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authorLinus Torvalds <torvalds@linux-foundation.org>2012-04-04 14:26:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-04 14:26:40 -0700
commit64ebe987311853ea857a244439de5b947a4b1b07 (patch)
treeb33ab6efd7f118e0f6ab5a6bcbd59ba31a313da5 /kernel
parenta5149bf3fed59b94207809704b5d06fec337a771 (diff)
parentc4772d192c70b61d52262b0db76f7abd8aeb51c6 (diff)
downloadlinux-64ebe987311853ea857a244439de5b947a4b1b07.tar.gz
Merge tag 'pm-for-3.4-part-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more power management updates from Rafael Wysocki: - Patch series that hopefully fixes races between the freezer and request_firmware() and request_firmware_nowait() for good, with two cleanups from Stephen Boyd on top. - Runtime PM fix from Alan Stern preventing tasks from getting stuck indefinitely in the runtime PM wait queue. - Device PM QoS update from MyungJoo Ham introducing a new variant of pm_qos_update_request() allowing the callers to specify a timeout. * tag 'pm-for-3.4-part-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM / QoS: add pm_qos_update_request_timeout() API firmware_class: Move request_firmware_nowait() to workqueues firmware_class: Reorganize fw_create_instance() PM / Sleep: Mitigate race between the freezer and request_firmware() PM / Sleep: Move disabling of usermode helpers to the freezer PM / Hibernate: Disable usermode helpers right before freezing tasks firmware_class: Do not warn that system is not ready from async loads firmware_class: Split _request_firmware() into three functions, v2 firmware_class: Rework usermodehelper check PM / Runtime: don't forget to wake up waitqueue on failure
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kmod.c117
-rw-r--r--kernel/power/hibernate.c18
-rw-r--r--kernel/power/process.c8
-rw-r--r--kernel/power/qos.c50
-rw-r--r--kernel/power/suspend.c7
-rw-r--r--kernel/power/user.c10
6 files changed, 148 insertions, 62 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 957a7aab8eb..05698a7415f 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -322,7 +322,7 @@ static void __call_usermodehelper(struct work_struct *work)
* land has been frozen during a system-wide hibernation or suspend operation).
* Should always be manipulated under umhelper_sem acquired for write.
*/
-static int usermodehelper_disabled = 1;
+static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED;
/* Number of helpers running */
static atomic_t running_helpers = ATOMIC_INIT(0);
@@ -334,32 +334,110 @@ static atomic_t running_helpers = ATOMIC_INIT(0);
static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
/*
+ * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled
+ * to become 'false'.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq);
+
+/*
* Time to wait for running_helpers to become zero before the setting of
* usermodehelper_disabled in usermodehelper_disable() fails
*/
#define RUNNING_HELPERS_TIMEOUT (5 * HZ)
-void read_lock_usermodehelper(void)
+int usermodehelper_read_trylock(void)
{
+ DEFINE_WAIT(wait);
+ int ret = 0;
+
down_read(&umhelper_sem);
+ for (;;) {
+ prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
+ TASK_INTERRUPTIBLE);
+ if (!usermodehelper_disabled)
+ break;
+
+ if (usermodehelper_disabled == UMH_DISABLED)
+ ret = -EAGAIN;
+
+ up_read(&umhelper_sem);
+
+ if (ret)
+ break;
+
+ schedule();
+ try_to_freeze();
+
+ down_read(&umhelper_sem);
+ }
+ finish_wait(&usermodehelper_disabled_waitq, &wait);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_trylock);
+
+long usermodehelper_read_lock_wait(long timeout)
+{
+ DEFINE_WAIT(wait);
+
+ if (timeout < 0)
+ return -EINVAL;
+
+ down_read(&umhelper_sem);
+ for (;;) {
+ prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
+ TASK_UNINTERRUPTIBLE);
+ if (!usermodehelper_disabled)
+ break;
+
+ up_read(&umhelper_sem);
+
+ timeout = schedule_timeout(timeout);
+ if (!timeout)
+ break;
+
+ down_read(&umhelper_sem);
+ }
+ finish_wait(&usermodehelper_disabled_waitq, &wait);
+ return timeout;
}
-EXPORT_SYMBOL_GPL(read_lock_usermodehelper);
+EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait);
-void read_unlock_usermodehelper(void)
+void usermodehelper_read_unlock(void)
{
up_read(&umhelper_sem);
}
-EXPORT_SYMBOL_GPL(read_unlock_usermodehelper);
+EXPORT_SYMBOL_GPL(usermodehelper_read_unlock);
/**
- * usermodehelper_disable - prevent new helpers from being started
+ * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled.
