Revert "OMAPFB: simplify locking"

This reverts commit b41deecbda70067b26a3a7704fdf967a7940935b.

The simpler locking causes huge latencies when two processes use the
omapfb, even if they use different framebuffers.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/video/omap2/omapfb/omapfb.h b/drivers/video/omap2/omapfb/omapfb.h
index 2b5264475ed4..623cd872a367 100644
--- a/drivers/video/omap2/omapfb/omapfb.h
+++ b/drivers/video/omap2/omapfb/omapfb.h
@@ -62,6 +62,8 @@ struct omapfb2_mem_region {
         bool            alloc;          /* allocated by the driver */
         bool            map;            /* kernel mapped by the driver */
         atomic_t        map_count;
+        struct rw_semaphore lock;
+        atomic_t        lock_count;
 };
 
 /* appended to fb_info */
@@ -189,4 +191,18 @@ static inline int omapfb_overlay_enable(struct omap_overlay *ovl,
                 return ovl->disable(ovl);
 }
 
+static inline struct omapfb2_mem_region *
+omapfb_get_mem_region(struct omapfb2_mem_region *rg)
+{
+        down_read_nested(&rg->lock, rg->id);
+        atomic_inc(&rg->lock_count);
+        return rg;
+}
+
+static inline void omapfb_put_mem_region(struct omapfb2_mem_region *rg)
+{
+        atomic_dec(&rg->lock_count);
+        up_read(&rg->lock);
+}
+
 #endif