[PATCH] drm/amdgpu:resolv deadlock between reset and cs_ioctl

[Monk Liu]

need to unreserve ttm bo before "cs_add_fence" and "entity_push_job"
otherwise there will be deadlock between "recover_vram_from_shadow"
and previous two routines on the ttm bo's resv lock.

Change-Id: I9c18b677e474ce5b45a9cc24da3fa255d77b3d44
Signed-off-by: Monk Liu <Monk.Liu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 35 ++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index c1f1ae9..823ac12 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -736,26 +736,12 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser *p)
 /**
  * cs_parser_fini() - clean parser states
  * @parser:	parser structure holding parsing context.
- * @error:	error number
- *
- * If error is set than unvalidate buffer, otherwise just free memory
- * used by parsing context.
  **/
-static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error, bool backoff)
+static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser)
 {
 	struct amdgpu_fpriv *fpriv = parser->filp->driver_priv;
 	unsigned i;
 
-	if (!error) {
-		amdgpu_vm_move_pt_bos_in_lru(parser->adev, &fpriv->vm);
-
-		ttm_eu_fence_buffer_objects(&parser->ticket,
-					    &parser->validated,
-					    parser->fence);
-	} else if (backoff) {
-		ttm_eu_backoff_reservation(&parser->ticket,
-					   &parser->validated);
-	}
 	fence_put(parser->fence);
 
 	if (parser->ctx)
@@ -1075,6 +1061,16 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 	job->owner = p->filp;
 	job->fence_ctx = entity->fence_context;
 	p->fence = fence_get(&job->base.s_fence->finished);
+
+	/* hook sched fence to all BOs' reservation in validated list
+	 * and unreserve them.
+	 *
+	 * we unreserve at here is because otherwise
+	 * there'll be deadlock between ctx_add_fence/sched_entity_push_job
+	 * and gpu_reset routine's recover_bo_from_shadow on PD/PTEs' ttm bo lock
+	 */
+	ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
+
 	r = amdgpu_ctx_add_fence(p->ctx, ring, p->fence, &seq);
 	if (r) {
 		fence_put(p->fence);
@@ -1095,6 +1091,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 {
 	struct amdgpu_device *adev = dev->dev_private;
 	union drm_amdgpu_cs *cs = data;
+	struct amdgpu_fpriv *fpriv;
 	struct amdgpu_cs_parser parser = {};
 	bool reserved_buffers = false;
 	int i, r;
@@ -1104,6 +1101,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 
 	parser.adev = adev;
 	parser.filp = filp;
+	fpriv = filp->driver_priv;
 
 	r = amdgpu_cs_parser_init(&parser, data);
 	if (r) {
@@ -1141,7 +1139,12 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 	r = amdgpu_cs_submit(&parser, cs);
 
 out:
-	amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
+	if (!r)
+		amdgpu_vm_move_pt_bos_in_lru(parser.adev, &fpriv->vm);
+	else if (reserved_buffers)
+		ttm_eu_backoff_reservation(&parser.ticket, &parser.validated);
+
+	amdgpu_cs_parser_fini(&parser);
 	return r;
 }
 
-- 
2.7.4