[Intel-gfx] [PATCH v2 1/3] drm/i915/guc: Allow preempt-client to be NULL

[Chris Wilson]

In the next patch, we may only conditionally allocate the preempt-client
if there is a global preempt context and so we need to be prepared in
case the preempt-client itself is NULL.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski at intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Michel Thierry <michel.thierry at intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
---
 drivers/gpu/drm/i915/intel_guc_submission.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c
index 1f3a8786bbdc..4ea65df05e02 100644
--- a/drivers/gpu/drm/i915/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/intel_guc_submission.c
@@ -832,10 +832,12 @@ static int guc_clients_doorbell_init(struct intel_guc *guc)
 	if (ret)
 		return ret;
 
-	ret = create_doorbell(guc->preempt_client);
-	if (ret) {
-		destroy_doorbell(guc->execbuf_client);
-		return ret;
+	if (guc->preempt_client) {
+		ret = create_doorbell(guc->preempt_client);
+		if (ret) {
+			destroy_doorbell(guc->execbuf_client);
+			return ret;
+		}
 	}
 
 	return 0;
@@ -848,8 +850,11 @@ static void guc_clients_doorbell_fini(struct intel_guc *guc)
 	 * Instead of trying (in vain) to communicate with it, let's just
 	 * cleanup the doorbell HW and our internal state.
 	 */
-	__destroy_doorbell(guc->preempt_client);
-	__update_doorbell_desc(guc->preempt_client, GUC_DOORBELL_INVALID);
+	if (guc->preempt_client) {
+		__destroy_doorbell(guc->preempt_client);
+		__update_doorbell_desc(guc->preempt_client,
+				       GUC_DOORBELL_INVALID);
+	}
 	__destroy_doorbell(guc->execbuf_client);
 	__update_doorbell_desc(guc->execbuf_client, GUC_DOORBELL_INVALID);
 }
@@ -998,10 +1003,11 @@ static void guc_clients_destroy(struct intel_guc *guc)
 {
 	struct intel_guc_client *client;
 
-	client = fetch_and_zero(&guc->execbuf_client);
-	guc_client_free(client);
-
 	client = fetch_and_zero(&guc->preempt_client);
+	if (client)
+		guc_client_free(client);
+
+	client = fetch_and_zero(&guc->execbuf_client);
 	guc_client_free(client);
 }
 
@@ -1160,7 +1166,8 @@ int intel_guc_submission_enable(struct intel_guc *guc)
 	GEM_BUG_ON(!guc->execbuf_client);
 
 	guc_reset_wq(guc->execbuf_client);
-	guc_reset_wq(guc->preempt_client);
+	if (guc->preempt_client)
+		guc_reset_wq(guc->preempt_client);
 
 	err = intel_guc_sample_forcewake(guc);
 	if (err)
-- 
2.15.1