struct interval_tree_node it;
struct list_head link;
struct drm_i915_gem_object *obj;
+ bool active;
bool is_linear;
};
obj = mo->obj;
- if (!kref_get_unless_zero(&obj->base.refcount))
+ if (!mo->active ||
+ !kref_get_unless_zero(&obj->base.refcount))
continue;
spin_unlock(&mn->lock);
else
it = interval_tree_iter_first(&mn->objects, start, end);
if (it != NULL) {
- obj = container_of(it, struct i915_mmu_object, it)->obj;
+ struct i915_mmu_object *mo =
+ container_of(it, struct i915_mmu_object, it);
/* The mmu_object is released late when destroying the
* GEM object so it is entirely possible to gain a
* the struct_mutex - and consequently use it after it
* is freed and then double free it.
*/
- if (!kref_get_unless_zero(&obj->base.refcount)) {
- spin_unlock(&mn->lock);
- serial = 0;
- continue;
- }
+ if (mo->active &&
+ kref_get_unless_zero(&mo->obj->base.refcount))
+ obj = mo->obj;
serial = mn->serial;
}
}
static void
+__i915_gem_userptr_set_active(struct drm_i915_gem_object *obj,
+ bool value)
+{
+ /* During mm_invalidate_range we need to cancel any userptr that
+ * overlaps the range being invalidated. Doing so requires the
+ * struct_mutex, and that risks recursion. In order to cause
+ * recursion, the user must alias the userptr address space with
+ * a GTT mmapping (possible with a MAP_FIXED) - then when we have
+ * to invalidate that mmaping, mm_invalidate_range is called with
+ * the userptr address *and* the struct_mutex held. To prevent that
+ * we set a flag under the i915_mmu_notifier spinlock to indicate
+ * whether this object is valid.
+ */
+#if defined(CONFIG_MMU_NOTIFIER)
+ if (obj->userptr.mmu_object == NULL)
+ return;
+
+ spin_lock(&obj->userptr.mmu_object->mn->lock);
+ obj->userptr.mmu_object->active = value;
+ spin_unlock(&obj->userptr.mmu_object->mn->lock);
+#endif
+}
+
+static void
__i915_gem_userptr_get_pages_worker(struct work_struct *_work)
{
struct get_pages_work *work = container_of(_work, typeof(*work), work);
}
}
obj->userptr.work = ERR_PTR(ret);
+ if (ret)
+ __i915_gem_userptr_set_active(obj, false);
}
obj->userptr.workers--;
}
static int
+__i915_gem_userptr_get_pages_schedule(struct drm_i915_gem_object *obj,
+ bool *active)
+{
+ struct get_pages_work *work;
+
+ /* Spawn a worker so that we can acquire the
+ * user pages without holding our mutex. Access
+ * to the user pages requires mmap_sem, and we have
+ * a strict lock ordering of mmap_sem, struct_mutex -
+ * we already hold struct_mutex here and so cannot
+ * call gup without encountering a lock inversion.
+ *
+ * Userspace will keep on repeating the operation
+ * (thanks to EAGAIN) until either we hit the fast
+ * path or the worker completes. If the worker is
+ * cancelled or superseded, the task is still run
+ * but the results ignored. (This leads to
+ * complications that we may have a stray object
+ * refcount that we need to be wary of when
+ * checking for existing objects during creation.)
+ * If the worker encounters an error, it reports
+ * that error back to this function through
+ * obj->userptr.work = ERR_PTR.
+ */
+ if (obj->userptr.workers >= I915_GEM_USERPTR_MAX_WORKERS)
+ return -EAGAIN;
+
+ work = kmalloc(sizeof(*work), GFP_KERNEL);
+ if (work == NULL)
+ return -ENOMEM;
+
+ obj->userptr.work = &work->work;
+ obj->userptr.workers++;
+
+ work->obj = obj;
+ drm_gem_object_reference(&obj->base);
+
+ work->task = current;
+ get_task_struct(work->task);
+
+ INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker);
+ schedule_work(&work->work);
+
+ *active = true;
+ return -EAGAIN;
+}
+
+static int
i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
{
const int num_pages = obj->base.size >> PAGE_SHIFT;
struct page **pvec;
int pinned, ret;
+ bool active;
/* If userspace should engineer that these pages are replaced in
* the vma between us binding this page into the GTT and completion
* to the vma (discard or cloning) which should prevent the more
* egregious cases from causing harm.