+ * depth: New value to assign to usermodehelper_disabled.
+ *
+ * Change the value of usermodehelper_disabled (under umhelper_sem locked for
+ * writing) and wakeup tasks waiting for it to change.
*/
-int usermodehelper_disable(void)
+void __usermodehelper_set_disable_depth(enum umh_disable_depth depth)
+{
+ down_write(&umhelper_sem);
+ usermodehelper_disabled = depth;
+ wake_up(&usermodehelper_disabled_waitq);
+ up_write(&umhelper_sem);
+}
+
+/**
+ * __usermodehelper_disable - Prevent new helpers from being started.
+ * @depth: New value to assign to usermodehelper_disabled.
+ *
+ * Set usermodehelper_disabled to @depth and wait for running helpers to exit.
+ */
+int __usermodehelper_disable(enum umh_disable_depth depth)
{
long retval;
+ if (!depth)
+ return -EINVAL;
+
down_write(&umhelper_sem);
- usermodehelper_disabled = 1;
+ usermodehelper_disabled = depth;
up_write(&umhelper_sem);
/*
@@ -374,31 +452,10 @@ int usermodehelper_disable(void)
if (retval)
return 0;
- down_write(&umhelper_sem);
- usermodehelper_disabled = 0;
- up_write(&umhelper_sem);
+ __usermodehelper_set_disable_depth(UMH_ENABLED);
return -EAGAIN;
}
-/**
- * usermodehelper_enable - allow new helpers to be started again
- */
-void usermodehelper_enable(void)
-{
- down_write(&umhelper_sem);
- usermodehelper_disabled = 0;
- up_write(&umhelper_sem);
-}
-
-/**
- * usermodehelper_is_disabled - check if new helpers are allowed to be started
- */
-bool usermodehelper_is_disabled(void)
-{
- return usermodehelper_disabled;
-}
-EXPORT_SYMBOL_GPL(usermodehelper_is_disabled);
-
static void helper_lock(void)
{
atomic_inc(&running_helpers);
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 0a186cfde78..e09dfbfeece 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -16,7 +16,6 @@
#include <linux/string.h>
#include <linux/device.h>
#include <linux/async.h>
-#include <linux/kmod.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/mount.h>
@@ -611,14 +610,10 @@ int hibernate(void)
if (error)
goto Exit;
- error = usermodehelper_disable();
- if (error)
- goto Exit;
-
/* Allocate memory management structures */
error = create_basic_memory_bitmaps();
if (error)
- goto Enable_umh;
+ goto Exit;
printk(KERN_INFO "PM: Syncing filesystems ... ");
sys_sync();
@@ -661,8 +656,6 @@ int hibernate(void)
Free_bitmaps:
free_basic_memory_bitmaps();
- Enable_umh:
- usermodehelper_enable();
Exit:
pm_notifier_call_chain(PM_POST_HIBERNATION);
pm_restore_console();
@@ -777,15 +770,9 @@ static int software_resume(void)
if (error)
goto close_finish;
- error = usermodehelper_disable();
- if (error)
- goto close_finish;
-
error = create_basic_memory_bitmaps();
- if (error) {
- usermodehelper_enable();
+ if (error)
goto close_finish;
- }
pr_debug("PM: Preparing processes for restore.\n");
error = freeze_processes();
@@ -806,7 +793,6 @@ static int software_resume(void)
thaw_processes();
Done:
free_basic_memory_bitmaps();
- usermodehelper_enable();
Finish:
pm_notifier_call_chain(PM_POST_RESTORE);
pm_restore_console();
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 0d2aeb22610..19db29f6755 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -16,6 +16,7 @@
#include <linux/freezer.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
+#include <linux/kmod.h>
/*
* Timeout for stopping processes
@@ -122,6 +123,10 @@ int freeze_processes(void)
{
int error;
+ error = __usermodehelper_disable(UMH_FREEZING);
+ if (error)
+ return error;
+
if (!pm_freezing)
atomic_inc(&system_freezing_cnt);
@@ -130,6 +135,7 @@ int freeze_processes(void)
error = try_to_freeze_tasks(true);
if (!error) {
printk("done.");
+ __usermodehelper_set_disable_depth(UMH_DISABLED);
oom_killer_disable();
}
printk("\n");
@@ -187,6 +193,8 @@ void thaw_processes(void)
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
+ usermodehelper_enable();
+
schedule();
printk("done.\n");
}
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index d6d6dbd1ecc..6a031e68402 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -230,6 +230,21 @@ int pm_qos_request_active(struct pm_qos_request *req)
EXPORT_SYMBOL_GPL(pm_qos_request_active);
/**
+ * pm_qos_work_fn - the timeout handler of pm_qos_update_request_timeout
+ * @work: work struct for the delayed work (timeout)
+ *
+ * This cancels the timeout request by falling back to the default at timeout.
