Re: [Intel-gfx] [PATCH 1/2] drm/ttm: prevent moving of pinned BOs

Tue, 24 Jan 2023 01:51:43 -0800 

Am 11.01.23 um 14:17 schrieb Matthew Auld:

On Wed, 11 Jan 2023 at 11:43, Christian König
<ckoenig.leichtzumer...@gmail.com> wrote:

We have checks for this in the individual drivers move callback, but
it's probably better to generally forbit that on a higher level.

Also stops exporting ttm_resource_compat() since that's not necessary
any more after removing the extra checks in vmwgfx.

Signed-off-by: Christian König <christian.koe...@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c |  4 ----
  drivers/gpu/drm/nouveau/nouveau_bo.c    |  3 ---
  drivers/gpu/drm/radeon/radeon_ttm.c     |  4 ----
  drivers/gpu/drm/ttm/ttm_bo.c            | 20 ++++++++++++--------
  drivers/gpu/drm/ttm/ttm_resource.c      |  1 -
  drivers/gpu/drm/vmwgfx/vmwgfx_bo.c      | 19 ++-----------------
  6 files changed, 14 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 068c2d8495fd..677cd7d91687 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -466,11 +466,7 @@ static int amdgpu_bo_move(struct ttm_buffer_object *bo, 
bool evict,
                         return r;
         }

-       /* Can't move a pinned BO */
         abo = ttm_to_amdgpu_bo(bo);
-       if (WARN_ON_ONCE(abo->tbo.pin_count > 0))
-               return -EINVAL;
-
         adev = amdgpu_ttm_adev(bo->bdev);

         if (!old_mem || (old_mem->mem_type == TTM_PL_SYSTEM &&
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c 
b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 288eebc70a67..c2ec91cc845d 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -1015,9 +1015,6 @@ nouveau_bo_move(struct ttm_buffer_object *bo, bool evict,
         if (ret)
                 goto out_ntfy;

-       if (nvbo->bo.pin_count)
-               NV_WARN(drm, "Moving pinned object %p!\n", nvbo);
-
         if (drm->client.device.info.family < NV_DEVICE_INFO_V0_TESLA) {
                 ret = nouveau_bo_vm_bind(bo, new_reg, &new_tile);
                 if (ret)
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c 
b/drivers/gpu/drm/radeon/radeon_ttm.c
index 1e8e287e113c..67075c85f847 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -211,11 +211,7 @@ static int radeon_bo_move(struct ttm_buffer_object *bo, 
bool evict,
         if (r)
                 return r;

-       /* Can't move a pinned BO */
         rbo = container_of(bo, struct radeon_bo, tbo);
-       if (WARN_ON_ONCE(rbo->tbo.pin_count > 0))
-               return -EINVAL;
-
         rdev = radeon_get_rdev(bo->bdev);
         if (old_mem->mem_type == TTM_PL_SYSTEM && bo->ttm == NULL) {
                 ttm_bo_move_null(bo, new_mem);
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 326a3d13a829..9baccb2f6e99 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -894,14 +894,18 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
         if (!placement->num_placement && !placement->num_busy_placement)
                 return ttm_bo_pipeline_gutting(bo);

-       /*
-        * Check whether we need to move buffer.
-        */
-       if (!bo->resource || !ttm_resource_compat(bo->resource, placement)) {
-               ret = ttm_bo_move_buffer(bo, placement, ctx);
-               if (ret)
-                       return ret;
-       }
+       /* Check whether we need to move buffer. */
+       if (bo->resource && ttm_resource_compat(bo->resource, placement))
+               return 0;

Note this now skips the tt create below (intentional?). I think i915
needed that, since it creates a dummy system resource initially for
all objects, and then relies on ZERO_ALLOC being set for certain
objects to know if the memory needs to be cleared or not when later
doing the dummy -> vram. Thoughts?
That's unproblematic. On initial allocation bo->resource is NULL so we never branch out here. 

Christian.




+
+       /* Moving of pinned BOs is forbidden */
+       if (bo->pin_count)
+               return -EINVAL;
+
+       ret = ttm_bo_move_buffer(bo, placement, ctx);
+       if (ret)
+               return ret;
+
         /*
          * We might need to add a TTM.
          */
diff --git a/drivers/gpu/drm/ttm/ttm_resource.c 
b/drivers/gpu/drm/ttm/ttm_resource.c
index b8a826a24fb2..7333f7a87a2f 100644
--- a/drivers/gpu/drm/ttm/ttm_resource.c
+++ b/drivers/gpu/drm/ttm/ttm_resource.c
@@ -361,7 +361,6 @@ bool ttm_resource_compat(struct ttm_resource *res,

         return false;
  }
-EXPORT_SYMBOL(ttm_resource_compat);

  void ttm_resource_set_bo(struct ttm_resource *res,
                          struct ttm_buffer_object *bo)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c 
b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
index 321c551784a1..dbcef460c452 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
@@ -87,12 +87,7 @@ int vmw_bo_pin_in_placement(struct vmw_private *dev_priv,
         if (unlikely(ret != 0))
                 goto err;

-       if (buf->base.pin_count > 0)
-               ret = ttm_resource_compat(bo->resource, placement)
-                       ? 0 : -EINVAL;
-       else
-               ret = ttm_bo_validate(bo, placement, &ctx);
-
+       ret = ttm_bo_validate(bo, placement, &ctx);
         if (!ret)
                 vmw_bo_pin_reserved(buf, true);

@@ -128,12 +123,6 @@ int vmw_bo_pin_in_vram_or_gmr(struct vmw_private *dev_priv,
         if (unlikely(ret != 0))
                 goto err;

-       if (buf->base.pin_count > 0) {
-               ret = ttm_resource_compat(bo->resource, &vmw_vram_gmr_placement)
-                       ? 0 : -EINVAL;
-               goto out_unreserve;
-       }
-
         ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, &ctx);
         if (likely(ret == 0) || ret == -ERESTARTSYS)
                 goto out_unreserve;
@@ -218,11 +207,7 @@ int vmw_bo_pin_in_start_of_vram(struct vmw_private 
*dev_priv,
                 (void) ttm_bo_validate(bo, &vmw_sys_placement, &ctx);
         }

-       if (buf->base.pin_count > 0)
-               ret = ttm_resource_compat(bo->resource, &placement)
-                       ? 0 : -EINVAL;
-       else
-               ret = ttm_bo_validate(bo, &placement, &ctx);
+       ret = ttm_bo_validate(bo, &placement, &ctx);

         /* For some reason we didn't end up at the start of vram */
         WARN_ON(ret == 0 && bo->resource->start != 0);
--
2.34.1

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