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[Public]<br>
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Acked-by: Alex Deucher <alexander.deucher@amd.com><br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> amd-gfx <amd-gfx-bounces@lists.freedesktop.org> on behalf of Christian König <ckoenig.leichtzumerken@gmail.com><br>
<b>Sent:</b> Wednesday, February 23, 2022 8:38 AM<br>
<b>To:</b> amd-gfx@lists.freedesktop.org <amd-gfx@lists.freedesktop.org><br>
<b>Cc:</b> Koenig, Christian <Christian.Koenig@amd.com>; Xue, Ken <Ken.Xue@amd.com><br>
<b>Subject:</b> [PATCH] drm/amdgpu: install ctx entities with cmpxchg</font>
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<div class="PlainText">Since we removed the context lock we need to make sure that not two threads<br>
are trying to install an entity at the same time.<br>
<br>
Signed-off-by: Christian König <christian.koenig@amd.com><br>
Fixes: e68efb27647f ("drm/amdgpu: remove ctx->lock")<br>
---<br>
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 8 +++++++-<br>
1 file changed, 7 insertions(+), 1 deletion(-)<br>
<br>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c<br>
index f522b52725e4..16eb1ee600ed 100644<br>
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c<br>
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c<br>
@@ -204,9 +204,15 @@ static int amdgpu_ctx_init_entity(struct amdgpu_ctx *ctx, u32 hw_ip,<br>
if (r)<br>
goto error_free_entity;<br>
<br>
- ctx->entities[hw_ip][ring] = entity;<br>
+ /* It's not an error if we fail to install the new entity */<br>
+ if (cmpxchg(&ctx->entities[hw_ip][ring], NULL, entity))<br>
+ goto cleanup_entity;<br>
+<br>
return 0;<br>
<br>
+cleanup_entity:<br>
+ drm_sched_entity_fini(&entity->entity);<br>
+<br>
error_free_entity:<br>
kfree(entity);<br>
<br>
-- <br>
2.25.1<br>
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