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Message-ID: <1336996035.1628.2.camel@shrek.rexursive.com>
Date: Mon, 14 May 2012 21:47:15 +1000
From: Bojan Smojver <bojan@...ursive.com>
To: Alan Stern <stern@...land.harvard.edu>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
"Rafael J. Wysocki" <rjw@...k.pl>,
Linux PM list <linux-pm@...r.kernel.org>,
Kernel development list <linux-kernel@...r.kernel.org>,
bp@...en8.de
Subject: Re: [PATCH]: In kernel hibernation, suspend to both
On Mon, 2012-05-14 at 21:11 +1000, Bojan Smojver wrote:
> Totally untested...
No. That hangs my box.
This triggers a bug in workqueues code (essentially the same as the
previous patch, except for sys_sync() not being done):
---------------
Documentation/power/swsusp.txt | 5 +++
kernel/power/hibernate.c | 36 ++++++++++++++++++
kernel/power/power.h | 6 +++
kernel/power/suspend.c | 79 +++++++++++++++++++++++++++++++---------
kernel/power/swap.c | 28 ++++++++++++++
5 files changed, 137 insertions(+), 17 deletions(-)
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index ac190cf..92341b8 100644
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -33,6 +33,11 @@ echo shutdown > /sys/power/disk; echo disk > /sys/power/state
echo platform > /sys/power/disk; echo disk > /sys/power/state
+. If you would like to write hibernation image to swap and then suspend
+to RAM (provided your platform supports it), you can try
+
+echo suspend > /sys/power/disk; echo disk > /sys/power/state
+
. If you have SATA disks, you'll need recent kernels with SATA suspend
support. For suspend and resume to work, make sure your disk drivers
are built into kernel -- not modules. [There's way to make
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e09dfbf..f48a9ba 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -5,6 +5,7 @@
* Copyright (c) 2003 Open Source Development Lab
* Copyright (c) 2004 Pavel Machek <pavel@....cz>
* Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
+ * Copyright (C) 2012 Bojan Smojver <bojan@...ursive.com>
*
* This file is released under the GPLv2.
*/
@@ -44,6 +45,9 @@ enum {
HIBERNATION_PLATFORM,
HIBERNATION_SHUTDOWN,
HIBERNATION_REBOOT,
+#ifdef CONFIG_SUSPEND
+ HIBERNATION_SUSPEND,
+#endif
/* keep last */
__HIBERNATION_AFTER_LAST
};
@@ -572,6 +576,10 @@ int hibernation_platform_enter(void)
*/
static void power_down(void)
{
+#ifdef CONFIG_SUSPEND
+ int error;
+#endif
+
switch (hibernation_mode) {
case HIBERNATION_REBOOT:
kernel_restart(NULL);
@@ -581,6 +589,25 @@ static void power_down(void)
case HIBERNATION_SHUTDOWN:
kernel_power_off();
break;
+#ifdef CONFIG_SUSPEND
+ case HIBERNATION_SUSPEND:
+ error = suspend_locked(PM_SUSPEND_MEM);
+ if (error) {
+ if (hibernation_ops)
+ hibernation_mode = HIBERNATION_PLATFORM;
+ else
+ hibernation_mode = HIBERNATION_SHUTDOWN;
+ power_down();
+ }
+ /*
+ * Restore swap signature.
+ */
+ error = swsusp_unmark();
+ if (error)
+ printk(KERN_ERR "PM: Swap will be unusable! "
+ "Try swapon -a.\n");
+ return;
+#endif
}
kernel_halt();
/*
@@ -814,6 +841,9 @@ static const char * const hibernation_modes[] = {
[HIBERNATION_PLATFORM] = "platform",
[HIBERNATION_SHUTDOWN] = "shutdown",
[HIBERNATION_REBOOT] = "reboot",
+#ifdef CONFIG_SUSPEND
+ [HIBERNATION_SUSPEND] = "suspend",
+#endif
};
/*
@@ -854,6 +884,9 @@ static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
switch (i) {
case HIBERNATION_SHUTDOWN:
case HIBERNATION_REBOOT:
+#ifdef CONFIG_SUSPEND
+ case HIBERNATION_SUSPEND:
+#endif
break;
case HIBERNATION_PLATFORM:
if (hibernation_ops)
@@ -894,6 +927,9 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
switch (mode) {
case HIBERNATION_SHUTDOWN:
case HIBERNATION_REBOOT:
+#ifdef CONFIG_SUSPEND
+ case HIBERNATION_SUSPEND:
+#endif
hibernation_mode = mode;
break;
case HIBERNATION_PLATFORM:
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 98f3622..cb8e09e 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -156,6 +156,9 @@ extern void swsusp_free(void);
extern int swsusp_read(unsigned int *flags_p);
extern int swsusp_write(unsigned int flags);
extern void swsusp_close(fmode_t);
+#ifdef CONFIG_SUSPEND
+extern int swsusp_unmark(void);
+#endif
/* kernel/power/block_io.c */
extern struct block_device *hib_resume_bdev;
@@ -177,6 +180,9 @@ extern const char *const pm_states[];
extern bool valid_state(suspend_state_t state);
extern int suspend_devices_and_enter(suspend_state_t state);
+#ifdef CONFIG_HIBERNATION
+extern int suspend_locked(suspend_state_t state);
+#endif
#else /* !CONFIG_SUSPEND */
static inline int suspend_devices_and_enter(suspend_state_t state)
{
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 396d262..3402d6e 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -261,28 +261,19 @@ static void suspend_finish(void)
* enter_state - Do common work needed to enter system sleep state.
