From f783374c3092cd6d0d7ac2684820350235bb9573 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Wed, 23 Feb 2022 14:35:31 +0100
Subject: drm/amdgpu: install ctx entities with cmpxchg
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Git-commit: d18b8eadd83e3d8d63a45f9479478640dbcfca02
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Since we removed the context lock we need to make sure that not two threads
are trying to install an entity at the same time.
Signed-off-by: Christian König <christian.koenig@amd.com>
Fixes: 461fa7b0ac565e ("drm/amdgpu: remove ctx->lock")
Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index 2d2dceab4c39..5981c7d9bd48 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -205,9 +205,15 @@ static int amdgpu_ctx_init_entity(struct amdgpu_ctx *ctx, u32 hw_ip,
if (r)
goto error_free_entity;
- ctx->entities[hw_ip][ring] = entity;
+ /* It's not an error if we fail to install the new entity */
+ if (cmpxchg(&ctx->entities[hw_ip][ring], NULL, entity))
+ goto cleanup_entity;
+
return 0;
+cleanup_entity:
+ drm_sched_entity_fini(&entity->entity);
+
error_free_entity:
kfree(entity);
--
2.38.1