[PATCH v4 6/8] DSS2: OMAPFB: Convert the memory region locking to rwsem

[ville . syrjala]

From: Ville Syrjälä <ville.syrj...@nokia.com>

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

Signed-off-by: Ville Syrjälä <ville.syrj...@nokia.com>
---
 drivers/video/omap2/omapfb/omapfb-ioctl.c |   10 ++--------
 drivers/video/omap2/omapfb/omapfb-main.c  |    2 +-
 drivers/video/omap2/omapfb/omapfb-sysfs.c |   10 ++--------
 drivers/video/omap2/omapfb/omapfb.h       |   13 +++++--------
 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 f02b1b0..4d5e5af 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 d330032..2bd5b42 100644
--- a/drivers/video/omap2/omapfb/omapfb-main.c
+++ b/drivers/video/omap2/omapfb/omapfb-main.c
@@ -1929,7 +1929,7 @@ 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 6aee279..aa22f7b 100644
--- a/drivers/video/omap2/omapfb/omapfb-sysfs.c
+++ b/drivers/video/omap2/omapfb/omapfb-sysfs.c
@@ -445,13 +445,7 @@ 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;
@@ -483,7 +477,7 @@ 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 db3aef5..195a760 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
-- 
1.6.4.4

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