[PATCH 3/3] drm/xe: Convert xe_pm_runtime_{get, put} to void and protect from recursion

[Rodrigo Vivi]

With mem_access going away and pm_runtime getting called instead,
we need to protect these against recursions.

The put is asynchronous so there's no need to block it. However, for a
proper balance, we need to ensure that the references are taken and
restored regardless of the flow. So, let's convert them all to void and
use some direct linux/pm_runtime functions.

v2: Rebased and update commit message (Matt).

Cc: Matthew Auld <matthew.auld at intel.com>
Reviewed-by: Matthew Auld <matthew.auld at intel.com> #v1
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/xe/xe_pm.c | 25 ++++++++++++++-----------
 drivers/gpu/drm/xe/xe_pm.h |  4 ++--
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 3e13a666fcc7..9fbb6f6c598a 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -408,26 +408,29 @@ int xe_pm_runtime_resume(struct xe_device *xe)
 /**
  * xe_pm_runtime_get - Get a runtime_pm reference and resume synchronously
  * @xe: xe device instance
- *
- * Returns: Any number greater than or equal to 0 for success, negative error
- * code otherwise.
  */
-int xe_pm_runtime_get(struct xe_device *xe)
+void xe_pm_runtime_get(struct xe_device *xe)
 {
-	return pm_runtime_get_sync(xe->drm.dev);
+	pm_runtime_get_noresume(xe->drm.dev);
+
+	if (xe_pm_read_callback_task(xe) == current)
+		return;
+
+	pm_runtime_resume(xe->drm.dev);
 }
 
 /**
  * xe_pm_runtime_put - Put the runtime_pm reference back and mark as idle
  * @xe: xe device instance
- *
- * Returns: Any number greater than or equal to 0 for success, negative error
- * code otherwise.
  */
-int xe_pm_runtime_put(struct xe_device *xe)
+void xe_pm_runtime_put(struct xe_device *xe)
 {
-	pm_runtime_mark_last_busy(xe->drm.dev);
-	return pm_runtime_put(xe->drm.dev);
+	if (xe_pm_read_callback_task(xe) == current) {
+		pm_runtime_put_noidle(xe->drm.dev);
+	} else {
+		pm_runtime_mark_last_busy(xe->drm.dev);
+		pm_runtime_put(xe->drm.dev);
+	}
 }
 
 /**
diff --git a/drivers/gpu/drm/xe/xe_pm.h b/drivers/gpu/drm/xe/xe_pm.h
index 29c20099a3f9..0cb38ca244fe 100644
--- a/drivers/gpu/drm/xe/xe_pm.h
+++ b/drivers/gpu/drm/xe/xe_pm.h
@@ -26,9 +26,9 @@ void xe_pm_runtime_fini(struct xe_device *xe);
 bool xe_pm_runtime_suspended(struct xe_device *xe);
 int xe_pm_runtime_suspend(struct xe_device *xe);
 int xe_pm_runtime_resume(struct xe_device *xe);
-int xe_pm_runtime_get(struct xe_device *xe);
+void xe_pm_runtime_get(struct xe_device *xe);
 int xe_pm_runtime_get_ioctl(struct xe_device *xe);
-int xe_pm_runtime_put(struct xe_device *xe);
+void xe_pm_runtime_put(struct xe_device *xe);
 int xe_pm_runtime_get_if_active(struct xe_device *xe);
 bool xe_pm_runtime_get_if_in_use(struct xe_device *xe);
 bool xe_pm_runtime_resume_and_get(struct xe_device *xe);
-- 
2.43.2