[PATCH v3 4/5] drm/amdgpu: validate the eviction fence before attaching/detaching

[Prike Liang]

Before the user queue BOs resume workqueue is scheduled;
there's no valid eviction fence to attach the gem obj.
For this case, it doesn't need to attach/detach the eviction
fence. Also, it needs to unlock the bo first before returning
from the eviction fence attached error.

Signed-off-by: Prike Liang <prike.li...@amd.com>
---
 .../drm/amd/amdgpu/amdgpu_eviction_fence.c    | 22 +++++++++++++++----
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c       |  3 ++-
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
index 7a5f02ef45a7..242bfb91c4f7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eviction_fence.c
@@ -196,16 +196,22 @@ int amdgpu_eviction_fence_attach(struct 
amdgpu_eviction_fence_mgr *evf_mgr,
        if (!resv)
                return 0;
 
+       /* Validate the eviction fence first */
+       spin_lock(&evf_mgr->ev_fence_lock);
+       ev_fence = evf_mgr->ev_fence;
+       if (!ev_fence ||
+                       dma_fence_is_signaled(&evf_mgr->ev_fence->base)) {
+               spin_unlock(&evf_mgr->ev_fence_lock);
+               return 0;
+       }
+
        ret = dma_resv_reserve_fences(resv, 1);
        if (ret) {
                DRM_DEBUG_DRIVER("Failed to resv fence space\n");
                return ret;
        }
 
-       spin_lock(&evf_mgr->ev_fence_lock);
-       ev_fence = evf_mgr->ev_fence;
-       if (ev_fence)
-               dma_resv_add_fence(resv, &ev_fence->base, 
DMA_RESV_USAGE_BOOKKEEP);
+       dma_resv_add_fence(resv, &ev_fence->base, DMA_RESV_USAGE_BOOKKEEP);
        spin_unlock(&evf_mgr->ev_fence_lock);
 
        return 0;
@@ -216,6 +222,14 @@ void amdgpu_eviction_fence_detach(struct 
amdgpu_eviction_fence_mgr *evf_mgr,
 {
        struct dma_fence *stub = dma_fence_get_stub();
 
+       spin_lock(&evf_mgr->ev_fence_lock);
+       if (!evf_mgr->ev_fence ||
+                       dma_fence_is_signaled(&evf_mgr->ev_fence->base)) {
+               spin_unlock(&evf_mgr->ev_fence_lock);
+               return;
+       }
+       spin_unlock(&evf_mgr->ev_fence_lock);
+
        dma_resv_replace_fences(bo->tbo.base.resv, evf_mgr->ev_fence_ctx,
                                stub, DMA_RESV_USAGE_BOOKKEEP);
        dma_fence_put(stub);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index f03fc3cf4d50..86779dc817b9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -294,10 +294,11 @@ static int amdgpu_gem_object_open(struct drm_gem_object 
*obj,
        else
                ++bo_va->ref_count;
 
-       /* attach gfx eviction fence */
+       /* attach gfx the validated eviction fence */
        r = amdgpu_eviction_fence_attach(&fpriv->evf_mgr, abo);
        if (r) {
                DRM_DEBUG_DRIVER("Failed to attach eviction fence to BO\n");
+               amdgpu_bo_unreserve(abo);
                return r;
        }
 
-- 
2.34.1