On Thu, 15 Jul 2021 at 23:39, Jason Ekstrand <jason@xxxxxxxxxxxxxx> wrote:
>
> Since we don't allow changing the set of regions after creation, we can
> make ext_set_placements() build up the region set directly in the
> create_ext and assign it to the object later. This is similar to what
> we did for contexts with the proto-context only simpler because there's
> no funny object shuffling. This will be used in the next patch to allow
> us to de-duplicate a bunch of code. Also, since we know the maximum
> number of regions up-front, we can use a fixed-size temporary array for
> the regions. This simplifies memory management a bit for this new
> delayed approach.
>
> Signed-off-by: Jason Ekstrand <jason@xxxxxxxxxxxxxx>
I think the plan was to have each extension directly hang/apply their
state on the vanilla/proto object, or at least that was the idea
behind: 357814f878f9 ("drm/i915: rework gem_create flow for upcoming
extensions"). A previous version looked similar to this IIRC.
> ---
> drivers/gpu/drm/i915/gem/i915_gem_create.c | 75 +++++++++++++---------
> 1 file changed, 45 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> index 51f92e4b1a69d..391c8c4a12172 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> @@ -27,10 +27,13 @@ static u32 object_max_page_size(struct drm_i915_gem_object *obj)
> return max_page_size;
> }
>
> -static void object_set_placements(struct drm_i915_gem_object *obj,
> - struct intel_memory_region **placements,
> - unsigned int n_placements)
> +static int object_set_placements(struct drm_i915_gem_object *obj,
> + struct intel_memory_region **placements,
> + unsigned int n_placements)
> {
> + struct intel_memory_region **arr;
> + unsigned int i;
> +
> GEM_BUG_ON(!n_placements);
>
> /*
> @@ -44,9 +47,20 @@ static void object_set_placements(struct drm_i915_gem_object *obj,
> obj->mm.placements = &i915->mm.regions[mr->id];
> obj->mm.n_placements = 1;
> } else {
> - obj->mm.placements = placements;
> + arr = kmalloc_array(n_placements,
> + sizeof(struct intel_memory_region *),
> + GFP_KERNEL);
> + if (!arr)
> + return -ENOMEM;
> +
> + for (i = 0; i < n_placements; i++)
> + arr[i] = placements[i];
> +
> + obj->mm.placements = arr;
> obj->mm.n_placements = n_placements;
> }
> +
> + return 0;
> }
>
> static int i915_gem_publish(struct drm_i915_gem_object *obj,
> @@ -148,7 +162,9 @@ i915_gem_dumb_create(struct drm_file *file,
> return -ENOMEM;
>
> mr = intel_memory_region_by_type(to_i915(dev), mem_type);
> - object_set_placements(obj, &mr, 1);
> + ret = object_set_placements(obj, &mr, 1);
> + if (ret)
> + goto object_free;
>
> ret = i915_gem_setup(obj, args->size);
> if (ret)
> @@ -184,7 +200,9 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
> return -ENOMEM;
>
> mr = intel_memory_region_by_type(i915, INTEL_MEMORY_SYSTEM);
> - object_set_placements(obj, &mr, 1);
> + ret = object_set_placements(obj, &mr, 1);
> + if (ret)
> + goto object_free;
>
> ret = i915_gem_setup(obj, args->size);
> if (ret)
> @@ -197,9 +215,12 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
> return ret;
> }
>
> +#define MAX_N_PLACEMENTS = (INTEL_REGION_UNKNOWN + 1)
Unused?
> +
> struct create_ext {
> struct drm_i915_private *i915;
> - struct drm_i915_gem_object *vanilla_object;
> + struct intel_memory_region *placements[INTEL_REGION_UNKNOWN];
> + unsigned int n_placements;
> };
>
> static void repr_placements(char *buf, size_t size,
> @@ -230,8 +251,7 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> struct drm_i915_private *i915 = ext_data->i915;
> struct drm_i915_gem_memory_class_instance __user *uregions =
> u64_to_user_ptr(args->regions);
> - struct drm_i915_gem_object *obj = ext_data->vanilla_object;
> - struct intel_memory_region **placements;
> + struct intel_memory_region *placements[INTEL_REGION_UNKNOWN];
> u32 mask;
> int i, ret = 0;
>
> @@ -245,6 +265,8 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> ret = -EINVAL;
> }
>
> + BUILD_BUG_ON(ARRAY_SIZE(i915->mm.regions) != ARRAY_SIZE(placements));
> + BUILD_BUG_ON(ARRAY_SIZE(ext_data->placements) != ARRAY_SIZE(placements));
> if (args->num_regions > ARRAY_SIZE(i915->mm.regions)) {
> drm_dbg(&i915->drm, "num_regions is too large\n");
> ret = -EINVAL;
> @@ -253,12 +275,6 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> if (ret)
> return ret;
>
> - placements = kmalloc_array(args->num_regions,
> - sizeof(struct intel_memory_region *),
> - GFP_KERNEL);
> - if (!placements)
> - return -ENOMEM;
> -
> mask = 0;
> for (i = 0; i < args->num_regions; i++) {
> struct drm_i915_gem_memory_class_instance region;
> @@ -293,14 +309,13 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> ++uregions;
> }
>
> - if (obj->mm.placements) {
> + if (ext_data->n_placements) {
> ret = -EINVAL;
> goto out_dump;
> }
>
> - object_set_placements(obj, placements, args->num_regions);
> - if (args->num_regions == 1)
> - kfree(placements);
> + for (i = 0; i < args->num_regions; i++)
> + ext_data->placements[i] = placements[i];
kfree(placements) is still in the error unwind?
