drm/fb-helper: Drop locking from the vsync wait ioctl code

Like with the drm-native vblank wait ioctl we can entirely rely on the
spinlocks in drm_vblank.c, no need at all to take expensive mutexes.
The only reason we had to take mode_config.mutex was to protect the
fbdev helper's data-structures, but that's now done by
fb_helper->lock.

Cc: John Stultz <john.stultz@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170704151833.17304-6-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter 2017-07-04 17:18:25 +02:00
parent bdac4a052a
commit 235d3e4fa1

View file

@ -1328,7 +1328,6 @@ int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
goto unlock;
}
mutex_lock(&dev->mode_config.mutex);
switch (cmd) {
case FBIO_WAITFORVSYNC:
/*
@ -1368,7 +1367,6 @@ int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
}
unlock:
mutex_unlock(&dev->mode_config.mutex);
mutex_unlock(&fb_helper->lock);
return ret;
}