On 7/6/26 12:07, Natalie Vock wrote: > 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]>
Reviewed-by: Christian König <[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); >
