On 06/09/2021 17:55, Thomas Hellström wrote:
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.
Signed-off-by: Thomas Hellström thomas.hellstrom@linux.intel.com
drivers/gpu/drm/i915/gem/i915_gem_region.c | 70 ++++++++++++++++++++++ drivers/gpu/drm/i915/gem/i915_gem_region.h | 33 ++++++++++ 2 files changed, 103 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..f62195847056 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_region.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_region.h @@ -12,6 +12,37 @@ 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
Should we mention that returning -EDEADLK might result in re-entering the process_obj?
* @apply: Embed this for provate data
s/provate/private
* @obj: The current object.*/- 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 +53,6 @@ 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);