[PATCH 1/3] Revert "cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus()"

From: Qais Yousef
Date: Thu Apr 09 2020 - 07:28:12 EST


This issue was fixed already by:

commit d66b16f5df4b ("arm64: Don't use disable_nonboot_cpus()")
commit dddf3578e0d4 ("ARM: Don't use disable_nonboot_cpus()")

The only caller of disable_nonboot_cpus() is x86, which is in a proper
suspend/resume path and due to the reverted patch lost its ability to
early abort due to a pending wakeup.

The fix that is being reverted is arguably a better one to backport to
stable trees. But it highlights the confusion about using
disable_nonboot_cpus() API.

This is a preparation to remove disable_nonboot_cpus() in favor of
freeze_secondary_cpus().

This reverts commit e98eac6ff1b45e4e73f2e6031b37c256ccb5d36b.

Signed-off-by: Qais Yousef <qais.yousef@xxxxxxx>
CC: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
CC: Len Brown <len.brown@xxxxxxxxx>
CC: Pavel Machek <pavel@xxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Borislav Petkov <bp@xxxxxxxxx>
CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
CC: x86@xxxxxxxxxx
CC: Todd E Brandt <todd.e.brandt@xxxxxxxxxxxxxxx>
CC: linux-pm@xxxxxxxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
---
include/linux/cpu.h | 12 +++---------
kernel/cpu.c | 4 ++--
2 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index beaed2dc269e..9ead281157d3 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -144,18 +144,12 @@ static inline void get_online_cpus(void) { cpus_read_lock(); }
static inline void put_online_cpus(void) { cpus_read_unlock(); }

#ifdef CONFIG_PM_SLEEP_SMP
-int __freeze_secondary_cpus(int primary, bool suspend);
-static inline int freeze_secondary_cpus(int primary)
-{
- return __freeze_secondary_cpus(primary, true);
-}
-
+extern int freeze_secondary_cpus(int primary);
static inline int disable_nonboot_cpus(void)
{
- return __freeze_secondary_cpus(0, false);
+ return freeze_secondary_cpus(0);
}
-
-void enable_nonboot_cpus(void);
+extern void enable_nonboot_cpus(void);

static inline int suspend_disable_secondary_cpus(void)
{
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 12ae636e9cb6..30848496cbc7 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1327,7 +1327,7 @@ void bringup_nonboot_cpus(unsigned int setup_max_cpus)
#ifdef CONFIG_PM_SLEEP_SMP
static cpumask_var_t frozen_cpus;

-int __freeze_secondary_cpus(int primary, bool suspend)
+int freeze_secondary_cpus(int primary)
{
int cpu, error = 0;

@@ -1352,7 +1352,7 @@ int __freeze_secondary_cpus(int primary, bool suspend)
if (cpu == primary)
continue;

- if (suspend && pm_wakeup_pending()) {
+ if (pm_wakeup_pending()) {
pr_info("Wakeup pending. Abort CPU freeze\n");
error = -EBUSY;
break;
--
2.17.1