TTM is about to switch to drm_exec for locking objects in the LRU list. When we're done processing the object, we want to unlock it only if the caller doesn't already hold that lock. If DRM_EXEC_IGNORE_DUPLICATES is set on the exec object (which callers may require for unrelated reasons), we have no way of knowing whether the lock is already held.
To remedy this, add a separate helper that forcefully bypasses the IGNORE_DUPLICATES flag for only a single locking operation. Signed-off-by: Natalie Vock <[email protected]> --- drivers/gpu/drm/drm_exec.c | 54 ++++++++++++++++++++++++++++++++++------------ include/drm/drm_exec.h | 2 ++ 2 files changed, 42 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/drm_exec.c b/drivers/gpu/drm/drm_exec.c index 7988f5e7d56a3..ec33ed4a523cc 100644 --- a/drivers/gpu/drm/drm_exec.c +++ b/drivers/gpu/drm/drm_exec.c @@ -190,18 +190,9 @@ static int drm_exec_lock_contended(struct drm_exec *exec) return ret; } -/** - * drm_exec_lock_obj - lock a GEM object for use - * @exec: the drm_exec object with the state - * @obj: the GEM object to lock - * - * Lock a GEM object for use and grab a reference to it. - * - * Returns: -EDEADLK if a contention is detected, -EALREADY when object is - * already locked (can be suppressed by setting the DRM_EXEC_IGNORE_DUPLICATES - * flag), -ENOMEM when memory allocation failed and zero for success. - */ -int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj) +static int __drm_exec_lock_obj(struct drm_exec *exec, + struct drm_gem_object *obj, + bool ignore_duplicates) { int ret; @@ -226,8 +217,7 @@ int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj) return -EDEADLK; } - if (unlikely(ret == -EALREADY) && - exec->flags & DRM_EXEC_IGNORE_DUPLICATES) + if (unlikely(ret == -EALREADY) && ignore_duplicates) return 0; if (unlikely(ret)) @@ -243,8 +233,44 @@ int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj) dma_resv_unlock(obj->resv); return ret; } + +/** + * drm_exec_lock_obj - lock a GEM object for use + * @exec: the drm_exec object with the state + * @obj: the GEM object to lock + * + * Lock a GEM object for use and grab a reference to it. + * + * Returns: -EDEADLK if a contention is detected, -EALREADY when object is + * already locked (can be suppressed by setting the DRM_EXEC_IGNORE_DUPLICATES + * flag), -ENOMEM when memory allocation failed and zero for success. + */ +int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj) +{ + return __drm_exec_lock_obj(exec, obj, + exec->flags & DRM_EXEC_IGNORE_DUPLICATES); +} EXPORT_SYMBOL(drm_exec_lock_obj); +/** + * drm_exec_lock_obj_report_dup - lock a GEM object for use, but always report duplicates + * @exec: the drm_exec object with the state + * @obj: the GEM object to lock + * + * Like drm_exec_lock_obj, lock a GEM object for use and grab a reference to it. + * Unlike drm_exec_lock_obj, DRM_EXEC_IGNORE_DUPLICATES is ignored and duplicates are + * always reported. + * + * Returns: -EDEADLK if a contention is detected, -EALREADY when object is + * already locked, -ENOMEM when memory allocation failed and zero for success. + */ +int drm_exec_lock_obj_report_dup(struct drm_exec *exec, + struct drm_gem_object *obj) +{ + return __drm_exec_lock_obj(exec, obj, false); +} +EXPORT_SYMBOL(drm_exec_lock_obj_report_dup); + /** * drm_exec_unlock_obj - unlock a GEM object in this exec context * @exec: the drm_exec object with the state diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h index 8725ba92ff916..ff80dd2b72240 100644 --- a/include/drm/drm_exec.h +++ b/include/drm/drm_exec.h @@ -176,6 +176,8 @@ void drm_exec_init(struct drm_exec *exec, u32 flags, unsigned nr); void drm_exec_fini(struct drm_exec *exec); bool drm_exec_cleanup(struct drm_exec *exec); int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj); +int drm_exec_lock_obj_report_dup(struct drm_exec *exec, + struct drm_gem_object *obj); void drm_exec_unlock_obj(struct drm_exec *exec, struct drm_gem_object *obj); int drm_exec_prepare_obj(struct drm_exec *exec, struct drm_gem_object *obj, unsigned int num_fences); -- 2.55.0
