[PATCH 9/9] PM: suspend_block: Add timeout support to user-space suspend_blockers

Arve Hjønnevåg
2009-05-06T04:18:49Z

This also allows a grace period to be set where suspend is blocked for a while
if a user-space suspend_blocker is destroyed while it was active.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
Documentation/power/suspend-blockers.txt | 7 +++++++
include/linux/suspend_block_dev.h | 1 +
kernel/power/user_suspend_blocker.c | 23 +++++++++++++++++++++++
3 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/Documentation/power/suspend-blockers.txt b/Documentation/power/suspend-blockers.txt
index bc9d57a..3612794 100644
--- a/Documentation/power/suspend-blockers.txt
+++ b/Documentation/power/suspend-blockers.txt
@@ -112,6 +112,8 @@ then call:

To activate a suspend_blocker call:
ioctl(fd, SUSPEND_BLOCKER_IOCTL_BLOCK);
+or
+ ioctl(fd, SUSPEND_BLOCKER_IOCTL_BLOCK_TIMEOUT, &timespec_timeout);

To unblock call:
ioctl(fd, SUSPEND_BLOCKER_IOCTL_UNBLOCK);
@@ -119,3 +121,8 @@ To unblock call:
To destroy the suspend_blocker, close the device:
close(fd);

+A module parameter, unclean_exit_grace_period, can be set to allow servers
+some time to restart if they crash with an active suspend_blocker. If the
+process dies or the device is closed while the suspend_blocker is active, a
+suspend_blocker will be held for the number of seconds specified.
+
diff --git a/include/linux/suspend_block_dev.h b/include/linux/suspend_block_dev.h
index a7c0bf9..cff4943 100644
--- a/include/linux/suspend_block_dev.h
+++ b/include/linux/suspend_block_dev.h
@@ -20,6 +20,7 @@

#define SUSPEND_BLOCKER_IOCTL_INIT(len) _IOC(_IOC_WRITE, 's', 0, len)
#define SUSPEND_BLOCKER_IOCTL_BLOCK _IO('s', 1)
+#define SUSPEND_BLOCKER_IOCTL_BLOCK_TIMEOUT _IOW('s', 2, struct timespec)
#define SUSPEND_BLOCKER_IOCTL_UNBLOCK _IO('s', 3)

#endif
diff --git a/kernel/power/user_suspend_blocker.c b/kernel/power/user_suspend_blocker.c
index 69b3ddb..b853f66 100644
--- a/kernel/power/user_suspend_blocker.c
+++ b/kernel/power/user_suspend_blocker.c
@@ -26,7 +26,12 @@ enum {
static int debug_mask = DEBUG_FAILURE;
module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);

+static int unclean_exit_grace_period;
+module_param_named(unclean_exit_grace_period, unclean_exit_grace_period, int,
+ S_IRUGO | S_IWUSR | S_IWGRP);
+
static DEFINE_MUTEX(ioctl_lock);
+static struct suspend_blocker unclean_exit_suspend_blocker;

struct user_suspend_blocker {
struct suspend_blocker blocker;
@@ -58,6 +63,8 @@ static long user_suspend_blocker_ioctl(struct file *file, unsigned int cmd,
{
void __user *arg = (void __user *)_arg;
struct user_suspend_blocker *bl;
+ struct timespec ts;
+ unsigned long timeout;
long ret;

mutex_lock(&ioctl_lock);
@@ -75,6 +82,15 @@ static long user_suspend_blocker_ioctl(struct file *file, unsigned int cmd,
suspend_block(&bl->blocker);
ret = 0;
break;
+ case SUSPEND_BLOCKER_IOCTL_BLOCK_TIMEOUT:
+ if (copy_from_user(&ts, arg, sizeof(ts))) {
+ ret = -EFAULT;
+ goto done;
+ }
+ timeout = timespec_to_jiffies(&ts);
+ suspend_block_timeout(&bl->blocker, timeout);
+ ret = 0;
+ break;
case SUSPEND_BLOCKER_IOCTL_UNBLOCK:
suspend_unblock(&bl->blocker);
ret = 0;
@@ -95,6 +111,10 @@ static int user_suspend_blocker_release(struct inode *inode, struct file *file)
struct user_suspend_blocker *bl = file->private_data;
if (!bl)
return 0;
+ if (suspend_blocker_is_active(&bl->blocker) &&
+ unclean_exit_grace_period)
+ suspend_block_timeout(&unclean_exit_suspend_blocker,
+ unclean_exit_grace_period * HZ);
suspend_blocker_destroy(&bl->blocker);
kfree(bl);
return 0;
@@ -113,12 +133,15 @@ struct miscdevice user_suspend_blocker_device = {

static int __init user_suspend_blocker_init(void)
{
+ suspend_blocker_init(&unclean_exit_suspend_blocker,
+ "user-unclean-exit");
return misc_register(&user_suspend_blocker_device);
}

static void __exit user_suspend_blocker_exit(void)
{
misc_deregister(&user_suspend_blocker_device);
+ suspend_blocker_destroy(&unclean_exit_suspend_blocker);
}

module_init(user_suspend_blocker_init);
--
1.6.1

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