Re: [PATCH v8 2/3] freezer: refactor pm_freezing into a function.
Hi Rafael
On Fri, 2 Dec 2022 at 18:48, Rafael J. Wysocki wrote:
>
> On Thu, Dec 1, 2022 at 12:08 PM Ricardo Ribalda wrote:
> >
> > Add a way to let the drivers know if the processes are frozen.
> >
> > This is needed by drivers that are waiting for processes to end on their
> > shutdown path.
> >
> > Convert pm_freezing into a function and export it, so it can be used by
> > drivers that are either built-in or modules.
> >
> > Cc: sta...@vger.kernel.org
> > Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine
> > drivers in .shutdown")
> > Signed-off-by: Ricardo Ribalda
>
> Why can't you export the original pm_freezing variable and why is this
> fixing anything?
Because then any module will be able to modify the content of the variable.
The Fixes: is because the last patch on the set is doing a real fix.
If you only cherry-pick the last patch on a stable branch, the build
will fail. (Also, the zero-day builder complains)
Anyway, I think we can hold this patch for a bit. The snd people are
discussing if this the way to handle it, or if we should handle
.shutdown in a different way.
Thanks!
>
> > ---
> > include/linux/freezer.h | 3 ++-
> > kernel/freezer.c| 3 +--
> > kernel/power/process.c | 24
> > 3 files changed, 23 insertions(+), 7 deletions(-)
> >
> > diff --git a/include/linux/freezer.h b/include/linux/freezer.h
> > index b303472255be..3413c869d68b 100644
> > --- a/include/linux/freezer.h
> > +++ b/include/linux/freezer.h
> > @@ -13,7 +13,7 @@
> > #ifdef CONFIG_FREEZER
> > DECLARE_STATIC_KEY_FALSE(freezer_active);
> >
> > -extern bool pm_freezing; /* PM freezing in effect */
> > +bool pm_freezing(void);
> > extern bool pm_nosig_freezing; /* PM nosig freezing in effect */
> >
> > /*
> > @@ -80,6 +80,7 @@ static inline int freeze_processes(void) { return
> > -ENOSYS; }
> > static inline int freeze_kernel_threads(void) { return -ENOSYS; }
> > static inline void thaw_processes(void) {}
> > static inline void thaw_kernel_threads(void) {}
> > +static inline bool pm_freezing(void) { return false; }
> >
> > static inline bool try_to_freeze(void) { return false; }
> >
> > diff --git a/kernel/freezer.c b/kernel/freezer.c
> > index 4fad0e6fca64..2d3530ebdb7e 100644
> > --- a/kernel/freezer.c
> > +++ b/kernel/freezer.c
> > @@ -20,7 +20,6 @@ EXPORT_SYMBOL(freezer_active);
> > * indicate whether PM freezing is in effect, protected by
> > * system_transition_mutex
> > */
> > -bool pm_freezing;
> > bool pm_nosig_freezing;
> >
> > /* protects freezing and frozen transitions */
> > @@ -46,7 +45,7 @@ bool freezing_slow_path(struct task_struct *p)
> > if (pm_nosig_freezing || cgroup_freezing(p))
> > return true;
> >
> > - if (pm_freezing && !(p->flags & PF_KTHREAD))
> > + if (pm_freezing() && !(p->flags & PF_KTHREAD))
> > return true;
> >
> > return false;
> > diff --git a/kernel/power/process.c b/kernel/power/process.c
> > index ddd9988327fe..8a4d0e2c8c20 100644
> > --- a/kernel/power/process.c
> > +++ b/kernel/power/process.c
> > @@ -108,6 +108,22 @@ static int try_to_freeze_tasks(bool user_only)
> > return todo ? -EBUSY : 0;
> > }
> >
> > +/*
> > + * Indicate whether PM freezing is in effect, protected by
> > + * system_transition_mutex.
> > + */
> > +static bool pm_freezing_internal;
> > +
> > +/**
> > + * pm_freezing - indicate whether PM freezing is in effect.
> > + *
> > + */
> > +bool pm_freezing(void)
> > +{
> > + return pm_freezing_internal;
> > +}
> > +EXPORT_SYMBOL(pm_freezing);
>
> Use EXPORT_SYMBOL_GPL() instead, please.
>
> > +
> > /**
> > * freeze_processes - Signal user space processes to enter the
> > refrigerator.
