PM / Runtime: Return special error code if runtime PM is disabled

Some callers of pm_runtime_get_sync() and other runtime PM helper
functions, scsi_autopm_get_host() and scsi_autopm_get_device() in
particular, need to distinguish error codes returned when runtime PM
is disabled (i.e. power.disable_depth is nonzero for the given
device) from error codes returned in other situations.  For this
reason, make the runtime PM helper functions return -EACCES when
power.disable_depth is nonzero and ensure that this error code
won't be returned by them in any other circumstances.  Modify
scsi_autopm_get_host() and scsi_autopm_get_device() to check the
error code returned by pm_runtime_get_sync() and ignore -EACCES.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 5f5c4236f006..ee99025be6b3 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -135,8 +135,9 @@ static int rpm_check_suspend_allowed(struct device *dev)
 
         if (dev->power.runtime_error)
                 retval = -EINVAL;
-        else if (atomic_read(&dev->power.usage_count) > 0
-            || dev->power.disable_depth > 0)
+        else if (dev->power.disable_depth > 0)
+                retval = -EACCES;
+        else if (atomic_read(&dev->power.usage_count) > 0)
                 retval = -EAGAIN;
         else if (!pm_children_suspended(dev))
                 retval = -EBUSY;
@@ -262,7 +263,7 @@ static int rpm_callback(int (*cb)(struct device *), struct device *dev)
                 spin_lock_irq(&dev->power.lock);
         }
         dev->power.runtime_error = retval;
-        return retval;
+        return retval != -EACCES ? retval : -EIO;
 }
 
 /**
@@ -458,7 +459,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
         if (dev->power.runtime_error)
                 retval = -EINVAL;
         else if (dev->power.disable_depth > 0)
-                retval = -EAGAIN;
+                retval = -EACCES;
         if (retval)
                 goto out;