* @state: System sleep state to enter.
*
- * Make sure that no one else is trying to put the system into a sleep state.
- * Fail if that's not the case. Otherwise, prepare for system suspend, make the
- * system enter the given sleep state and clean up after wakeup.
+ * The system lock needs to be held already when this function is called.
*/
-static int enter_state(suspend_state_t state)
+static int enter_state_locked(suspend_state_t state)
{
int error;
if (!valid_state(state))
return -ENODEV;
- if (!mutex_trylock(&pm_mutex))
- return -EBUSY;
-
- printk(KERN_INFO "PM: Syncing filesystems ... ");
- sys_sync();
- printk("done.\n");
-
pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
error = suspend_prepare();
if (error)
- goto Unlock;
+ return error;
if (suspend_test(TEST_FREEZER))
goto Finish;
@@ -295,26 +286,54 @@ static int enter_state(suspend_state_t state)
Finish:
pr_debug("PM: Finishing wakeup.\n");
suspend_finish();
- Unlock:
+ return error;
+}
+
+/**
+ * enter_state - Do common work needed to enter system sleep state.
+ * @state: System sleep state to enter.
+ *
+ * Make sure that no one else is trying to put the system into a sleep state.
+ * Fail if that's not the case. Otherwise, prepare for system suspend, make the
+ * system enter the given sleep state and clean up after wakeup.
+ */
+static int enter_state(suspend_state_t state)
+{
+ int error;
+
+ if (!valid_state(state))
+ return -ENODEV;
+
+ if (!mutex_trylock(&pm_mutex))
+ return -EBUSY;
+
+ printk(KERN_INFO "PM: Syncing filesystems ... ");
+ sys_sync();
+ printk("done.\n");
+
+ error = enter_state_locked(state);
+
mutex_unlock(&pm_mutex);
return error;
}
/**
- * pm_suspend - Externally visible function for suspending the system.
+ * suspend - Suspend the system.
* @state: System sleep state to enter.
+ * @lock: Whether to acquire a system lock.
*
* Check if the value of @state represents one of the supported states,
- * execute enter_state() and update system suspend statistics.
+ * execute enter_state() or enter_state_locked() and update system suspend
+ * statistics.
*/
-int pm_suspend(suspend_state_t state)
+static int suspend(suspend_state_t state, int lock)
{
int error;
if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
return -EINVAL;
- error = enter_state(state);
+ error = lock ? enter_state(state) : enter_state_locked(state);
if (error) {
suspend_stats.fail++;
dpm_save_failed_errno(error);
@@ -323,4 +342,30 @@ int pm_suspend(suspend_state_t state)
}
return error;
}
+
+/**
+ * suspend_locked - Suspend the system when the system lock is already held.
+ * @state: System sleep state to enter.
+ *
+ * Check if the value of @state represents one of the supported states,
+ * execute enter_state_locked() and update system suspend statistics.
+ */
+#ifdef CONFIG_HIBERNATION
+int suspend_locked(suspend_state_t state)
+{
+ return suspend(state, 0);
+}
+#endif
+
+/**
+ * pm_suspend - Externally visible function for suspending the system.
+ * @state: System sleep state to enter.
+ *
+ * Check if the value of @state represents one of the supported states,
+ * execute enter_state() and update system suspend statistics.
+ */
+int pm_suspend(suspend_state_t state)
+{
+ return suspend(state, 1);
+}
EXPORT_SYMBOL(pm_suspend);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index eef311a..1027da8 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -1456,6 +1456,34 @@ void swsusp_close(fmode_t mode)
blkdev_put(hib_resume_bdev, mode);
}
+/**
+ * swsusp_unmark - Unmark swsusp signature in the resume device
+ */
+
+#ifdef CONFIG_SUSPEND
+int swsusp_unmark(void)
+{
+ int error;
+
+ hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
+ if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
+ memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
+ error = hib_bio_write_page(swsusp_resume_block,
+ swsusp_header, NULL);
+ } else {
+ printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
+ error = -ENODEV;
+ }
+
+ /*
+ * We just returned from suspend, we don't need the image any more.
+ */
+ free_all_swap_pages(root_swap);
+
+ return error;
+}
+#endif
+
static int swsusp_header_init(void)
{
swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
---------------
I think I'll need to break this down into even smaller steps.
PS. It seems obvious now why user space code simply did
suspend_devices_and_enter()... :-)
--
Bojan
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