linux-kernel - Re: [PATCH v17 01/12] power: reset: reboot-mode: Remove devres based allocations

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Message-ID: <20251110130159.pzfmh7mr3p7xz5o7@hu-mojha-hyd.qualcomm.com>
Date: Mon, 10 Nov 2025 18:31:59 +0530
From: Mukesh Ojha <mukesh.ojha@....qualcomm.com>
To: Shivendra Pratap <shivendra.pratap@....qualcomm.com>
Cc: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Sebastian Reichel <sre@...nel.org>, Rob Herring <robh@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Souvik Chakravarty <Souvik.Chakravarty@....com>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>, Andy Yan <andy.yan@...k-chips.com>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Arnd Bergmann <arnd@...db.de>, Konrad Dybcio <konradybcio@...nel.org>,
        cros-qcom-dts-watchers@...omium.org, Vinod Koul <vkoul@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Florian Fainelli <florian.fainelli@...adcom.com>,
        Moritz Fischer <moritz.fischer@...us.com>,
        John Stultz <john.stultz@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        Stephen Boyd <swboyd@...omium.org>,
        Andre Draszik <andre.draszik@...aro.org>,
        Kathiravan Thirumoorthy <kathiravan.thirumoorthy@....qualcomm.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org,
        Elliot Berman <quic_eberman@...cinc.com>,
        Xin Liu <xin.liu@....qualcomm.com>,
        Srinivas Kandagatla <srini@...nel.org>
Subject: Re: [PATCH v17 01/12] power: reset: reboot-mode: Remove devres based
 allocations

On Sun, Nov 09, 2025 at 08:07:14PM +0530, Shivendra Pratap wrote:
> Devres APIs are intended for use in drivers, and they should be
> avoided in shared subsystem code which is being used by multiple
> drivers. Avoid using devres based allocations in the reboot-mode
> subsystem and manually free the resources.
> 
> Replace devm_kzalloc with kzalloc and handle memory cleanup
> explicitly.
> 
> Fixes: 4fcd504edbf7 ("power: reset: add reboot mode driver")
> Signed-off-by: Shivendra Pratap <shivendra.pratap@....qualcomm.com>
> ---
>  drivers/power/reset/reboot-mode.c | 30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
> index fba53f638da04655e756b5f8b7d2d666d1379535..ac4223794083f36960b2bd37a601b7e1f1872de5 100644
> --- a/drivers/power/reset/reboot-mode.c
> +++ b/drivers/power/reset/reboot-mode.c
> @@ -3,6 +3,8 @@
>   * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>   */
>  
> +#define pr_fmt(fmt)	"reboot-mode: " fmt
> +
>  #include <linux/device.h>
>  #include <linux/init.h>
>  #include <linux/kernel.h>
> @@ -71,6 +73,7 @@ static int reboot_mode_notify(struct notifier_block *this,
>  int reboot_mode_register(struct reboot_mode_driver *reboot)
>  {
>  	struct mode_info *info;
> +	struct mode_info *next;
>  	struct property *prop;
>  	struct device_node *np = reboot->dev->of_node;
>  	size_t len = strlen(PREFIX);
> @@ -82,29 +85,27 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  		if (strncmp(prop->name, PREFIX, len))
>  			continue;
>  
> -		info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL);
> +		info = kzalloc(sizeof(*info), GFP_KERNEL);
>  		if (!info) {
>  			ret = -ENOMEM;
>  			goto error;
>  		}
>  
>  		if (of_property_read_u32(np, prop->name, &info->magic)) {
> -			dev_err(reboot->dev, "reboot mode %s without magic number\n",
> -				info->mode);
> -			devm_kfree(reboot->dev, info);
> +			pr_err("reboot mode %s without magic number\n", info->mode);
> +			kfree(info);

This as well could be avoided if we move the above memory allocation
after of_property_read_u32()

>  			continue;
>  		}
>  
>  		info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
>  		if (!info->mode) {
>  			ret =  -ENOMEM;
> -			goto error;
> +			goto err_info;
>  		} else if (info->mode[0] == '\0') {
>  			kfree_const(info->mode);
>  			ret = -EINVAL;
> -			dev_err(reboot->dev, "invalid mode name(%s): too short!\n",
> -				prop->name);
> -			goto error;
> +			pr_err("invalid mode name(%s): too short!\n", prop->name);
> +			goto err_info;
>  		}
>  
>  		list_add_tail(&info->list, &reboot->head);
> @@ -115,9 +116,14 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  
>  	return 0;
>  
> +err_info:

free_info ?

> +	kfree(info);
>  error:
> -	list_for_each_entry(info, &reboot->head, list)
> +	list_for_each_entry_safe(info, next, &reboot->head, list) {
> +		list_del(&info->list);
>  		kfree_const(info->mode);
> +		kfree(info);
> +	}
>  
>  	return ret;
>  }
> @@ -130,11 +136,15 @@ EXPORT_SYMBOL_GPL(reboot_mode_register);
>  int reboot_mode_unregister(struct reboot_mode_driver *reboot)
>  {
>  	struct mode_info *info;
> +	struct mode_info *next;
>  
>  	unregister_reboot_notifier(&reboot->reboot_notifier);
>  
> -	list_for_each_entry(info, &reboot->head, list)
> +	list_for_each_entry_safe(info, next, &reboot->head, list) {
> +		list_del(&info->list);
>  		kfree_const(info->mode);
> +		kfree(info);
> +	}
>  
>  	return 0;
>  }
> 
> -- 
> 2.34.1
> 

-- 
-Mukesh Ojha