[PATCH v4 8/8] DSS2: OMAPFB: Add some locking debug checks

[ville . syrjala]

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

Trigger WARN_ON() messages from various places in the code in case the
memory region is not currently locked.

Signed-off-by: Ville Syrjälä <ville.syrj...@nokia.com>
---
 drivers/video/omap2/omapfb/omapfb-ioctl.c |    2 ++
 drivers/video/omap2/omapfb/omapfb-main.c  |    6 ++++++
 drivers/video/omap2/omapfb/omapfb-sysfs.c |    2 ++
 drivers/video/omap2/omapfb/omapfb.h       |    3 +++
 4 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/drivers/video/omap2/omapfb/omapfb-ioctl.c 
b/drivers/video/omap2/omapfb/omapfb-ioctl.c
index a3681da..64e70e0 100644
--- a/drivers/video/omap2/omapfb/omapfb-ioctl.c
+++ b/drivers/video/omap2/omapfb/omapfb-ioctl.c
@@ -222,6 +222,7 @@ static int omapfb_setup_mem(struct fb_info *fbi, struct 
omapfb_mem_info *mi)
        rg = ofbi->region;
 
        down_write_nested(&rg->lock, rg->id);
+       atomic_inc(&rg->lock_count);
 
        if (atomic_read(&rg->map_count)) {
                r = -EBUSY;
@@ -252,6 +253,7 @@ static int omapfb_setup_mem(struct fb_info *fbi, struct 
omapfb_mem_info *mi)
        }
 
  out:
+       atomic_dec(&rg->lock_count);
        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 2bd5b42..ac7625d 100644
--- a/drivers/video/omap2/omapfb/omapfb-main.c
+++ b/drivers/video/omap2/omapfb/omapfb-main.c
@@ -667,6 +667,8 @@ int check_fb_var(struct fb_info *fbi, struct 
fb_var_screeninfo *var)
 
        DBG("check_fb_var %d\n", ofbi->id);
 
+       WARN_ON(!atomic_read(&ofbi->region->lock_count));
+
        r = fb_mode_to_dss_mode(var, &mode);
        if (r) {
                DBG("cannot convert var to omap dss mode\n");
@@ -872,6 +874,8 @@ int omapfb_setup_overlay(struct fb_info *fbi, struct 
omap_overlay *ovl,
        int rotation = var->rotate;
        int i;
 
+       WARN_ON(!atomic_read(&ofbi->region->lock_count));
+
        for (i = 0; i < ofbi->num_overlays; i++) {
                if (ovl != ofbi->overlays[i])
                        continue;
@@ -965,6 +969,8 @@ int omapfb_apply_changes(struct fb_info *fbi, int init)
                fill_fb(fbi);
 #endif
 
+       WARN_ON(!atomic_read(&ofbi->region->lock_count));
+
        for (i = 0; i < ofbi->num_overlays; i++) {
                ovl = ofbi->overlays[i];
 
diff --git a/drivers/video/omap2/omapfb/omapfb-sysfs.c 
b/drivers/video/omap2/omapfb/omapfb-sysfs.c
index 1b7cf57..cf2f478 100644
--- a/drivers/video/omap2/omapfb/omapfb-sysfs.c
+++ b/drivers/video/omap2/omapfb/omapfb-sysfs.c
@@ -446,6 +446,7 @@ static ssize_t store_size(struct device *dev, struct 
device_attribute *attr,
        rg = ofbi->region;
 
        down_write_nested(&rg->lock, rg->id);
+       atomic_inc(&rg->lock_count);
 
        if (atomic_read(&rg->map_count)) {
                r = -EBUSY;
@@ -477,6 +478,7 @@ static ssize_t store_size(struct device *dev, struct 
device_attribute *attr,
 
        r = count;
 out:
+       atomic_dec(&rg->lock_count);
        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 676b55d..1305fc9 100644
--- a/drivers/video/omap2/omapfb/omapfb.h
+++ b/drivers/video/omap2/omapfb/omapfb.h
@@ -56,6 +56,7 @@ struct omapfb2_mem_region {
        bool            map;            /* kernel mapped by the driver */
        atomic_t        map_count;
        struct rw_semaphore lock;
+       atomic_t        lock_count;
 };
 
 /* appended to fb_info */
@@ -166,11 +167,13 @@ 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);
 }
 
-- 
1.6.4.4

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