drm/i915/gvt: Add error handling for intel_gvt_scan_and_shadow_workload

When an error occurs after shadow_indirect_ctx, this patch is to do the
proper cleanup and rollback to the original states for shadowed indirect
context before the workload is abandoned.

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

v3:
- no return check for clean up functions. (Changbin)

v4:
- expose and reuse the existing release_shadow_wa_ctx. (Zhenyu)

v5:
- move the release function to scheduler.c file. (Zhenyu)

v6:
- move error handling code of intel_gvt_scan_and_shadow_workload
  to here. (Zhenyu)

Signed-off-by: fred gao <fred.gao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/execlist.c

@@ -489,15 +489,6 @@ static void release_shadow_batch_buffer(struct intel_vgpu_workload *workload)
 	}
 }
 
-static void release_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx)
-{
-	if (!wa_ctx->indirect_ctx.obj)
-		return;
-
-	i915_gem_object_unpin_map(wa_ctx->indirect_ctx.obj);
-	i915_gem_object_put(wa_ctx->indirect_ctx.obj);
-}
-
 static int complete_execlist_workload(struct intel_vgpu_workload *workload)
 {
 	struct intel_vgpu *vgpu = workload->vgpu;

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -229,6 +229,15 @@ static int copy_workload_to_ring_buffer(struct intel_vgpu_workload *workload)
 	return 0;
 }
 
+void release_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx)
+{
+	if (!wa_ctx->indirect_ctx.obj)
+		return;
+
+	i915_gem_object_unpin_map(wa_ctx->indirect_ctx.obj);
+	i915_gem_object_put(wa_ctx->indirect_ctx.obj);
+}
+
 /**
  * intel_gvt_scan_and_shadow_workload - audit the workload by scanning and
  * shadow it as well, include ringbuffer,wa_ctx and ctx.
@@ -263,13 +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
@@ -283,18 +292,18 @@ int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload *workload)
 	if (IS_ERR(ring)) {
 		ret = PTR_ERR(ring);
 		gvt_vgpu_err("fail to pin shadow context\n");
-		goto out;
+		goto err_shadow;
 	}
 
 	ret = populate_shadow_context(workload);
 	if (ret)
-		goto out;
+		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 out;
+		goto err_unpin;
 	}
 
 	gvt_dbg_sched("ring id %d get i915 gem request %p\n", ring_id, rq);
@@ -302,10 +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 out;
+		goto err_unpin;
 	workload->shadowed = true;
+	return 0;
 
-out:
+err_unpin:
+	engine->context_unpin(engine, shadow_ctx);
+err_shadow:
+	release_shadow_wa_ctx(&workload->wa_ctx);
+err_scan:
 	return ret;
 }
 

drivers/gpu/drm/i915/gvt/scheduler.h

@@ -140,4 +140,5 @@ int intel_vgpu_init_gvt_context(struct intel_vgpu *vgpu);
 
 void intel_vgpu_clean_gvt_context(struct intel_vgpu *vgpu);
 
+void release_shadow_wa_ctx(struct intel_shadow_wa_ctx *wa_ctx);
 #endif