[v4.4,STABLE] PM / Domains: defer setting dev->pm_domain until genpd->attach_dev succeeds if present

Message ID 1501063655-30208-1-git-send-email-sudeep.holla@arm.com
State New
Headers show

Commit Message

Sudeep Holla July 26, 2017, 10:07 a.m.
commit 975e83cfb8dc16e7a2fdc58188c77c0c605876c2 upstream.

If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach
may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets
the PM domain for the device unconditionally.

When subsequent attempts are made to call genpd_dev_pm_attach, it may
return -EEXISTS checking dev->pm_domain without re-attempting to call
attach_dev or power_on.

platform_drv_probe then attempts to call drv->probe as the return value
-EEXIST != -EPROBE_DEFER, which may end up in a situation where the
device is accessed without it's power domain switched on.

Fixes: f104e1e5ef57 (PM / Domains: Re-order initialization of generic_pm_domain_data)
Cc: 4.4+ <stable@vger.kernel.org> # v4.4+
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

---
 drivers/base/power/domain.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--
2.7.4

Comments

Greg KH Aug. 3, 2017, 10:35 p.m. | #1
On Wed, Jul 26, 2017 at 11:07:35AM +0100, Sudeep Holla wrote:
> commit 975e83cfb8dc16e7a2fdc58188c77c0c605876c2 upstream.

> 

> If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach

> may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets

> the PM domain for the device unconditionally.

> 

> When subsequent attempts are made to call genpd_dev_pm_attach, it may

> return -EEXISTS checking dev->pm_domain without re-attempting to call

> attach_dev or power_on.

> 

> platform_drv_probe then attempts to call drv->probe as the return value

> -EEXIST != -EPROBE_DEFER, which may end up in a situation where the

> device is accessed without it's power domain switched on.

> 

> Fixes: f104e1e5ef57 (PM / Domains: Re-order initialization of generic_pm_domain_data)

> Cc: 4.4+ <stable@vger.kernel.org> # v4.4+

> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ---

>  drivers/base/power/domain.c | 6 ++++--

>  1 file changed, 4 insertions(+), 2 deletions(-)


Now applied, thanks.

greg k-h

Patch

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index a48824deabc5..da5718e7fbb7 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1188,7 +1188,6 @@  static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
 	}

 	dev->power.subsys_data->domain_data = &gpd_data->base;
-	dev->pm_domain = &genpd->domain;

 	spin_unlock_irq(&dev->power.lock);

@@ -1207,7 +1206,6 @@  static void genpd_free_dev_data(struct device *dev,
 {
 	spin_lock_irq(&dev->power.lock);

-	dev->pm_domain = NULL;
 	dev->power.subsys_data->domain_data = NULL;

 	spin_unlock_irq(&dev->power.lock);
@@ -1248,6 +1246,8 @@  int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (ret)
 		goto out;

+	dev->pm_domain = &genpd->domain;
+
 	genpd->device_count++;
 	genpd->max_off_time_changed = true;

@@ -1299,6 +1299,8 @@  int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 	if (genpd->detach_dev)
 		genpd->detach_dev(genpd, dev);

+	dev->pm_domain = NULL;
+
 	list_del_init(&pdd->list_node);

 	mutex_unlock(&genpd->lock);