| Message ID | 20170720160748.12856-1-Liviu.Dudau@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jul 20, 2017 at 05:07:48PM +0100, Liviu Dudau wrote: > Explain better when the drm_modeset_acquire_ctx parameter can > be skipped for drm_modeset_lock() call. > > Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Applied, thanks. -Daniel > --- > drivers/gpu/drm/drm_modeset_lock.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c > index 64ef09a6cccb..af4e906c630d 100644 > --- a/drivers/gpu/drm/drm_modeset_lock.c > +++ b/drivers/gpu/drm/drm_modeset_lock.c > @@ -52,7 +52,12 @@ > * drm_modeset_drop_locks(&ctx); > * drm_modeset_acquire_fini(&ctx); > * > - * On top of of these per-object locks using &ww_mutex there's also an overall > + * If all that is needed is a single modeset lock, then the &struct > + * drm_modeset_acquire_ctx is not needed and the locking can be simplified > + * by passing a NULL instead of ctx in the drm_modeset_lock() > + * call and, when done, by calling drm_modeset_unlock(). > + * > + * On top of these per-object locks using &ww_mutex there's also an overall > * &drm_mode_config.mutex, for protecting everything else. Mostly this means > * probe state of connectors, and preventing hotplug add/removal of connectors. > * > @@ -313,11 +318,14 @@ EXPORT_SYMBOL(drm_modeset_lock_init); > * @lock: lock to take > * @ctx: acquire ctx > * > - * If ctx is not NULL, then its ww acquire context is used and the > + * If @ctx is not NULL, then its ww acquire context is used and the > * lock will be tracked by the context and can be released by calling > * drm_modeset_drop_locks(). If -EDEADLK is returned, this means a > * deadlock scenario has been detected and it is an error to attempt > * to take any more locks without first calling drm_modeset_backoff(). > + * > + * If @ctx is NULL then the function call behaves like a normal, > + * non-nesting mutex_lock() call. > */ > int drm_modeset_lock(struct drm_modeset_lock *lock, > struct drm_modeset_acquire_ctx *ctx) > -- > 2.13.2 >
diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c index 64ef09a6cccb..af4e906c630d 100644 --- a/drivers/gpu/drm/drm_modeset_lock.c +++ b/drivers/gpu/drm/drm_modeset_lock.c @@ -52,7 +52,12 @@ * drm_modeset_drop_locks(&ctx); * drm_modeset_acquire_fini(&ctx); * - * On top of of these per-object locks using &ww_mutex there's also an overall + * If all that is needed is a single modeset lock, then the &struct + * drm_modeset_acquire_ctx is not needed and the locking can be simplified + * by passing a NULL instead of ctx in the drm_modeset_lock() + * call and, when done, by calling drm_modeset_unlock(). + * + * On top of these per-object locks using &ww_mutex there's also an overall * &drm_mode_config.mutex, for protecting everything else. Mostly this means * probe state of connectors, and preventing hotplug add/removal of connectors. * @@ -313,11 +318,14 @@ EXPORT_SYMBOL(drm_modeset_lock_init); * @lock: lock to take * @ctx: acquire ctx * - * If ctx is not NULL, then its ww acquire context is used and the + * If @ctx is not NULL, then its ww acquire context is used and the * lock will be tracked by the context and can be released by calling * drm_modeset_drop_locks(). If -EDEADLK is returned, this means a * deadlock scenario has been detected and it is an error to attempt * to take any more locks without first calling drm_modeset_backoff(). + * + * If @ctx is NULL then the function call behaves like a normal, + * non-nesting mutex_lock() call. */ int drm_modeset_lock(struct drm_modeset_lock *lock, struct drm_modeset_acquire_ctx *ctx)
Explain better when the drm_modeset_acquire_ctx parameter can be skipped for drm_modeset_lock() call. Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> --- drivers/gpu/drm/drm_modeset_lock.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)