OMAP: DSS2: OMAPFB: Make lockdep happy
When more than one memory region needs to be lockd at the same time use
the memory region id to fix the order in which the locks are taken. Also
one needs to use the _nested() versions of the locking primitives. The
memory region id can serve as the lock class there as well.
Signed-off-by: Ville Syrjälä <ville.syrjala@nokia.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
diff --git a/drivers/video/omap2/omapfb/omapfb-ioctl.c b/drivers/video/omap2/omapfb/omapfb-ioctl.c
index 3a10146..7975a99 100644
--- a/drivers/video/omap2/omapfb/omapfb-ioctl.c
+++ b/drivers/video/omap2/omapfb/omapfb-ioctl.c
@@ -55,7 +55,7 @@
if (mem_idx >= fbdev->num_fbs)
return NULL;
- return omapfb_get_mem_region(&fbdev->regions[mem_idx]);
+ return &fbdev->regions[mem_idx];
}
static int omapfb_setup_plane(struct fb_info *fbi, struct omapfb_plane_info *pi)
@@ -77,20 +77,30 @@
/* XXX uses only the first overlay */
ovl = ofbi->overlays[0];
- old_rg = omapfb_get_mem_region(ofbi->region);
+ old_rg = ofbi->region;
new_rg = get_mem_region(ofbi, pi->mem_idx);
if (!new_rg) {
r = -EINVAL;
- goto put_old;
+ goto out;
}
+ /* Take the locks in a specific order to keep lockdep happy */
+ if (old_rg->id < new_rg->id) {
+ omapfb_get_mem_region(old_rg);
+ omapfb_get_mem_region(new_rg);
+ } else if (new_rg->id < old_rg->id) {
+ omapfb_get_mem_region(new_rg);
+ omapfb_get_mem_region(old_rg);
+ } else
+ omapfb_get_mem_region(old_rg);
+
if (pi->enabled && !new_rg->size) {
/*
* This plane's memory was freed, can't enable it
* until it's reallocated.
*/
r = -EINVAL;
- goto put_new;
+ goto put_mem;
}
ovl->get_overlay_info(ovl, &old_info);
@@ -135,8 +145,15 @@
if (ovl->manager)
ovl->manager->apply(ovl->manager);
- omapfb_put_mem_region(new_rg);
- omapfb_put_mem_region(old_rg);
+ /* Release the locks in a specific order to keep lockdep happy */
+ if (old_rg->id > new_rg->id) {
+ omapfb_put_mem_region(old_rg);
+ omapfb_put_mem_region(new_rg);
+ } else if (new_rg->id > old_rg->id) {
+ omapfb_put_mem_region(new_rg);
+ omapfb_put_mem_region(old_rg);
+ } else
+ omapfb_put_mem_region(old_rg);
return 0;
@@ -147,10 +164,16 @@
}
ovl->set_overlay_info(ovl, &old_info);
- put_new:
- omapfb_put_mem_region(new_rg);
- put_old:
- omapfb_put_mem_region(old_rg);
+ put_mem:
+ /* Release the locks in a specific order to keep lockdep happy */
+ if (old_rg->id > new_rg->id) {
+ omapfb_put_mem_region(old_rg);
+ omapfb_put_mem_region(new_rg);
+ } else if (new_rg->id > old_rg->id) {
+ omapfb_put_mem_region(new_rg);
+ omapfb_put_mem_region(old_rg);
+ } else
+ omapfb_put_mem_region(old_rg);
out:
dev_err(fbdev->dev, "setup_plane failed\n");
@@ -198,7 +221,7 @@
rg = ofbi->region;
- down_write(&rg->lock);
+ down_write_nested(&rg->lock, rg->id);
if (atomic_read(&rg->map_count)) {
r = -EBUSY;