> > * The current thread will not be frozen. The same process that calls
> > @@ -126,12 +142,12 @@ int freeze_processes(void)
> > /* Make sure this task doesn't get frozen */
> > current->flags |= PF_SUSPEND_TASK;
> >
> > - if (!pm_freezing)
> > + if (!pm_freezing())
> > static_branch_inc(_active);
> >
> > pm_wakeup_clear(0);
> > pr_info("Freezing user space processes ... ");
> > - pm_freezing = true;
> > + pm_freezing_internal = true;
> > error = try_to_freeze_tasks(true);
> > if (!error) {
> > __usermodehelper_set_disable_depth(UMH_DISABLED);
> > @@ -187,9 +203,9 @@ void thaw_processes(void)
> > struct task_struct *curr = current;
> >
> > trace_suspend_resume(TPS("thaw_processes"), 0, true);
> > - if (pm_freezing)
> > + if (pm_freezing())
> > static_branch_dec(_active);
> > - pm_freezing = false;
> > + pm_freezing_internal = false;
> > pm_nosig_freezing = false;
> >
> > oom_killer_enable();
> >
> > --
>
> --
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Re: [PATCH v8 2/3] freezer: refactor pm_freezing into a function.
On Thu, Dec 1, 2022 at 12:08 PM Ricardo Ribalda wrote:
>
> Add a way to let the drivers know if the processes are frozen.
>
> This is needed by drivers that are waiting for processes to end on their
> shutdown path.
>
> Convert pm_freezing into a function and export it, so it can be used by
> drivers that are either built-in or modules.
>
> Cc: sta...@vger.kernel.org
> Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine drivers
> in .shutdown")
> Signed-off-by: Ricardo Ribalda
Why can't you export the original pm_freezing variable and why is this
fixing anything?
> ---
> include/linux/freezer.h | 3 ++-
> kernel/freezer.c| 3 +--
> kernel/power/process.c | 24
> 3 files changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/freezer.h b/include/linux/freezer.h
> index b303472255be..3413c869d68b 100644
> --- a/include/linux/freezer.h
> +++ b/include/linux/freezer.h
> @@ -13,7 +13,7 @@
> #ifdef CONFIG_FREEZER
> DECLARE_STATIC_KEY_FALSE(freezer_active);
>
> -extern bool pm_freezing; /* PM freezing in effect */
> +bool pm_freezing(void);
> extern bool pm_nosig_freezing; /* PM nosig freezing in effect */
>
> /*
> @@ -80,6 +80,7 @@ static inline int freeze_processes(void) { return -ENOSYS; }
> static inline int freeze_kernel_threads(void) { return -ENOSYS; }
> static inline void thaw_processes(void) {}
> static inline void thaw_kernel_threads(void) {}
> +static inline bool pm_freezing(void) { return false; }
>
> static inline bool try_to_freeze(void) { return false; }
>
> diff --git a/kernel/freezer.c b/kernel/freezer.c
> index 4fad0e6fca64..2d3530ebdb7e 100644
> --- a/kernel/freezer.c
> +++ b/kernel/freezer.c
> @@ -20,7 +20,6 @@ EXPORT_SYMBOL(freezer_active);
> * indicate whether PM freezing is in effect, protected by
> * system_transition_mutex
> */
> -bool pm_freezing;
> bool pm_nosig_freezing;
>
> /* protects freezing and frozen transitions */
> @@ -46,7 +45,7 @@ bool freezing_slow_path(struct task_struct *p)
> if (pm_nosig_freezing || cgroup_freezing(p))
> return true;
>
> - if (pm_freezing && !(p->flags & PF_KTHREAD))
> + if (pm_freezing() && !(p->flags & PF_KTHREAD))
> return true;
>
> return false;
> diff --git a/kernel/power/process.c b/kernel/power/process.c
> index ddd9988327fe..8a4d0e2c8c20 100644
> --- a/kernel/power/process.c
> +++ b/kernel/power/process.c
> @@ -108,6 +108,22 @@ static int try_to_freeze_tasks(bool user_only)
> return todo ? -EBUSY : 0;
> }
>
> +/*
> + * Indicate whether PM freezing is in effect, protected by
> + * system_transition_mutex.
> + */
> +static bool pm_freezing_internal;
> +
> +/**
> + * pm_freezing - indicate whether PM freezing is in effect.
> + *
> + */
> +bool pm_freezing(void)
> +{
> + return pm_freezing_internal;
> +}
> +EXPORT_SYMBOL(pm_freezing);
Use EXPORT_SYMBOL_GPL() instead, please.
> +
> /**
> * freeze_processes - Signal user space processes to enter the refrigerator.
