type greybus_bundle_type;
> +extern const struct device_type greybus_svc_type;
>   
>   static inline int is_gb_host_device(const struct device *dev)
>   {
> 
> ---
> base-commit: b401b621758e46812da61fa58a67c3fd8d91de0d
> change-id: 20240219-device_cleanup-greybus-c97c1ef52458
> 
> Best regards,