drm: Refactor vblank sequence number comparison

Move the repeated (a - b) <= (1 << 23) to its own function.

v2: Catch the '1<<23' inside drm_handle_vblank() as well

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Michel Dänzer <michel@daenzer.net>
Link: http://patchwork.freedesktop.org/patch/msgid/20170322100650.26082-1-chris@chris-wilson.co.uk
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 5078984568b031e2c337c8c44dfdc991624eb2a7..124402270568af685908f2fbf7dbf8721a5890d7 100644 (file)
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -1484,6 +1484,11 @@ int drm_legacy_modeset_ctl(struct drm_device *dev, void *data,
        return 0;
 }
 
+static inline bool vblank_passed(u32 seq, u32 ref)
+{
+       return (seq - ref) <= (1 << 23);
+}
+
 static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
                                  union drm_wait_vblank *vblwait,
                                  struct drm_file *file_priv)
@@ -1534,7 +1539,7 @@ static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
                                      vblwait->request.sequence);
 
        e->event.sequence = vblwait->request.sequence;
-       if ((seq - vblwait->request.sequence) <= (1 << 23)) {
+       if (vblank_passed(seq, vblwait->request.sequence)) {
                drm_vblank_put(dev, pipe);
                send_vblank_event(dev, e, seq, &now);
                vblwait->reply.sequence = seq;
@@ -1624,9 +1629,8 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
        }
 
        if ((flags & _DRM_VBLANK_NEXTONMISS) &&
-           (seq - vblwait->request.sequence) <= (1 << 23)) {
+           vblank_passed(seq, vblwait->request.sequence))
                vblwait->request.sequence = seq + 1;
-       }
 
        if (flags & _DRM_VBLANK_EVENT) {
                /* must hold on to the vblank ref until the event fires
@@ -1639,8 +1643,8 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
                DRM_DEBUG("waiting on vblank count %u, crtc %u\n",
                          vblwait->request.sequence, pipe);
                DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
-                           (drm_vblank_count(dev, pipe) -
-                            vblwait->request.sequence) <= (1 << 23) ||
+                           vblank_passed(drm_vblank_count(dev, pipe),
+                                         vblwait->request.sequence) ||
                            !READ_ONCE(vblank->enabled));
        }
 
@@ -1675,7 +1679,7 @@ static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
        list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
                if (e->pipe != pipe)
                        continue;
-               if ((seq - e->event.sequence) > (1<<23))
+               if (!vblank_passed(seq, e->event.sequence))
                        continue;
 
                DRM_DEBUG("vblank event on %u, current %u\n",