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authorRafael J. Wysocki <rjw@sisk.pl>2011-12-25 23:42:20 +0100
committerRafael J. Wysocki <rjw@sisk.pl>2011-12-25 23:42:20 +0100
commitb7ba68c4a072c9aa8f04b8cf7838b6cd2f48d918 (patch)
treecd8f8029111fc52d06060691fb0325ba2e798e94 /kernel/kmod.c
parent8d274ab7d3d6f23e2bc0e433c8d53acbe60a9773 (diff)
parent90363ddf0a1a4dccfbb8d0c10b8f488bc7fa69f8 (diff)
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Merge branch 'pm-sleep' into pm-for-linus
* pm-sleep: (51 commits) PM: Drop generic_subsys_pm_ops PM / Sleep: Remove forward-only callbacks from AMBA bus type PM / Sleep: Remove forward-only callbacks from platform bus type PM: Run the driver callback directly if the subsystem one is not there PM / Sleep: Make pm_op() and pm_noirq_op() return callback pointers PM / Sleep: Merge internal functions in generic_ops.c PM / Sleep: Simplify generic system suspend callbacks PM / Hibernate: Remove deprecated hibernation snapshot ioctls PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled() PM / Sleep: Recommend [un]lock_system_sleep() over using pm_mutex directly PM / Sleep: Replace mutex_[un]lock(&pm_mutex) with [un]lock_system_sleep() PM / Sleep: Make [un]lock_system_sleep() generic PM / Sleep: Use the freezer_count() functions in [un]lock_system_sleep() APIs PM / Freezer: Remove the "userspace only" constraint from freezer[_do_not]_count() PM / Hibernate: Replace unintuitive 'if' condition in kernel/power/user.c with 'else' Freezer / sunrpc / NFS: don't allow TASK_KILLABLE sleeps to block the freezer PM / Sleep: Unify diagnostic messages from device suspend/resume ACPI / PM: Do not save/restore NVS on Asus K54C/K54HR PM / Hibernate: Remove deprecated hibernation test modes PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl test path ... Conflicts: kernel/kmod.c
Diffstat (limited to 'kernel/kmod.c')
-rw-r--r--kernel/kmod.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 2142687094d3..a0a88543934e 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -34,6 +34,9 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/resource.h>
+#include <linux/notifier.h>
+#include <linux/suspend.h>
+#include <linux/rwsem.h>
#include <asm/uaccess.h>
#include <trace/events/module.h>
@@ -48,6 +51,7 @@ static struct workqueue_struct *khelper_wq;
static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
static DEFINE_SPINLOCK(umh_sysctl_lock);
+static DECLARE_RWSEM(umhelper_sem);
#ifdef CONFIG_MODULES
@@ -273,6 +277,7 @@ static void __call_usermodehelper(struct work_struct *work)
* If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
* (used for preventing user land processes from being created after the user
* 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;
@@ -291,6 +296,18 @@ static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
*/
#define RUNNING_HELPERS_TIMEOUT (5 * HZ)
+void read_lock_usermodehelper(void)
+{
+ down_read(&umhelper_sem);
+}
+EXPORT_SYMBOL_GPL(read_lock_usermodehelper);
+
+void read_unlock_usermodehelper(void)
+{
+ up_read(&umhelper_sem);
+}
+EXPORT_SYMBOL_GPL(read_unlock_usermodehelper);
+
/**
* usermodehelper_disable - prevent new helpers from being started
*/
@@ -298,8 +315,10 @@ int usermodehelper_disable(void)
{
long retval;
+ down_write(&umhelper_sem);
usermodehelper_disabled = 1;
- smp_mb();
+ up_write(&umhelper_sem);
+
/*
* From now on call_usermodehelper_exec() won't start any new
* helpers, so it is sufficient if running_helpers turns out to
@@ -312,7 +331,9 @@ int usermodehelper_disable(void)
if (retval)
return 0;
+ down_write(&umhelper_sem);
usermodehelper_disabled = 0;
+ up_write(&umhelper_sem);
return -EAGAIN;
}
@@ -321,7 +342,9 @@ int usermodehelper_disable(void)
*/
void usermodehelper_enable(void)
{
+ down_write(&umhelper_sem);
usermodehelper_disabled = 0;
+ up_write(&umhelper_sem);
}
/**