Re: [PATCH v8 2/3] freezer: refactor pm_freezing into a function.
From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: 2022-12-02 17:48:17
Also in:
alsa-devel, kexec, linux-efi, linux-hyperv, linux-pci, linux-pm, lkml, stable, xen-devel
On Thu, Dec 1, 2022 at 12:08 PM Ricardo Ribalda [off-list ref] 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: stable@vger.kernel.org
Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine drivers in .shutdown")
Signed-off-by: Ricardo Ribalda <redacted>Why can't you export the original pm_freezing variable and why is this fixing anything?
quoted hunk ↗ jump to hunk
--- 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.
quoted hunk ↗ jump to hunk
+ /** * 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(&freezer_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(&freezer_active); - pm_freezing = false; + pm_freezing_internal = false; pm_nosig_freezing = false; oom_killer_enable(); --