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Next: [PATCH 7/9] PM: Add suspend blocking work.
From: Arve Hjønnevåg on 22 Apr 2010 21:20
This allows active suspend blockers to be listed

Signed-off-by: Arve Hjønnevåg <arve(a)android.com>
---
include/linux/suspend_blocker.h | 6 ++-
kernel/power/suspend_blocker.c | 85 +++++++++++++++++++++++++++-----------
2 files changed, 65 insertions(+), 26 deletions(-)

diff --git a/include/linux/suspend_blocker.h b/include/linux/suspend_blocker.h
index 21689cd..1faa433 100755
--- a/include/linux/suspend_blocker.h
+++ b/include/linux/suspend_blocker.h
@@ -16,8 +16,11 @@
#ifndef _LINUX_SUSPEND_BLOCKER_H
#define _LINUX_SUSPEND_BLOCKER_H

+#include <linux/list.h>
+
/**
* struct suspend_blocker - the basic suspend_blocker structure
+ * @link: List entry for active or inactive list.
* @flags: Tracks initialized and active state.
* @name: Name used for debugging.
*
@@ -29,7 +32,8 @@

struct suspend_blocker {
#ifdef CONFIG_SUSPEND_BLOCKERS
- atomic_t flags;
+ struct list_head link;
+ int flags;
const char *name;
#endif
};
diff --git a/kernel/power/suspend_blocker.c b/kernel/power/suspend_blocker.c
index 1b345d1..868e8f1 100644
--- a/kernel/power/suspend_blocker.c
+++ b/kernel/power/suspend_blocker.c
@@ -32,9 +32,11 @@ module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
#define SB_INITIALIZED (1U << 8)
#define SB_ACTIVE (1U << 9)

+static DEFINE_SPINLOCK(list_lock);
static DEFINE_SPINLOCK(state_lock);
-static atomic_t suspend_block_count;
-static atomic_t current_event_num;
+static LIST_HEAD(inactive_blockers);
+static LIST_HEAD(active_blockers);
+static int current_event_num;
struct workqueue_struct *suspend_work_queue;
struct suspend_blocker main_suspend_blocker;
static suspend_state_t requested_suspend_state = PM_SUSPEND_MEM;
@@ -52,6 +54,14 @@ static bool enable_suspend_blockers;
tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec); \
} while (0);

+static void print_active_blockers_locked(void)
+{
+ struct suspend_blocker *blocker;
+
+ list_for_each_entry(blocker, &active_blockers, link)
+ pr_info("active suspend blocker %s\n", blocker->name);
+}
+
/**
* suspend_is_blocked() - Check if suspend should be blocked
*
@@ -65,7 +75,7 @@ bool suspend_is_blocked(void)
{
if (!enable_suspend_blockers)
return 0;
- return !!atomic_read(&suspend_block_count);
+ return !list_empty(&active_blockers);
}

static void suspend_worker(struct work_struct *work)
@@ -75,13 +85,13 @@ static void suspend_worker(struct work_struct *work)

enable_suspend_blockers = true;
while (!suspend_is_blocked()) {
- entry_event_num = atomic_read(&current_event_num);
+ entry_event_num = current_event_num;
if (debug_mask & DEBUG_SUSPEND)
pr_info("suspend: enter suspend\n");
ret = pm_suspend(requested_suspend_state);
if (debug_mask & DEBUG_EXIT_SUSPEND)
pr_info_time("suspend: exit suspend, ret = %d ", ret);
- if (atomic_read(&current_event_num) == entry_event_num)
+ if (current_event_num == entry_event_num)
pr_info("suspend: pm_suspend returned with no event\n");
}
enable_suspend_blockers = false;
@@ -98,13 +108,20 @@ static DECLARE_WORK(suspend_work, suspend_worker);
*/
void suspend_blocker_init(struct suspend_blocker *blocker, const char *name)
{
+ unsigned long irqflags = 0;
+
WARN_ON(!name);

if (debug_mask & DEBUG_SUSPEND_BLOCKER)
pr_info("suspend_blocker_init name=%s\n", name);

blocker->name = name;
- atomic_set(&blocker->flags, SB_INITIALIZED);
+ blocker->flags = SB_INITIALIZED;
+ INIT_LIST_HEAD(&blocker->link);
+
+ spin_lock_irqsave(&list_lock, irqflags);
+ list_add(&blocker->link, &inactive_blockers);
+ spin_unlock_irqrestore(&list_lock, irqflags);
}
EXPORT_SYMBOL(suspend_blocker_init);

