[PATCH 5/6] drm/i915/gvt: Refine error handling in dispatch_workload

[fred gao]

When an error occurs in dispatch_workload, this patch is to do the
proper cleanup and rollback to the original states before the workload
is abandoned.

v2:
- split the mixed several error paths for better review. (Zhenyu)

v3:
- original PTR_ERR(cs) is good and code cleanup. (Zhenyu)

v4:
- reuse the existing i915_add_request for error handling. (Zhenyu)

Signed-off-by: fred gao <fred.gao at intel.com>
---
 drivers/gpu/drm/i915/gvt/scheduler.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 2846a82..f5f14d9 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -272,13 +272,13 @@ int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload *workload)
 
 	ret = intel_gvt_scan_and_shadow_ringbuffer(workload);
 	if (ret)
-		goto out;
+		goto err_scan;
 
 	if ((workload->ring_id == RCS) &&
 	    (workload->wa_ctx.indirect_ctx.size != 0)) {
 		ret = intel_gvt_scan_and_shadow_wa_ctx(&workload->wa_ctx);
 		if (ret)
-			goto out;
+			goto err_scan;
 	}
 
 	/* pin shadow context by gvt even the shadow context will be pinned
@@ -297,13 +297,13 @@ int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload *workload)
 
 	ret = populate_shadow_context(workload);
 	if (ret)
-		goto err_shadow;
+		goto err_unpin;
 
 	rq = i915_gem_request_alloc(dev_priv->engine[ring_id], shadow_ctx);
 	if (IS_ERR(rq)) {
 		gvt_vgpu_err("fail to allocate gem request\n");
 		ret = PTR_ERR(rq);
-		goto err_shadow;
+		goto err_unpin;
 	}
 
 	gvt_dbg_sched("ring id %d get i915 gem request %p\n", ring_id, rq);
@@ -311,13 +311,15 @@ int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload *workload)
 	workload->req = i915_gem_request_get(rq);
 	ret = copy_workload_to_ring_buffer(workload);
 	if (ret)
-		goto err_shadow;
+		goto err_unpin;
 	workload->shadowed = true;
 	return 0;
 
+err_unpin:
+	engine->context_unpin(engine, shadow_ctx);
 err_shadow:
 	release_shadow_wa_ctx(&workload->wa_ctx);
-out:
+err_scan:
 	return ret;
 }
 
@@ -334,15 +336,24 @@ static int dispatch_workload(struct intel_vgpu_workload *workload)
 
 	ret = intel_gvt_scan_and_shadow_workload(workload);
 	if (ret)
-		goto out;
+		goto err_scan;
 
 	if (workload->prepare) {
 		ret = workload->prepare(workload);
 		if (ret)
-			goto out;
+			goto err_shadow;
 	}
 
-out:
+err_shadow:
+	if (ret) {
+		struct i915_gem_context *shadow_ctx;
+		struct intel_engine_cs *engine = dev_priv->engine[ring_id];
+
+		shadow_ctx = workload->vgpu->shadow_ctx;
+		engine->context_unpin(engine, shadow_ctx);
+		release_shadow_wa_ctx(&workload->wa_ctx);
+	}
+err_scan:
 	if (ret)
 		workload->status = ret;
 
-- 
2.7.4