freezer: Have {,un}lock_system_sleep() save/restore flags

Rafael explained that the reason for having both PF_NOFREEZE and
PF_FREEZER_SKIP is that {,un}lock_system_sleep() is callable from
kthread context that has previously called set_freezable().

In preparation of merging the flags, have {,un}lock_system_slee() save
and restore current->flags.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220822114648.725003428@infradead.org

1 files changed, 22 insertions, 13 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 89c71fce225d..f58a0aa92310 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -92,20 +92,24 @@ bool hibernation_available(void)
  */
 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
 {
+	unsigned int sleep_flags;
+
 	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
 	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
 	    && ops->restore_cleanup && ops->leave)) {
 		WARN_ON(1);
 		return;
 	}
-	lock_system_sleep();
+
+	sleep_flags = lock_system_sleep();
+
 	hibernation_ops = ops;
 	if (ops)
 		hibernation_mode = HIBERNATION_PLATFORM;
 	else if (hibernation_mode == HIBERNATION_PLATFORM)
 		hibernation_mode = HIBERNATION_SHUTDOWN;
 
-	unlock_system_sleep();
+	unlock_system_sleep(sleep_flags);
 }
 EXPORT_SYMBOL_GPL(hibernation_set_ops);
 
@@ -713,6 +717,7 @@ static int load_image_and_restore(void)
 int hibernate(void)
 {
 	bool snapshot_test = false;
+	unsigned int sleep_flags;
 	int error;
 
 	if (!hibernation_available()) {
@@ -720,7 +725,7 @@ int hibernate(void)
 		return -EPERM;
 	}
 
-	lock_system_sleep();
+	sleep_flags = lock_system_sleep();
 	/* The snapshot device should not be opened while we're running */
 	if (!hibernate_acquire()) {
 		error = -EBUSY;
@@ -794,7 +799,7 @@ int hibernate(void)
 	pm_restore_console();
 	hibernate_release();
  Unlock:
-	unlock_system_sleep();
+	unlock_system_sleep(sleep_flags);
 	pr_info("hibernation exit\n");
 
 	return error;
@@ -809,9 +814,10 @@ int hibernate(void)
  */
 int hibernate_quiet_exec(int (*func)(void *data), void *data)
 {
+	unsigned int sleep_flags;
 	int error;
 
-	lock_system_sleep();
+	sleep_flags = lock_system_sleep();
 
 	if (!hibernate_acquire()) {
 		error = -EBUSY;
@@ -891,7 +897,7 @@ restore:
 	hibernate_release();
 
 unlock:
-	unlock_system_sleep();
+	unlock_system_sleep(sleep_flags);
 
 	return error;
 }
@@ -1100,11 +1106,12 @@ static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 			  const char *buf, size_t n)
 {
+	int mode = HIBERNATION_INVALID;
+	unsigned int sleep_flags;
 	int error = 0;
-	int i;
 	int len;
 	char *p;
-	int mode = HIBERNATION_INVALID;
+	int i;
 
 	if (!hibernation_available())
 		return -EPERM;
@@ -1112,7 +1119,7 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 	p = memchr(buf, '\n', n);
 	len = p ? p - buf : n;
 
-	lock_system_sleep();
+	sleep_flags = lock_system_sleep();
 	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 		if (len == strlen(hibernation_modes[i])
 		    && !strncmp(buf, hibernation_modes[i], len)) {
@@ -1142,7 +1149,7 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 	if (!error)
 		pm_pr_dbg("Hibernation mode set to '%s'\n",
 			       hibernation_modes[mode]);
-	unlock_system_sleep();
+	unlock_system_sleep(sleep_flags);
 	return error ? error : n;
 }
 
@@ -1158,9 +1165,10 @@ static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 			    const char *buf, size_t n)
 {
-	dev_t res;
+	unsigned int sleep_flags;
 	int len = n;
 	char *name;
+	dev_t res;
 
 	if (len && buf[len-1] == '\n')
 		len--;
@@ -1173,9 +1181,10 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 	if (!res)
 		return -EINVAL;
 
-	lock_system_sleep();
+	sleep_flags = lock_system_sleep();
 	swsusp_resume_device = res;
-	unlock_system_sleep();
+	unlock_system_sleep(sleep_flags);
+
 	pm_pr_dbg("Configured hibernation resume from disk to %u\n",
 		  swsusp_resume_device);
 	noresume = 0;