*/
+ if (IS_ERR(obj->userptr.work)) {
+ /* active flag will have been dropped already by the worker */
+ ret = PTR_ERR(obj->userptr.work);
+ obj->userptr.work = NULL;
+ return ret;
+ }
+ if (obj->userptr.work)
+ /* active flag should still be held for the pending work */
+ return -EAGAIN;
+
+ /* Let the mmu-notifier know that we have begun and need cancellation */
+ __i915_gem_userptr_set_active(obj, true);
pvec = NULL;
pinned = 0;
GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
if (pvec == NULL) {
pvec = drm_malloc_ab(num_pages, sizeof(struct page *));
- if (pvec == NULL)
+ if (pvec == NULL) {
+ __i915_gem_userptr_set_active(obj, false);
return -ENOMEM;
+ }
}
pinned = __get_user_pages_fast(obj->userptr.ptr, num_pages,
!obj->userptr.read_only, pvec);
}
- if (pinned < num_pages) {
- if (pinned < 0) {
- ret = pinned;
- pinned = 0;
- } else {
- /* Spawn a worker so that we can acquire the
- * user pages without holding our mutex. Access
- * to the user pages requires mmap_sem, and we have
- * a strict lock ordering of mmap_sem, struct_mutex -
- * we already hold struct_mutex here and so cannot
- * call gup without encountering a lock inversion.
- *
- * Userspace will keep on repeating the operation
- * (thanks to EAGAIN) until either we hit the fast
- * path or the worker completes. If the worker is
- * cancelled or superseded, the task is still run
- * but the results ignored. (This leads to
- * complications that we may have a stray object
- * refcount that we need to be wary of when
- * checking for existing objects during creation.)
- * If the worker encounters an error, it reports
- * that error back to this function through
- * obj->userptr.work = ERR_PTR.
- */
- ret = -EAGAIN;
- if (obj->userptr.work == NULL &&
- obj->userptr.workers < I915_GEM_USERPTR_MAX_WORKERS) {
- struct get_pages_work *work;
-
- work = kmalloc(sizeof(*work), GFP_KERNEL);
- if (work != NULL) {
- obj->userptr.work = &work->work;
- obj->userptr.workers++;
-
- work->obj = obj;
- drm_gem_object_reference(&obj->base);
-
- work->task = current;
- get_task_struct(work->task);
-
- INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker);
- schedule_work(&work->work);
- } else
- ret = -ENOMEM;
- } else {
- if (IS_ERR(obj->userptr.work)) {
- ret = PTR_ERR(obj->userptr.work);
- obj->userptr.work = NULL;
- }
- }
- }
- } else {
+
+ active = false;
+ if (pinned < 0)
+ ret = pinned, pinned = 0;
+ else if (pinned < num_pages)
+ ret = __i915_gem_userptr_get_pages_schedule(obj, &active);
+ else
ret = __i915_gem_userptr_set_pages(obj, pvec, num_pages);
- if (ret == 0) {
- obj->userptr.work = NULL;
- pinned = 0;
- }
+ if (ret) {
+ __i915_gem_userptr_set_active(obj, active);
+ release_pages(pvec, pinned, 0);
}
-
- release_pages(pvec, pinned, 0);
drm_free_large(pvec);
return ret;
}
struct sg_page_iter sg_iter;
BUG_ON(obj->userptr.work != NULL);
+ __i915_gem_userptr_set_active(obj, false);
if (obj->madv != I915_MADV_WILLNEED)
obj->dirty = 0;