OMAP: DSS2: OMAPFB: Convert the memory region locking to rwsem

R/W semaphore is a good fit for the memory region locking pattern.
So use it.

Signed-off-by: Ville Syrjälä <ville.syrjala@nokia.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>

4 files changed, 10 insertions, 25 deletions

diff --git a/drivers/video/omap2/omapfb/omapfb-ioctl.c b/drivers/video/omap2/omapfb/omapfb-ioctl.c
index 69bcbfca47f6..3a10146dc120 100644
--- a/drivers/video/omap2/omapfb/omapfb-ioctl.c
+++ b/drivers/video/omap2/omapfb/omapfb-ioctl.c
@@ -198,13 +198,7 @@ static int omapfb_setup_mem(struct fb_info *fbi, struct omapfb_mem_info *mi)
 
         rg = ofbi->region;
 
-        /* FIXME probably should be a rwsem ... */
-        mutex_lock(&rg->mtx);
-        while (rg->ref) {
-                mutex_unlock(&rg->mtx);
-                schedule();
-                mutex_lock(&rg->mtx);
-        }
+        down_write(&rg->lock);
 
         if (atomic_read(&rg->map_count)) {
                 r = -EBUSY;
@@ -235,7 +229,7 @@ static int omapfb_setup_mem(struct fb_info *fbi, struct omapfb_mem_info *mi)
         }
 
  out:
-        mutex_unlock(&rg->mtx);
+        up_write(&rg->lock);
 
         return r;
 }
diff --git a/drivers/video/omap2/omapfb/omapfb-main.c b/drivers/video/omap2/omapfb/omapfb-main.c
index eb4338bbaa2b..a3f72ba79958 100644
--- a/drivers/video/omap2/omapfb/omapfb-main.c
+++ b/drivers/video/omap2/omapfb/omapfb-main.c
@@ -1930,7 +1930,7 @@ static int omapfb_create_framebuffers(struct omapfb2_device *fbdev)
 
                 ofbi->region = &fbdev->regions[i];
                 ofbi->region->id = i;
-                mutex_init(&ofbi->region->mtx);
+                init_rwsem(&ofbi->region->lock);
 
                 /* assign these early, so that fb alloc can use them */
                 ofbi->rotation_type = def_vrfb ? OMAP_DSS_ROT_VRFB :
diff --git a/drivers/video/omap2/omapfb/omapfb-sysfs.c b/drivers/video/omap2/omapfb/omapfb-sysfs.c
index 74c11b243100..724b760404f2 100644
--- a/drivers/video/omap2/omapfb/omapfb-sysfs.c
+++ b/drivers/video/omap2/omapfb/omapfb-sysfs.c
@@ -452,13 +452,7 @@ static ssize_t store_size(struct device *dev, struct device_attribute *attr,
 
         rg = ofbi->region;
 
-        /* FIXME probably should be a rwsem ... */
-        mutex_lock(&rg->mtx);
-        while (rg->ref) {
-                mutex_unlock(&rg->mtx);
-                schedule();
-                mutex_lock(&rg->mtx);
-        }
+        down_write(&rg->lock);
 
         if (atomic_read(&rg->map_count)) {
                 r = -EBUSY;
@@ -490,7 +484,7 @@ static ssize_t store_size(struct device *dev, struct device_attribute *attr,
 
         r = count;
 out:
-        mutex_unlock(&rg->mtx);
+        up_write(&rg->lock);
 
         unlock_fb_info(fbi);
 
diff --git a/drivers/video/omap2/omapfb/omapfb.h b/drivers/video/omap2/omapfb/omapfb.h
index db3aef5172c5..195a760eef54 100644
--- a/drivers/video/omap2/omapfb/omapfb.h
+++ b/drivers/video/omap2/omapfb/omapfb.h
@@ -27,6 +27,8 @@
 #define DEBUG
 #endif
 
+#include <linux/rwsem.h>
+
 #include <plat/display.h>
 
 #ifdef DEBUG
@@ -52,9 +54,8 @@ struct omapfb2_mem_region {
         u8              type;           /* OMAPFB_PLANE_MEM_* */
         bool            alloc;          /* allocated by the driver */
         bool            map;            /* kernel mapped by the driver */
-        struct mutex    mtx;
-        unsigned int    ref;
         atomic_t        map_count;
+        struct rw_semaphore lock;
 };
 
 /* appended to fb_info */
@@ -164,17 +165,13 @@ static inline int omapfb_overlay_enable(struct omap_overlay *ovl,
 static inline struct omapfb2_mem_region *
 omapfb_get_mem_region(struct omapfb2_mem_region *rg)
 {
-        mutex_lock(&rg->mtx);
-        rg->ref++;
-        mutex_unlock(&rg->mtx);
+        down_read(&rg->lock);
         return rg;
 }
 
 static inline void omapfb_put_mem_region(struct omapfb2_mem_region *rg)
 {
-        mutex_lock(&rg->mtx);
-        rg->ref--;
-        mutex_unlock(&rg->mtx);
+        up_read(&rg->lock);
 }
 
 #endif