Re: [PATCH 10/19] firmware: turris-mox-rwtm: Simplify driver kobject code

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

[-- Attachment #1: Type: text/plain, Size: 3386 bytes --]

On Wed, 12 Jun 2024, Marek Behún wrote:

> Drop the mox_kobject wrapper that needs to be allocated, instead put the
> kobject directly into the driver private structure. This allows us to
> drop one kzalloc() call.
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>
> ---
>  drivers/firmware/turris-mox-rwtm.c | 36 ++++++++----------------------
>  1 file changed, 9 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/firmware/turris-mox-rwtm.c b/drivers/firmware/turris-mox-rwtm.c
> index 6d1e0b1dd2b4..84ec72575c4d 100644
> --- a/drivers/firmware/turris-mox-rwtm.c
> +++ b/drivers/firmware/turris-mox-rwtm.c
> @@ -21,7 +21,6 @@
>  #include <linux/module.h>
>  #include <linux/mutex.h>
>  #include <linux/platform_device.h>
> -#include <linux/slab.h>
>  #include <linux/sysfs.h>
>  #include <linux/types.h>
>  
> @@ -58,13 +57,11 @@ enum mbox_cmd {
>  	MBOX_CMD_OTP_WRITE	= 8,
>  };
>  
> -struct mox_kobject;
> -
>  struct mox_rwtm {
>  	struct device *dev;
>  	struct mbox_client mbox_client;
>  	struct mbox_chan *mbox;
> -	struct mox_kobject *kobj;
> +	struct kobject kobj;
>  	struct hwrng hwrng;
>  
>  	struct armada_37xx_rwtm_rx_msg reply;
> @@ -97,19 +94,9 @@ struct mox_rwtm {
>  #endif
>  };
>  
> -struct mox_kobject {
> -	struct kobject kobj;
> -	struct mox_rwtm *rwtm;
> -};
> -
> -static inline struct kobject *rwtm_to_kobj(struct mox_rwtm *rwtm)
> -{
> -	return &rwtm->kobj->kobj;
> -}
> -
>  static inline struct mox_rwtm *to_rwtm(struct kobject *kobj)
>  {
> -	return container_of(kobj, struct mox_kobject, kobj)->rwtm;
> +	return container_of(kobj, struct mox_rwtm, kobj);
>  }
>  
>  #define MOX_ATTR_RO(name, format, cat)				\
> @@ -142,9 +129,8 @@ static struct attribute *mox_rwtm_attrs[] = {
>  };
>  ATTRIBUTE_GROUPS(mox_rwtm);
>  
> -static void mox_kobj_release(struct kobject *kobj)
> +static void mox_kobj_release(struct kobject *)
>  {
> -	kfree(to_rwtm(kobj)->kobj);
>  }

Is empty .release necessary at all? I found some kobj_type structs without 
.release so I'd expect it to be unnecessary.

-- 
 i.

>  static const struct kobj_type mox_kobj_ktype = {
> @@ -155,18 +141,14 @@ static const struct kobj_type mox_kobj_ktype = {
>  
>  static int mox_kobj_create(struct mox_rwtm *rwtm)
>  {
> -	rwtm->kobj = kzalloc(sizeof(*rwtm->kobj), GFP_KERNEL);
> -	if (!rwtm->kobj)
> -		return -ENOMEM;
> +	struct kobject *kobj = &rwtm->kobj;
>  
> -	kobject_init(rwtm_to_kobj(rwtm), &mox_kobj_ktype);
> -	if (kobject_add(rwtm_to_kobj(rwtm), firmware_kobj, "turris-mox-rwtm")) {
> -		kobject_put(rwtm_to_kobj(rwtm));
> +	kobject_init(kobj, &mox_kobj_ktype);
> +	if (kobject_add(kobj, firmware_kobj, "turris-mox-rwtm")) {
> +		kobject_put(kobj);
>  		return -ENXIO;
>  	}
>  
> -	rwtm->kobj->rwtm = rwtm;
> -
>  	return 0;
>  }
>  
> @@ -540,7 +522,7 @@ static int turris_mox_rwtm_probe(struct platform_device *pdev)
>  free_channel:
>  	mbox_free_channel(rwtm->mbox);
>  put_kobj:
> -	kobject_put(rwtm_to_kobj(rwtm));
> +	kobject_put(&rwtm->kobj);
>  	return ret;
>  }
>  
> @@ -548,7 +530,7 @@ static void turris_mox_rwtm_remove(struct platform_device *pdev)
>  {
>  	struct mox_rwtm *rwtm = platform_get_drvdata(pdev);
>  
> -	kobject_put(rwtm_to_kobj(rwtm));
> +	kobject_put(&rwtm->kobj);
>  	mbox_free_channel(rwtm->mbox);
>  }
>  
>