drm/amdgpu: fix PRT teardown on VM fini v3

v2: new approach fixing this by registering a fence callback for
    all users of the VM on teardown
v3: agd: rebase

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 82 insertions, 26 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 1f1de2115d7d..7e22c3558b29 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1188,22 +1188,31 @@ static void amdgpu_vm_update_prt_state(struct amdgpu_device *adev)
         bool enable;
 
         spin_lock_irqsave(&adev->vm_manager.prt_lock, flags);
-        enable = !!atomic_read(&adev->vm_manager.num_prt_mappings);
+        enable = !!atomic_read(&adev->vm_manager.num_prt_users);
         adev->gart.gart_funcs->set_prt(adev, enable);
         spin_unlock_irqrestore(&adev->vm_manager.prt_lock, flags);
 }
 
 /**
+ * amdgpu_vm_prt_put - add a PRT user
+ */
+static void amdgpu_vm_prt_get(struct amdgpu_device *adev)
+{
+        if (atomic_inc_return(&adev->vm_manager.num_prt_users) == 1)
+                amdgpu_vm_update_prt_state(adev);
+}
+
+/**
  * amdgpu_vm_prt_put - drop a PRT user
  */
 static void amdgpu_vm_prt_put(struct amdgpu_device *adev)
 {
-        if (atomic_dec_return(&adev->vm_manager.num_prt_mappings) == 0)
+        if (atomic_dec_return(&adev->vm_manager.num_prt_users) == 0)
                 amdgpu_vm_update_prt_state(adev);
 }
 
 /**
- * amdgpu_vm_prt - callback for updating the PRT status
+ * amdgpu_vm_prt_cb - callback for updating the PRT status
  */
 static void amdgpu_vm_prt_cb(struct dma_fence *fence, struct dma_fence_cb *_cb)
 {
@@ -1214,6 +1223,29 @@ static void amdgpu_vm_prt_cb(struct dma_fence *fence, struct dma_fence_cb *_cb)
 }
 
 /**
+ * amdgpu_vm_add_prt_cb - add callback for updating the PRT status
+ */
+static void amdgpu_vm_add_prt_cb(struct amdgpu_device *adev,
+                                 struct dma_fence *fence)
+{
+        struct amdgpu_prt_cb *cb = kmalloc(sizeof(struct amdgpu_prt_cb),
+                                           GFP_KERNEL);
+
+        if (!cb) {
+                /* Last resort when we are OOM */
+                if (fence)
+                        dma_fence_wait(fence, false);
+
+                amdgpu_vm_prt_put(cb->adev);
+        } else {
+                cb->adev = adev;
+                if (!fence || dma_fence_add_callback(fence, &cb->cb,
+                                                     amdgpu_vm_prt_cb))
+                        amdgpu_vm_prt_cb(fence, &cb->cb);
+        }
+}
+
+/**
  * amdgpu_vm_free_mapping - free a mapping
  *
  * @adev: amdgpu_device pointer
@@ -1228,24 +1260,47 @@ static void amdgpu_vm_free_mapping(struct amdgpu_device *adev,
                                    struct amdgpu_bo_va_mapping *mapping,
                                    struct dma_fence *fence)
 {
-        if (mapping->flags & AMDGPU_PTE_PRT) {
-                struct amdgpu_prt_cb *cb = kmalloc(sizeof(struct amdgpu_prt_cb),
-                                                   GFP_KERNEL);
+        if (mapping->flags & AMDGPU_PTE_PRT)
+                amdgpu_vm_add_prt_cb(adev, fence);
+        kfree(mapping);
+}
 
-                if (!cb) {
-                        /* Last resort when we are OOM */
-                        if (fence)
-                                dma_fence_wait(fence, false);
+/**
+ * amdgpu_vm_prt_fini - finish all prt mappings
+ *
+ * @adev: amdgpu_device pointer
+ * @vm: requested vm
+ *
+ * Register a cleanup callback to disable PRT support after VM dies.
+ */
+static void amdgpu_vm_prt_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
+{
+        struct reservation_object *resv = vm->page_directory->tbo.resv;
+        struct dma_fence *excl, **shared;
+        unsigned i, shared_count;
+        int r;
 
