drm/i915/ttm: audit remaining bo->resource

In the near future TTM will have NULL bo->resource when the object is
initially created, plus after calling into pipeline-gutting. Try to
handle the remaining cases. In practice NULL bo->resource should be
taken to mean swapped-out or purged object.

v2 (Andrzej):
  - Rather make i915_ttm_cpu_maps_iomem() return false with NULL
    resource.

References: 516198d317d8 ("drm/i915: audit bo->resource usage v3")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230130101230.25347-2-matthew.auld@intel.com
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Acked-by: Christian König <ckoenig.leichtzumerken@gmail.com>
Signed-off-by: Christian König <christian.koenig@amd.com>

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 4758f21..341b946 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -472,7 +472,7 @@ static int i915_ttm_shrink(struct drm_i915_gem_object *obj, unsigned int flags)
        struct ttm_placement place = {};
        int ret;
 
-       if (!bo->ttm || bo->resource->mem_type != TTM_PL_SYSTEM)
+       if (!bo->ttm || i915_ttm_cpu_maps_iomem(bo->resource))
                return 0;
 
        GEM_BUG_ON(!i915_tt->is_shmem);
@@ -511,7 +511,13 @@ static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo)
 {
        struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 
-       if (bo->resource && !i915_ttm_is_ghost_object(bo)) {
+       /*
+        * This gets called twice by ttm, so long as we have a ttm resource or
+        * ttm_tt then we can still safely call this. Due to pipeline-gutting,
+        * we maybe have NULL bo->resource, but in that case we should always
+        * have a ttm alive (like if the pages are swapped out).
+        */
+       if ((bo->resource || bo->ttm) && !i915_ttm_is_ghost_object(bo)) {
                __i915_gem_object_pages_fini(obj);
                i915_ttm_free_cached_io_rsgt(obj);
        }

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
index 2a94a99..f8f6bed 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
@@ -98,7 +98,7 @@ static inline bool i915_ttm_gtt_binds_lmem(struct ttm_resource *mem)
 static inline bool i915_ttm_cpu_maps_iomem(struct ttm_resource *mem)
 {
        /* Once / if we support GGTT, this is also false for cached ttm_tts */
-       return mem->mem_type != I915_PL_SYSTEM;
+       return mem && mem->mem_type != I915_PL_SYSTEM;
 }
 
 bool i915_ttm_resource_mappable(struct ttm_resource *res);

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
index 76dd9e5..d030182 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -711,6 +711,10 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
 
        assert_object_held(dst);
        assert_object_held(src);
+
+       if (GEM_WARN_ON(!src_bo->resource || !dst_bo->resource))
+               return -EINVAL;
+
        i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
 
        ret = dma_resv_reserve_fences(src_bo->base.resv, 1);

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
index 7e67742..dfe39c8 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
@@ -53,7 +53,7 @@ static int i915_ttm_backup(struct i915_gem_apply_to_region *apply,
        unsigned int flags;
        int err = 0;
 
-       if (bo->resource->mem_type == I915_PL_SYSTEM || obj->ttm.backup)
+       if (!i915_ttm_cpu_maps_iomem(bo->resource) || obj->ttm.backup)
                return 0;
 
        if (pm_apply->allow_gpu && i915_gem_object_evictable(obj))
@@ -187,7 +187,10 @@ static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
                return err;
 
        /* Content may have been swapped. */
-       err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
+       if (!backup_bo->resource)
+               err = ttm_bo_validate(backup_bo, i915_ttm_sys_placement(), &ctx);
+       if (!err)
+               err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
        if (!err) {
                err = i915_gem_obj_copy_ttm(obj, backup, pm_apply->allow_gpu,
                                            false);