@@ -114,15 +131,17 @@ EXPORT_SYMBOL(suspend_blocker_init);
*/
void suspend_blocker_destroy(struct suspend_blocker *blocker)
{
- int flags;
+ unsigned long irqflags;
+ if (WARN_ON(!(blocker->flags & SB_INITIALIZED)))
+ return;
if (debug_mask & DEBUG_SUSPEND_BLOCKER)
pr_info("suspend_blocker_destroy name=%s\n", blocker->name);
- flags = atomic_xchg(&blocker->flags, 0);
- WARN(!(flags & SB_INITIALIZED), "suspend_blocker_destroy called on "
- "uninitialized suspend_blocker\n");
- if (flags == (SB_INITIALIZED | SB_ACTIVE))
- if (atomic_dec_and_test(&suspend_block_count))
- queue_work(suspend_work_queue, &suspend_work);
+ spin_lock_irqsave(&list_lock, irqflags);
+ blocker->flags &= ~SB_INITIALIZED;
+ list_del(&blocker->link);
+ if ((blocker->flags & SB_ACTIVE) && list_empty(&active_blockers))
+ queue_work(suspend_work_queue, &suspend_work);
+ spin_unlock_irqrestore(&list_lock, irqflags);
}
EXPORT_SYMBOL(suspend_blocker_destroy);

@@ -132,15 +151,20 @@ EXPORT_SYMBOL(suspend_blocker_destroy);
*/
void suspend_block(struct suspend_blocker *blocker)
{
- WARN_ON(!(atomic_read(&blocker->flags) & SB_INITIALIZED));
+ unsigned long irqflags;
+
+ if (WARN_ON(!(blocker->flags & SB_INITIALIZED)))
+ return;

+ spin_lock_irqsave(&list_lock, irqflags);
+ blocker->flags |= SB_ACTIVE;
+ list_del(&blocker->link);
if (debug_mask & DEBUG_SUSPEND_BLOCKER)
pr_info("suspend_block: %s\n", blocker->name);
- if (atomic_cmpxchg(&blocker->flags, SB_INITIALIZED,
- SB_INITIALIZED | SB_ACTIVE) == SB_INITIALIZED)
- atomic_inc(&suspend_block_count);
+ list_add(&blocker->link, &active_blockers);

- atomic_inc(&current_event_num);
+ current_event_num++;
+ spin_unlock_irqrestore(&list_lock, irqflags);
}
EXPORT_SYMBOL(suspend_block);

@@ -152,15 +176,26 @@ EXPORT_SYMBOL(suspend_block);
*/
void suspend_unblock(struct suspend_blocker *blocker)
{
- WARN_ON(!(atomic_read(&blocker->flags) & SB_INITIALIZED));
+ unsigned long irqflags;
+
+ if (WARN_ON(!(blocker->flags & SB_INITIALIZED)))
+ return;
+
+ spin_lock_irqsave(&list_lock, irqflags);

if (debug_mask & DEBUG_SUSPEND_BLOCKER)
pr_info("suspend_unblock: %s\n", blocker->name);
+ list_del(&blocker->link);
+ list_add(&blocker->link, &inactive_blockers);

- if (atomic_cmpxchg(&blocker->flags, SB_INITIALIZED | SB_ACTIVE,
- SB_INITIALIZED) == (SB_INITIALIZED | SB_ACTIVE))
- if (atomic_dec_and_test(&suspend_block_count))
- queue_work(suspend_work_queue, &suspend_work);
+ if ((blocker->flags & SB_ACTIVE) && list_empty(&active_blockers))
+ queue_work(suspend_work_queue, &suspend_work);
+ blocker->flags &= ~(SB_ACTIVE);
+ if (blocker == &main_suspend_blocker) {
+ if (debug_mask & DEBUG_SUSPEND)
+ print_active_blockers_locked();
+ }
+ spin_unlock_irqrestore(&list_lock, irqflags);
}
EXPORT_SYMBOL(suspend_unblock);

@@ -172,9 +207,9 @@ EXPORT_SYMBOL(suspend_unblock);
*/
bool suspend_blocker_is_active(struct suspend_blocker *blocker)
{
- WARN_ON(!(atomic_read(&blocker->flags) & SB_INITIALIZED));
+ WARN_ON(!(blocker->flags & SB_INITIALIZED));

- return !!(atomic_read(&blocker->flags) & SB_ACTIVE);
+ return !!(blocker->flags & SB_ACTIVE);
}
EXPORT_SYMBOL(suspend_blocker_is_active);

--
1.6.5.1

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Prev: [PATCH 0/9] Suspend block api (version 4)
Next: [PATCH 7/9] PM: Add suspend blocking work.