-                        amdgpu_vm_prt_put(cb->adev);
-                } else {
-                        cb->adev = adev;
-                        if (!fence || dma_fence_add_callback(fence, &cb->cb,
-                                                             amdgpu_vm_prt_cb))
-                                amdgpu_vm_prt_cb(fence, &cb->cb);
-                }
+        r = reservation_object_get_fences_rcu(resv, &excl,
+                                              &shared_count, &shared);
+        if (r) {
+                /* Not enough memory to grab the fence list, as last resort
+                 * block for all the fences to complete.
+                 */
+                reservation_object_wait_timeout_rcu(resv, true, false,
+                                                    MAX_SCHEDULE_TIMEOUT);
+                return;
         }
-        kfree(mapping);
+
+        /* Add a callback for each fence in the reservation object */
+        amdgpu_vm_prt_get(adev);
+        amdgpu_vm_add_prt_cb(adev, excl);
+
+        for (i = 0; i < shared_count; ++i) {
+                amdgpu_vm_prt_get(adev);
+                amdgpu_vm_add_prt_cb(adev, shared[i]);
+        }
+
+        kfree(shared);
 }
 
 /**
@@ -1395,8 +1450,7 @@ int amdgpu_vm_bo_map(struct amdgpu_device *adev,
                 if (!adev->gart.gart_funcs->set_prt)
                         return -EINVAL;
 
-                if (atomic_inc_return(&adev->vm_manager.num_prt_mappings) == 1)
-                        amdgpu_vm_update_prt_state(adev);
+                amdgpu_vm_prt_get(adev);
         }
 
         /* make sure object fit at this offset */
@@ -1699,6 +1753,7 @@ err:
 void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 {
         struct amdgpu_bo_va_mapping *mapping, *tmp;
+        bool prt_fini_called = false;
         int i;
 
         amd_sched_entity_fini(vm->entity.sched, &vm->entity);
@@ -1712,13 +1767,14 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
                 kfree(mapping);
         }
         list_for_each_entry_safe(mapping, tmp, &vm->freed, list) {
-                if (mapping->flags & AMDGPU_PTE_PRT)
-                        continue;
+                if (mapping->flags & AMDGPU_PTE_PRT && !prt_fini_called) {
+                        amdgpu_vm_prt_fini(adev, vm);
+                        prt_fini_called = true;
+                }
 
                 list_del(&mapping->list);
-                kfree(mapping);
+                amdgpu_vm_free_mapping(adev, vm, mapping, NULL);
         }
-        amdgpu_vm_clear_freed(adev, vm);
 
         for (i = 0; i < amdgpu_vm_num_pdes(adev); i++) {
                 struct amdgpu_bo *pt = vm->page_tables[i].bo;
@@ -1765,7 +1821,7 @@ void amdgpu_vm_manager_init(struct amdgpu_device *adev)
         atomic_set(&adev->vm_manager.vm_pte_next_ring, 0);
         atomic64_set(&adev->vm_manager.client_counter, 0);
         spin_lock_init(&adev->vm_manager.prt_lock);
-        atomic_set(&adev->vm_manager.num_prt_mappings, 0);
+        atomic_set(&adev->vm_manager.num_prt_users, 0);
 }
 
 /**
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 1dc5c1064452..57eaf71a5b1c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -164,7 +164,7 @@ struct amdgpu_vm_manager {
 
         /* partial resident texture handling */
         spinlock_t                              prt_lock;
-        atomic_t                                num_prt_mappings;
+        atomic_t                                num_prt_users;
 };
 
 void amdgpu_vm_manager_init(struct amdgpu_device *adev);