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authormochel@digitalimplant.org <mochel@digitalimplant.org>2005-03-21 10:41:04 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2005-06-20 15:15:12 -0700
commitaf70316af182f4716cc5eec7e0d27fc731d164bd (patch)
tree22fa4732c8270db8fd3f681355cd83e4b8088847 /drivers/base/power
parenteb51b65005737b777e0709683b061d5f82aefd97 (diff)
[PATCH] Add a semaphore to struct device to synchronize calls to its driver.
This adds a per-device semaphore that is taken before every call from the core to a driver method. This prevents e.g. simultaneous calls to the ->suspend() or ->resume() and ->probe() or ->release(), potentially saving a whole lot of headaches. It also moves us a step closer to removing the bus rwsem, since it protects the fields in struct device that are modified by the core. Signed-off-by: Patrick Mochel <mochel@digitalimplant.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/base/power')
-rw-r--r--drivers/base/power/resume.c8
-rw-r--r--drivers/base/power/suspend.c3
2 files changed, 8 insertions, 3 deletions
diff --git a/drivers/base/power/resume.c b/drivers/base/power/resume.c
index 26468971ef5..bdd96b03b88 100644
--- a/drivers/base/power/resume.c
+++ b/drivers/base/power/resume.c
@@ -22,6 +22,9 @@ extern int sysdev_resume(void);
int resume_device(struct device * dev)
{
+ int error = 0;
+
+ down(&dev->sem);
if (dev->power.pm_parent
&& dev->power.pm_parent->power.power_state) {
dev_err(dev, "PM: resume from %d, parent %s still %d\n",
@@ -31,9 +34,10 @@ int resume_device(struct device * dev)
}
if (dev->bus && dev->bus->resume) {
dev_dbg(dev,"resuming\n");
- return dev->bus->resume(dev);
+ error = dev->bus->resume(dev);
}
- return 0;
+ up(&dev->sem);
+ return error;
}
diff --git a/drivers/base/power/suspend.c b/drivers/base/power/suspend.c
index 0ec44ef840b..807e13fb205 100644
--- a/drivers/base/power/suspend.c
+++ b/drivers/base/power/suspend.c
@@ -39,6 +39,7 @@ int suspend_device(struct device * dev, pm_message_t state)
{
int error = 0;
+ down(&dev->sem);
if (dev->power.power_state) {
dev_dbg(dev, "PM: suspend %d-->%d\n",
dev->power.power_state, state);
@@ -58,7 +59,7 @@ int suspend_device(struct device * dev, pm_message_t state)
dev_dbg(dev, "suspending\n");
error = dev->bus->suspend(dev, state);
}
-
+ up(&dev->sem);
return error;
}