+
+error_unlock:
+ dma_resv_unlock(obj->resv);
+ return ret;
+}
+EXPORT_SYMBOL(drm_exec_prepare_obj);
+
+/**
+ * drm_exec_prepare_array - helper to prepare an array of objects
+ * @exec: the drm_exec object with the state
+ * @objects: array of GEM object to prepare
+ * @num_objects: number of GEM objects in the array
+ * @num_fences: number of fences to reserve on each GEM object
+ *
+ * Prepares all GEM objects in an array, handles contention but
aports on first
+ * error otherwise. Reserves @num_fences on each GEM object
after locking it.
+ *
+ * Returns: -EALREADY when object is already locked, -ENOMEM
when memory
+ * allocation failed and zero for success.
+ */
+int drm_exec_prepare_array(struct drm_exec *exec,
+ struct drm_gem_object **objects,
+ unsigned int num_objects,
+ unsigned int num_fences)
+{
+ int ret;
+
+ for (unsigned int i = 0; i < num_objects; ++i) {
+ ret = drm_exec_prepare_obj(exec, objects[i], num_fences);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_exec_prepare_array);
+
+MODULE_DESCRIPTION("DRM execution context");
+MODULE_LICENSE("Dual MIT/GPL");
diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
new file mode 100644
index 000000000000..b1a5da0509c1
--- /dev/null
+++ b/include/drm/drm_exec.h
@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+
+#ifndef __DRM_EXEC_H__
+#define __DRM_EXEC_H__
+
+#include <linux/ww_mutex.h>
+
+struct drm_gem_object;
+
+/**
+ * enum drm_exec_flags - Execution context flags
+ */
+enum drm_exec_flags {
+ /**
+ * DRM_EXEC_FLAG_INTERRUPTIBLE: Set to true to use
interruptible locking
+ * functions.
+ */
+ DRM_EXEC_FLAG_INTERRUPTIBLE = BIT(0),
+
+ /**
+ * DRM_EXEC_FLAG_ALLOW_DUPLICATES: Set to true to allow
EALREADY errors.
+ */
+ DRM_EXEC_FLAG_ALLOW_DUPLICATES = BIT(1),
+};
+
+/**
+ * struct drm_exec - Execution context
+ */
+struct drm_exec {
+ /**
+ * @flags: Combinations of DRM_EXEC_FLAG_* flags.
+ */
+ u32 flags;
+
+ /**
+ * @ticket: WW ticket used for acquiring locks
+ */
+ struct ww_acquire_ctx ticket;
+
+ /**
+ * @num_objects: number of objects locked
+ */
+ unsigned int num_objects;
+
+ /**
+ * @max_objects: maximum objects in array
+ */
+ unsigned int max_objects;
+
+ /**
+ * @objects: array of the locked objects
+ */
+ struct drm_gem_object **objects;
+
+ /**
+ * @contended: contended GEM object we backed off for
+ */
+ struct drm_gem_object *contended;
+
+ /**
+ * @prelocked: already locked GEM object due to contention
+ */
+ struct drm_gem_object *prelocked;
+};
+
+/**
+ * drm_exec_for_each_locked_object - iterate over all the locked
objects
+ * @exec: drm_exec object
+ * @index: unsigned long index for the iteration
+ * @obj: the current GEM object
+ *
+ * Iterate over all the locked GEM objects inside the drm_exec
object.
+ */
+#define drm_exec_for_each_locked_object(exec, index, obj) \
+ for (index = 0, obj = (exec)->objects[0]; \
+ index < (exec)->num_objects; \
+ ++index, obj = (exec)->objects[index])
+
+/**
+ * drm_exec_until_all_locked - retry objects preparation until
all objects
+ * are locked
+ * @exec: drm_exec object
+ * @expr: expression to be evaluated on each attempt
+ *
+ * This helper tries to prepare objects and if a deadlock is
detected,
+ * rollbacks and retries.
+ *
+ * @expr is typically a function that tries to prepare objects
using
+ * drm_exec_prepare_obj().
+ *
+ * If we take drm_exec_prepare_array() as an example, you should
do:
+ *
+ * ret = drm_exec_until_all_locked(exec,
+ * drm_exec_prepare_array(exec,
+ * objs,
+ * num_objs,
+ * num_fences));
+ * if (ret)
+ * goto error_path;
+ *
+ * ...
+ *
+ * Returns: 0 on success, a negative error code on failure.
+ */
+#define drm_exec_until_all_locked(exec, expr) \
+ ({ \
+ __label__ retry; \
+ int __ret; \
+retry: \
+ __ret = expr; \
+ if ((exec)->contended) { \
+ WARN_ON(__ret != -EDEADLK); \
+ drm_exec_reset(exec); \
+ goto retry; \
+ } \
+ ww_acquire_done(&(exec)->ticket); \
+ __ret; \
+ })
+
+void drm_exec_init(struct drm_exec *exec, u32 flags);
+void drm_exec_fini(struct drm_exec *exec);
+void drm_exec_reset(struct drm_exec *exec);
+int drm_exec_prepare_obj(struct drm_exec *exec, struct
drm_gem_object *obj,
+ unsigned int num_fences);
+int drm_exec_prepare_array(struct drm_exec *exec,
+ struct drm_gem_object **objects,
+ unsigned int num_objects,
+ unsigned int num_fences);
+
+#endif
