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From:   Kalesh Singh <kaleshsingh@google.com>
Date:   Wed, 29 Jun 2022 16:19:52 -0700
Message-ID: <CAC_TJvcEzp+zQp50wtj4=7b6vEObpJCQYLaTLhHJCxFdk3TgPg@mail.gmail.com>
Subject: Re: [PATCH] remove CONFIG_ANDROID
To:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Christian Brauner <brauner@kernel.org>,
        Hridya Valsaraju <hridya@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        "Theodore Ts'o" <tytso@mit.edu>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>,
        Paolo Abeni <pabeni@redhat.com>, Rob Herring <robh@kernel.org>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>,
        Neeraj Upadhyay <quic_neeraju@quicinc.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        Shuah Khan <shuah@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, wireguard@lists.zx2c4.com,
        netdev@vger.kernel.org, rcu <rcu@vger.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>, sultan@kerneltoast.com,
        android-kernel-team <android-kernel-team@google.com>,
        John Stultz <jstultz@google.com>,
        Saravana Kannan <saravanak@google.com>, rafael@kernel.org
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On Wed, Jun 29, 2022 at 4:02 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> Hi Kalesh,
>
> On Wed, Jun 29, 2022 at 03:26:33PM -0700, Kalesh Singh wrote:
> > Thanks for taking a look. I'm concerned holding the sys/power/state
> > open would have unintentional side effects. Adding the
> > /sys/power/userspace_autosuspender seems more appropriate. We don't
> > have a use case for the refcounting, so would prefer the simpler
> > writing '0' / '1' to toggle semantics.
>
> Alright. So I've cooked you up some code that you can submit, since I
> assume based on Christoph's bristliness that he won't do so. The below
> adds /sys/power/pm_userspace_autosleeper, which you can write a 0 or a 1
> into, and fixes up wireguard and random.c to use it. The code is
> untested, but should generally be the correct thing, I think.
>
> So in order of operations:
>
> 1. You write a patch for SystemSuspend.cpp and post it on Gerrit.
>
> 2. You take the diff below, clean it up or bikeshed the naming a bit or
>    do whatever there, and submit it to Rafael's PM tree, including as a
>    `Link: ...` this thread and the Gerrit link.
>
> 3. When/if Rafael accepts the patch, you submit the Gerrit CL.
>
> 4. When both have landed, Christoph moves forward with his
>    CONFIG_ANDROID removal.
>
> Does that seem like a reasonable way forward?

Sounds like a plan. I'll clean up and repost your patch once the
Gerrit change is ready.

Thanks,
Kalesh
>
> Jason
>
> diff --git a/drivers/char/random.c b/drivers/char/random.c
> index e3dd1dd3dd22..c25e3be10d9c 100644
> --- a/drivers/char/random.c
> +++ b/drivers/char/random.c
> @@ -756,7 +756,7 @@ static int random_pm_notification(struct notifier_block *nb, unsigned long actio
>
>         if (crng_ready() && (action == PM_RESTORE_PREPARE ||
>             (action == PM_POST_SUSPEND &&
> -            !IS_ENABLED(CONFIG_PM_AUTOSLEEP) && !IS_ENABLED(CONFIG_ANDROID)))) {
> +            !IS_ENABLED(CONFIG_PM_AUTOSLEEP) && !pm_userspace_autosleeper_enabled))) {
>                 crng_reseed();
>                 pr_notice("crng reseeded on system resumption\n");
>         }
> diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c
> index aa9a7a5970fd..1983e0fadb6e 100644
> --- a/drivers/net/wireguard/device.c
> +++ b/drivers/net/wireguard/device.c
> @@ -69,7 +69,7 @@ static int wg_pm_notification(struct notifier_block *nb, unsigned long action, v
>          * its normal operation rather than as a somewhat rare event, then we
>          * don't actually want to clear keys.
>          */
> -       if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || IS_ENABLED(CONFIG_ANDROID))
> +       if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || pm_userspace_autosleeper_enabled)
>                 return 0;
>
>         if (action != PM_HIBERNATION_PREPARE && action != PM_SUSPEND_PREPARE)
> diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> index 70f2921e2e70..0acff26f87b4 100644
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -498,6 +498,7 @@ extern void ksys_sync_helper(void);
>  /* drivers/base/power/wakeup.c */
>  extern bool events_check_enabled;
>  extern suspend_state_t pm_suspend_target_state;
> +extern bool pm_userspace_autosleeper_enabled;
>
>  extern bool pm_wakeup_pending(void);
>  extern void pm_system_wakeup(void);
> @@ -537,6 +538,8 @@ static inline void pm_system_irq_wakeup(unsigned int irq_number) {}
>  static inline void lock_system_sleep(void) {}
>  static inline void unlock_system_sleep(void) {}
>
> +#define pm_userspace_autosleeper_enabled (false)
> +
>  #endif /* !CONFIG_PM_SLEEP */
>
>  #ifdef CONFIG_PM_SLEEP_DEBUG
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index e3694034b753..08f32a281010 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -120,6 +120,23 @@ static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
>
>  power_attr(pm_async);
>
> +bool pm_userspace_autosleeper_enabled;
> +
> +static ssize_t pm_userspace_autosleeper_show(struct kobject *kobj,
> +                               struct kobj_attribute *attr, char *buf)
> +{
> +       return sprintf(buf, "%d\n", pm_userspace_autosleeper_enabled);
> +}
> +
> +static ssize_t pm_userspace_autosleeper_store(struct kobject *kobj,
> +                                   struct kobj_attribute *attr,
> +                                   const char *buf, size_t n)
> +{
> +       return kstrtobool(buf, &pm_userspace_autosleeper_enabled);
> +}
> +
> +power_attr(pm_userspace_autosleeper);
> +
>  #ifdef CONFIG_SUSPEND
>  static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
>                               char *buf)
> @@ -869,6 +886,7 @@ static struct attribute * g[] = {
>  #ifdef CONFIG_PM_SLEEP
>         &pm_async_attr.attr,
>         &wakeup_count_attr.attr,
> +       &pm_userspace_autosleeper.attr,
>  #ifdef CONFIG_SUSPEND
>         &mem_sleep_attr.attr,
>         &sync_on_suspend_attr.attr,
>