linux-kernel - Re: [PATCH v19 01/10] power: reset: reboot-mode: Remove devres based allocations

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Message-ID: <06619e53-7260-7bd2-1954-dd10b92dc354@oss.qualcomm.com>
Date: Mon, 5 Jan 2026 23:23:56 +0530
From: Shivendra Pratap <shivendra.pratap@....qualcomm.com>
To: Bartosz Golaszewski <brgl@...nel.org>
Cc: Lorenzo Pieralisi <lpieralisi@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        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>,
        Andy Yan
 <andy.yan@...k-chips.com>,
        John Stultz <john.stultz@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Moritz Fischer <moritz.fischer@...us.com>,
        Mark Rutland <mark.rutland@....com>,
        Conor Dooley <conor+dt@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Florian Fainelli <florian.fainelli@...adcom.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        Mukesh Ojha <mukesh.ojha@....qualcomm.com>,
        Andre Draszik <andre.draszik@...aro.org>,
        Kathiravan Thirumoorthy <kathiravan.thirumoorthy@....qualcomm.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, Srinivas Kandagatla <srini@...nel.org>
Subject: Re: [PATCH v19 01/10] power: reset: reboot-mode: Remove devres based
 allocations



On 1/2/2026 3:35 PM, Bartosz Golaszewski wrote:
> On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
> <shivendra.pratap@....qualcomm.com> wrote:
>>
>> Devres APIs are intended for use in drivers, where the managed lifetime
>> of resources is tied directly to the driver attach/detach cycle. In
>> shared subsystem code, there is no guarantee that the subsystem
>> functions will only be called after a driver has been attached, nor that
>> they will not be referenced after the managed resources have been
>> released during driver detach.

[SNIP..]

>>
>> @@ -71,9 +74,11 @@ 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);
>> +       u32 magic;
>>         int ret;
>>
>>         INIT_LIST_HEAD(&reboot->head);
>> @@ -82,19 +87,17 @@ 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);
>> +               if (of_property_read_u32(np, prop->name, &magic)) {
> 
> Please use device_property_read_u32() if you have access to a device struct.

Ack. Can it go in same patch with the fixes tag?

> 
>> +                       pr_err("reboot mode %s without magic number\n", prop->name);
> 
> If this is an error, shouldn't we bail out?
> 
>> +                       continue;
>> +               }
>> +
>> +               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);
>> -                       continue;
>> -               }
>> -
>>                 info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
>>                 if (!info->mode) {
>>                         ret =  -ENOMEM;
>> @@ -102,8 +105,7 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>>                 } 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);
>> +                       pr_err("invalid mode name(%s): too short!\n", prop->name);
>>                         goto error;
>>                 }
>>
>> @@ -116,8 +118,12 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>>         return 0;
>>
>>  error:
>> -       list_for_each_entry(info, &reboot->head, list)
>> +       kfree(info);
>> +       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);
>> +       }
> 
> The code is repeated here, maybe factor it out into a separate function?

Ack. let me try that.

thanks,
Shivendra