[PATCH] 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.

For D3cold, the TTM migration helpers will call for the job execution.
Jobs execution will be protected by direct runtime_pm calls, but they
cannot be called again if we are already at a runtime suspend/resume
transaction when evicting/restoring memory for D3Cold. So, we will check
for the xe_pm_read_callback_task.

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.

Cc: Matthew Auld <matthew.auld at intel.com>
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 b5511e3c3153..3664480b21ba 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 7f5884babb29..fdc2a49c1a1f 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);
 void xe_pm_assert_unbounded_bridge(struct xe_device *xe);
 int xe_pm_set_vram_threshold(struct xe_device *xe, u32 threshold);
-- 
2.43.2