[PATCH 6.1 0263/1146] drm/i915: Refactor ttm ghost obj detection

Greg Kroah-Hartman
2022-12-28T15:33:14Z

From: Nirmoy Das <nirmoy.das@intel.com>

[ Upstream commit 6667d78a1123d237d66e34923754ebca97d06d39 ]

Currently i915_ttm_to_gem() returns NULL for ttm ghost
object which makes it unclear when we should add a NULL
check for a caller of i915_ttm_to_gem() as ttm ghost
objects are expected behaviour for certain cases.

Create a separate function to detect ttm ghost object and
use that in places where we expect a ghost obj from ttm.

Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221014131427.21102-1-nirmoy.das@intel.com
Stable-dep-of: 1cacd6894d5f ("drm/i915/dgfx: Grab wakeref at i915_ttm_unmap_virtual")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 21 ++++++++++----------
drivers/gpu/drm/i915/gem/i915_gem_ttm.h | 18 ++++++++++++-----
drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 2 +-
3 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 0d6d640225fc..e08351081375 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -279,7 +279,7 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
struct i915_ttm_tt *i915_tt;
int ret;

- if (!obj)
+ if (i915_ttm_is_ghost_object(bo))
return NULL;

i915_tt = kzalloc(sizeof(*i915_tt), GFP_KERNEL);
@@ -362,7 +362,7 @@ static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);

- if (!obj)
+ if (i915_ttm_is_ghost_object(bo))
return false;

/*
@@ -511,7 +511,7 @@ static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo)
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
intel_wakeref_t wakeref = 0;

- if (bo->resource && likely(obj)) {
+ if (bo->resource && !i915_ttm_is_ghost_object(bo)) {
/* ttm_bo_release() already has dma_resv_lock */
if (i915_ttm_cpu_maps_iomem(bo->resource))
wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm);
@@ -628,7 +628,7 @@ static void i915_ttm_swap_notify(struct ttm_buffer_object *bo)
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
int ret;

- if (!obj)
+ if (i915_ttm_is_ghost_object(bo))
return;

ret = i915_ttm_move_notify(bo);
@@ -661,7 +661,7 @@ static int i915_ttm_io_mem_reserve(struct ttm_device *bdev, struct ttm_resource
struct drm_i915_gem_object *obj = i915_ttm_to_gem(mem->bo);
bool unknown_state;

- if (!obj)
+ if (i915_ttm_is_ghost_object(mem->bo))
return -EINVAL;

if (!kref_get_unless_zero(&obj->base.refcount))
@@ -694,7 +694,7 @@ static unsigned long i915_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
unsigned long base;
unsigned int ofs;

- GEM_BUG_ON(!obj);
+ GEM_BUG_ON(i915_ttm_is_ghost_object(bo));
GEM_WARN_ON(bo->ttm);

base = obj->mm.region->iomap.base - obj->mm.region->region.start;
@@ -994,13 +994,12 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
struct vm_area_struct *area = vmf->vma;
struct ttm_buffer_object *bo = area->vm_private_data;
struct drm_device *dev = bo->base.dev;
- struct drm_i915_gem_object *obj;
+ struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
intel_wakeref_t wakeref = 0;
vm_fault_t ret;
int idx;

- obj = i915_ttm_to_gem(bo);
- if (!obj)
+ if (i915_ttm_is_ghost_object(bo))
return VM_FAULT_SIGBUS;

/* Sanity check that we allow writing into this object */
@@ -1098,7 +1097,7 @@ static void ttm_vm_open(struct vm_area_struct *vma)
struct drm_i915_gem_object *obj =
i915_ttm_to_gem(vma->vm_private_data);

- GEM_BUG_ON(!obj);
+ GEM_BUG_ON(i915_ttm_is_ghost_object(vma->vm_private_data));
i915_gem_object_get(obj);
}

@@ -1107,7 +1106,7 @@ static void ttm_vm_close(struct vm_area_struct *vma)
struct drm_i915_gem_object *obj =
i915_ttm_to_gem(vma->vm_private_data);

- GEM_BUG_ON(!obj);
+ GEM_BUG_ON(i915_ttm_is_ghost_object(vma->vm_private_data));
i915_gem_object_put(obj);
}

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
index e4842b4296fc..2a94a99ef76b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
@@ -27,19 +27,27 @@ i915_gem_to_ttm(struct drm_i915_gem_object *obj)
*/
void i915_ttm_bo_destroy(struct ttm_buffer_object *bo);

+/**
+ * i915_ttm_is_ghost_object - Check if the ttm bo is a ghost object.
+ * @bo: Pointer to the ttm buffer object
+ *
+ * Return: True if the ttm bo is not a i915 object but a ghost ttm object,
+ * False otherwise.
+ */
+static inline bool i915_ttm_is_ghost_object(struct ttm_buffer_object *bo)
+{
+ return bo->destroy != i915_ttm_bo_destroy;
+}
+
/**
* i915_ttm_to_gem - Convert a struct ttm_buffer_object to an embedding
* struct drm_i915_gem_object.
*
- * Return: Pointer to the embedding struct ttm_buffer_object, or NULL
- * if the object was not an i915 ttm object.
+ * Return: Pointer to the embedding struct ttm_buffer_object.
*/
static inline struct drm_i915_gem_object *
i915_ttm_to_gem(struct ttm_buffer_object *bo)
{
- if (bo->destroy != i915_ttm_bo_destroy)
- return NULL;
-
return container_of(bo, struct drm_i915_gem_object, __do_not_access);
}

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 9a7e50534b84..f59f812dc6d2 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -560,7 +560,7 @@ int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
bool clear;
int ret;

- if (GEM_WARN_ON(!obj)) {
+ if (GEM_WARN_ON(i915_ttm_is_ghost_object(bo))) {
ttm_bo_move_null(bo, dst_mem);
return 0;
}
--
2.35.1