[PATCH 2/3] drm/xe: Do not wake device during a GT reset

[Matthew Brost <matthew.brost@intel.com>]

Waking the device during a GT reset can lead to unintended memory
allocation, which is not allowed since GT resets occur in the reclaim
path. Prevent this by holding a PM reference while a reset is in flight.

Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_gt.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index d8e94fb8b9bd..89808b33d0a8 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -818,17 +818,19 @@ static int gt_reset(struct xe_gt *gt)
 	unsigned int fw_ref;
 	int err;
 
-	if (xe_device_wedged(gt_to_xe(gt)))
-		return -ECANCELED;
+	if (xe_device_wedged(gt_to_xe(gt))) {
+		err = -ECANCELED;
+		goto err_pm_put;
+	}
 
 	/* We only support GT resets with GuC submission */
-	if (!xe_device_uc_enabled(gt_to_xe(gt)))
-		return -ENODEV;
+	if (!xe_device_uc_enabled(gt_to_xe(gt))) {
+		err = -ENODEV;
+		goto err_pm_put;
+	}
 
 	xe_gt_info(gt, "reset started\n");
 
-	xe_pm_runtime_get(gt_to_xe(gt));
-
 	if (xe_fault_inject_gt_reset()) {
 		err = -ECANCELED;
 		goto err_fail;
@@ -875,6 +877,7 @@ static int gt_reset(struct xe_gt *gt)
 	xe_gt_err(gt, "reset failed (%pe)\n", ERR_PTR(err));
 
 	xe_device_declare_wedged(gt_to_xe(gt));
+err_pm_put:
 	xe_pm_runtime_put(gt_to_xe(gt));
 
 	return err;
@@ -896,7 +899,9 @@ void xe_gt_reset_async(struct xe_gt *gt)
 		return;
 
 	xe_gt_info(gt, "reset queued\n");
-	queue_work(gt->ordered_wq, &gt->reset.worker);
+	xe_pm_runtime_get_noresume(gt_to_xe(gt));
+	if (!queue_work(gt->ordered_wq, &gt->reset.worker))
+		xe_pm_runtime_put(gt_to_xe(gt));
 }
 
 void xe_gt_suspend_prepare(struct xe_gt *gt)
-- 
2.34.1