drm/amdgpu: Free user pages if amdgpu_cs_parser_bos failed

Otherwise userspace resubmit the BOs again will trigger kernel WARNING
and fail the command submission.
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Tested-by: Robert Święcki <robert@swiecki.net>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c

@@ -550,7 +550,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 		if (r) {
 			kvfree(e->user_pages);
 			e->user_pages = NULL;
-			return r;
+			goto out_free_user_pages;
 		}
 
 		for (i = 0; i < bo->tbo.ttm->num_pages; i++) {
@@ -567,7 +567,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 	if (unlikely(r != 0)) {
 		if (r != -ERESTARTSYS)
 			DRM_ERROR("ttm_eu_reserve_buffers failed.\n");
-		goto out;
+		goto out_free_user_pages;
 	}
 
 	amdgpu_bo_list_for_each_entry(e, p->bo_list) {
@@ -649,7 +649,19 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
 		}
 		ttm_eu_backoff_reservation(&p->ticket, &p->validated);
 	}
-out:
+
+out_free_user_pages:
+	if (r) {
+		amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
+			struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
+
+			if (!e->user_pages)
+				continue;
+			amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
+			kvfree(e->user_pages);
+			e->user_pages = NULL;
+		}
+	}
 	return r;
 }