> * The current thread will not be frozen. The same process that calls
> @@ -126,12 +142,12 @@ int freeze_processes(void)
> /* Make sure this task doesn't get frozen */
> current->flags |= PF_SUSPEND_TASK;
>
> - if (!pm_freezing)
> + if (!pm_freezing())
> static_branch_inc(_active);
>
> pm_wakeup_clear(0);
> pr_info("Freezing user space processes ... ");
> - pm_freezing = true;
> + pm_freezing_internal = true;
> error = try_to_freeze_tasks(true);
> if (!error) {
> __usermodehelper_set_disable_depth(UMH_DISABLED);
> @@ -187,9 +203,9 @@ void thaw_processes(void)
> struct task_struct *curr = current;
>
> trace_suspend_resume(TPS("thaw_processes"), 0, true);
> - if (pm_freezing)
> + if (pm_freezing())
> static_branch_dec(_active);
> - pm_freezing = false;
> + pm_freezing_internal = false;
> pm_nosig_freezing = false;
>
> oom_killer_enable();
>
> --
[PATCH v8 2/3] freezer: refactor pm_freezing into a function.
Add a way to let the drivers know if the processes are frozen.
This is needed by drivers that are waiting for processes to end on their
shutdown path.
Convert pm_freezing into a function and export it, so it can be used by
drivers that are either built-in or modules.
Cc: sta...@vger.kernel.org
Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine drivers
in .shutdown")
Signed-off-by: Ricardo Ribalda
sdad
---
include/linux/freezer.h | 3 ++-
kernel/freezer.c| 3 +--
kernel/power/process.c | 24
3 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index b303472255be..3413c869d68b 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -13,7 +13,7 @@
#ifdef CONFIG_FREEZER
DECLARE_STATIC_KEY_FALSE(freezer_active);
-extern bool pm_freezing; /* PM freezing in effect */
+bool pm_freezing(void);
extern bool pm_nosig_freezing; /* PM nosig freezing in effect */
/*
@@ -80,6 +80,7 @@ static inline int freeze_processes(void) { return -ENOSYS; }
static inline int freeze_kernel_threads(void) { return -ENOSYS; }
static inline void thaw_processes(void) {}
static inline void thaw_kernel_threads(void) {}
+static inline bool pm_freezing(void) { return false; }
static inline bool try_to_freeze(void) { return false; }
diff --git a/kernel/freezer.c b/kernel/freezer.c
index 4fad0e6fca64..2d3530ebdb7e 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -20,7 +20,6 @@ EXPORT_SYMBOL(freezer_active);
* indicate whether PM freezing is in effect, protected by
* system_transition_mutex
*/
-bool pm_freezing;
bool pm_nosig_freezing;
/* protects freezing and frozen transitions */
@@ -46,7 +45,7 @@ bool freezing_slow_path(struct task_struct *p)
if (pm_nosig_freezing || cgroup_freezing(p))
return true;
- if (pm_freezing && !(p->flags & PF_KTHREAD))
+ if (pm_freezing() && !(p->flags & PF_KTHREAD))
return true;
return false;
diff --git a/kernel/power/process.c b/kernel/power/process.c
index ddd9988327fe..8a4d0e2c8c20 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -108,6 +108,22 @@ static int try_to_freeze_tasks(bool user_only)
return todo ? -EBUSY : 0;
}
+/*
+ * Indicate whether PM freezing is in effect, protected by
+ * system_transition_mutex.
+ */
+static bool pm_freezing_internal;
+
+/**
+ * pm_freezing - indicate whether PM freezing is in effect.
+ *
+ */
+bool pm_freezing(void)
+{
+ return pm_freezing_internal;
+}
+EXPORT_SYMBOL(pm_freezing);
+
/**
* freeze_processes - Signal user space processes to enter the refrigerator.
* The current thread will not be frozen. The same process that calls
@@ -126,12 +142,12 @@ int freeze_processes(void)
/* Make sure this task doesn't get frozen */
current->flags |= PF_SUSPEND_TASK;
- if (!pm_freezing)
+ if (!pm_freezing())
static_branch_inc(_active);
pm_wakeup_clear(0);
pr_info("Freezing user space processes ... ");
- pm_freezing = true;
+ pm_freezing_internal = true;
error = try_to_freeze_tasks(true);
if (!error) {
__usermodehelper_set_disable_depth(UMH_DISABLED);
@@ -187,9 +203,9 @@ void thaw_processes(void)
struct task_struct *curr = current;
trace_suspend_resume(TPS("thaw_processes"), 0, true);
- if (pm_freezing)
+ if (pm_freezing())
static_branch_dec(_active);
- pm_freezing = false;
+ pm_freezing_internal = false;
pm_nosig_freezing = false;
oom_killer_enable();
--
2.39.0.rc0.267.gcb52ba06e7-goog-b4-0.11.0-dev-696ae
