An upcoming common pattern is to traverse the region object list and perform certain actions on all objects in a region. It's a little tricky to get the list locking right, in particular since a gem object may change region unless it's pinned or the object lock is held.
Define a function that does this for us and that takes an argument that defines the action to be performed on each object.
v3: - Improve structure documentation a bit (Matthew Auld)
Signed-off-by: Thomas Hellström thomas.hellstrom@linux.intel.com Reviewed-by: Matthew Auld matthew.auld@intel.com --- drivers/gpu/drm/i915/gem/i915_gem_region.c | 70 ++++++++++++++++++++++ drivers/gpu/drm/i915/gem/i915_gem_region.h | 37 ++++++++++++ 2 files changed, 107 insertions(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c index 1f557b2178ed..a016ccec36f3 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_region.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c @@ -80,3 +80,73 @@ i915_gem_object_create_region(struct intel_memory_region *mem, i915_gem_object_free(obj); return ERR_PTR(err); } + +/** + * i915_gem_process_region - Iterate over all objects of a region using ops + * to process and optionally skip objects + * @mr: The memory region + * @apply: ops and private data + * + * This function can be used to iterate over the regions object list, + * checking whether to skip objects, and, if not, lock the objects and + * process them using the supplied ops. Note that this function temporarily + * removes objects from the region list while iterating, so that if run + * concurrently with itself may not iterate over all objects. + * + * Return: 0 if successful, negative error code on failure. + */ +int i915_gem_process_region(struct intel_memory_region *mr, + struct i915_gem_apply_to_region *apply) +{ + const struct i915_gem_apply_to_region_ops *ops = apply->ops; + struct drm_i915_gem_object *obj; + struct list_head still_in_list; + int ret = 0; + + /* + * In the future, a non-NULL apply->ww could mean the caller is + * already in a locking transaction and provides its own context. + */ + GEM_WARN_ON(apply->ww); + + INIT_LIST_HEAD(&still_in_list); + mutex_lock(&mr->objects.lock); + for (;;) { + struct i915_gem_ww_ctx ww; + + obj = list_first_entry_or_null(&mr->objects.list, typeof(*obj), + mm.region_link); + if (!obj) + break; + + list_move_tail(&obj->mm.region_link, &still_in_list); + if (!kref_get_unless_zero(&obj->base.refcount)) + continue; + + /* + * Note: Someone else might be migrating the object at this + * point. The object's region is not stable until we lock + * the object. + */ + mutex_unlock(&mr->objects.lock); + apply->ww = &ww; + for_i915_gem_ww(&ww, ret, apply->interruptible) { + ret = i915_gem_object_lock(obj, apply->ww); + if (ret) + continue; + + if (obj->mm.region == mr) + ret = ops->process_obj(apply, obj); + /* Implicit object unlock */ + } + + i915_gem_object_put(obj); + mutex_lock(&mr->objects.lock); + if (ret) + break; + } + list_splice_tail(&still_in_list, &mr->objects.list); + mutex_unlock(&mr->objects.lock); + + return ret; +} diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.h b/drivers/gpu/drm/i915/gem/i915_gem_region.h index 1008e580a89a..fcaa12d657d4 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_region.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_region.h @@ -12,6 +12,41 @@ struct intel_memory_region; struct drm_i915_gem_object; struct sg_table;
+struct i915_gem_apply_to_region; + +/** + * struct i915_gem_apply_to_region_ops - ops to use when iterating over all + * region objects. + */ +struct i915_gem_apply_to_region_ops { + /** + * process_obj - Process the current object + * @apply: Embed this for private data. + * @obj: The current object. + * + * Note that if this function is part of a ww transaction, and + * if returns -EDEADLK for one of the objects, it may be + * rerun for that same object in the same pass. + */ + int (*process_obj)(struct i915_gem_apply_to_region *apply, + struct drm_i915_gem_object *obj); +}; + +/** + * struct i915_gem_apply_to_region - Argument to the struct + * i915_gem_apply_to_region_ops functions. + * @ops: The ops for the operation. + * @ww: Locking context used for the transaction. + * @interruptible: Whether to perform object locking interruptible. + * + * This structure is intended to be embedded in a private struct if needed + */ +struct i915_gem_apply_to_region { + const struct i915_gem_apply_to_region_ops *ops; + struct i915_gem_ww_ctx *ww; + u32 interruptible:1; +}; + void i915_gem_object_init_memory_region(struct drm_i915_gem_object *obj, struct intel_memory_region *mem); void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj); @@ -22,4 +57,6 @@ i915_gem_object_create_region(struct intel_memory_region *mem, resource_size_t page_size, unsigned int flags);
+int i915_gem_process_region(struct intel_memory_region *mr, + struct i915_gem_apply_to_region *apply); #endif