+ */
+static void pm_qos_work_fn(struct work_struct *work)
+{
+ struct pm_qos_request *req = container_of(to_delayed_work(work),
+ struct pm_qos_request,
+ work);
+
+ pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE);
+}
+
+/**
* pm_qos_add_request - inserts new qos request into the list
* @req: pointer to a preallocated handle
* @pm_qos_class: identifies which list of qos request to use
@@ -253,6 +268,7 @@ void pm_qos_add_request(struct pm_qos_request *req,
return;
}
req->pm_qos_class = pm_qos_class;
+ INIT_DELAYED_WORK(&req->work, pm_qos_work_fn);
pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,
&req->node, PM_QOS_ADD_REQ, value);
}
@@ -279,6 +295,9 @@ void pm_qos_update_request(struct pm_qos_request *req,
return;
}
+ if (delayed_work_pending(&req->work))
+ cancel_delayed_work_sync(&req->work);
+
if (new_value != req->node.prio)
pm_qos_update_target(
pm_qos_array[req->pm_qos_class]->constraints,
@@ -287,6 +306,34 @@ void pm_qos_update_request(struct pm_qos_request *req,
EXPORT_SYMBOL_GPL(pm_qos_update_request);
/**
+ * pm_qos_update_request_timeout - modifies an existing qos request temporarily.
+ * @req : handle to list element holding a pm_qos request to use
+ * @new_value: defines the temporal qos request
+ * @timeout_us: the effective duration of this qos request in usecs.
+ *
+ * After timeout_us, this qos request is cancelled automatically.
+ */
+void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value,
+ unsigned long timeout_us)
+{
+ if (!req)
+ return;
+ if (WARN(!pm_qos_request_active(req),
+ "%s called for unknown object.", __func__))
+ return;
+
+ if (delayed_work_pending(&req->work))
+ cancel_delayed_work_sync(&req->work);
+
+ if (new_value != req->node.prio)
+ pm_qos_update_target(
+ pm_qos_array[req->pm_qos_class]->constraints,
+ &req->node, PM_QOS_UPDATE_REQ, new_value);
+
+ schedule_delayed_work(&req->work, usecs_to_jiffies(timeout_us));
+}
+
+/**
* pm_qos_remove_request - modifies an existing qos request
* @req: handle to request list element
*
@@ -305,6 +352,9 @@ void pm_qos_remove_request(struct pm_qos_request *req)
return;
}
+ if (delayed_work_pending(&req->work))
+ cancel_delayed_work_sync(&req->work);
+
pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints,
&req->node, PM_QOS_REMOVE_REQ,
PM_QOS_DEFAULT_VALUE);
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 88e5c967370..396d262b8fd 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -12,7 +12,6 @@
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
-#include <linux/kmod.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/syscalls.h>
@@ -102,17 +101,12 @@ static int suspend_prepare(void)
if (error)
goto Finish;
- error = usermodehelper_disable();
- if (error)
- goto Finish;
-
error = suspend_freeze_processes();
if (!error)
return 0;
suspend_stats.failed_freeze++;
dpm_save_failed_step(SUSPEND_FREEZE);
- usermodehelper_enable();
Finish:
pm_notifier_call_chain(PM_POST_SUSPEND);
pm_restore_console();
@@ -259,7 +253,6 @@ int suspend_devices_and_enter(suspend_state_t state)
static void suspend_finish(void)
{
suspend_thaw_processes();
- usermodehelper_enable();
pm_notifier_call_chain(PM_POST_SUSPEND);
pm_restore_console();
}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 33c4329205a..91b0fd021a9 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -12,7 +12,6 @@
#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
-#include <linux/kmod.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
@@ -222,14 +221,8 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
sys_sync();
printk("done.\n");
- error = usermodehelper_disable();
- if (error)
- break;
-
error = freeze_processes();
- if (error)
- usermodehelper_enable();
- else
+ if (!error)
data->frozen = 1;
break;
@@ -238,7 +231,6 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
break;
pm_restore_gfp_mask();
thaw_processes();
- usermodehelper_enable();
data->frozen = 0;
break;