1 files changed, 46 insertions, 57 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 8a707d8bbb1c..f92597c292fe 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -206,11 +206,9 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
                                         struct amdgpu_amdkfd_fence ***ef_list,
                                         unsigned int *ef_count)
 {
-        struct reservation_object_list *fobj;
-        struct reservation_object *resv;
-        unsigned int i = 0, j = 0, k = 0, shared_count;
-        unsigned int count = 0;
-        struct amdgpu_amdkfd_fence **fence_list;
+        struct reservation_object *resv = bo->tbo.resv;
+        struct reservation_object_list *old, *new;
+        unsigned int i, j, k;
 
         if (!ef && !ef_list)
                 return -EINVAL;
@@ -220,76 +218,67 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
                 *ef_count = 0;
         }
 
-        resv = bo->tbo.resv;
-        fobj = reservation_object_get_list(resv);
-
-        if (!fobj)
+        old = reservation_object_get_list(resv);
+        if (!old)
                 return 0;
 
-        preempt_disable();
-        write_seqcount_begin(&resv->seq);
+        new = kmalloc(offsetof(typeof(*new), shared[old->shared_max]),
+                      GFP_KERNEL);
+        if (!new)
+                return -ENOMEM;
 
-        /* Go through all the shared fences in the resevation object. If
-         * ef is specified and it exists in the list, remove it and reduce the
-         * count. If ef is not specified, then get the count of eviction fences
-         * present.
+        /* Go through all the shared fences in the resevation object and sort
+         * the interesting ones to the end of the list.
          */
-        shared_count = fobj->shared_count;
-        for (i = 0; i < shared_count; ++i) {
+        for (i = 0, j = old->shared_count, k = 0; i < old->shared_count; ++i) {
                 struct dma_fence *f;
 
-                f = rcu_dereference_protected(fobj->shared[i],
+                f = rcu_dereference_protected(old->shared[i],
                                               reservation_object_held(resv));
 
-                if (ef) {
-                        if (f->context == ef->base.context) {
-                                dma_fence_put(f);
-                                fobj->shared_count--;
-                        } else {
-                                RCU_INIT_POINTER(fobj->shared[j++], f);
-                        }
-                } else if (to_amdgpu_amdkfd_fence(f))
-                        count++;
+                if ((ef && f->context == ef->base.context) ||
+                    (!ef && to_amdgpu_amdkfd_fence(f)))
+                        RCU_INIT_POINTER(new->shared[--j], f);
+                else
+                        RCU_INIT_POINTER(new->shared[k++], f);
         }
-        write_seqcount_end(&resv->seq);
-        preempt_enable();
-
-        if (ef || !count)
-                return 0;
-
-        /* Alloc memory for count number of eviction fence pointers. Fill the
-         * ef_list array and ef_count
-         */
-        fence_list = kcalloc(count, sizeof(struct amdgpu_amdkfd_fence *),
-                             GFP_KERNEL);
-        if (!fence_list)
-                return -ENOMEM;
+        new->shared_max = old->shared_max;
+        new->shared_count = k;
 
-        preempt_disable();
-        write_seqcount_begin(&resv->seq);
+        if (!ef) {
+                unsigned int count = old->shared_count - j;
 
-        j = 0;
-        for (i = 0; i < shared_count; ++i) {
-                struct dma_fence *f;
-                struct amdgpu_amdkfd_fence *efence;
-
-                f = rcu_dereference_protected(fobj->shared[i],
-                        reservation_object_held(resv));
+                /* Alloc memory for count number of eviction fence pointers.
+                 * Fill the ef_list array and ef_count
+                 */
+                *ef_list = kcalloc(count, sizeof(**ef_list), GFP_KERNEL);
+                *ef_count = count;
 
-                efence = to_amdgpu_amdkfd_fence(f);
-                if (efence) {
-                        fence_list[k++] = efence;
-                        fobj->shared_count--;
-                } else {
-                        RCU_INIT_POINTER(fobj->shared[j++], f);
+                if (!*ef_list) {
+                        kfree(new);
+                        return -ENOMEM;
                 }
         }
 
+        /* Install the new fence list, seqcount provides the barriers */
+        preempt_disable();
+        write_seqcount_begin(&resv->seq);
+        RCU_INIT_POINTER(resv->fence, new);
         write_seqcount_end(&resv->seq);
         preempt_enable();
 
-        *ef_list = fence_list;
-        *ef_count = k;
+        /* Drop the references to the removed fences or move them to ef_list */
+        for (i = j, k = 0; i < old->shared_count; ++i) {
+                struct dma_fence *f;
+
+                f = rcu_dereference_protected(new->shared[i],
+                                              reservation_object_held(resv));
+                if (!ef)
+                        (*ef_list)[k++] = to_amdgpu_amdkfd_fence(f);
+                else
+                        dma_fence_put(f);
+        }
+        kfree_rcu(old, rcu);
 
         return 0;
 }