drm: don't call the vblank tasklet with irqs disabled.

If a specific tasklet shares data with irq context,
it needs to take a private irq-blocking spinlock within
the tasklet itself.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 12 insertions, 8 deletions

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 089c015c01d1..53f0e5af1cc8 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -400,27 +400,31 @@ static void drm_locked_tasklet_func(unsigned long data)
 {
         struct drm_device *dev = (struct drm_device *)data;
         unsigned long irqflags;
-
+        void (*tasklet_func)(struct drm_device *);
+        
         spin_lock_irqsave(&dev->tasklet_lock, irqflags);
+        tasklet_func = dev->locked_tasklet_func;
+        spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
 
-        if (!dev->locked_tasklet_func ||
+        if (!tasklet_func ||
             !drm_lock_take(&dev->lock,
                            DRM_KERNEL_CONTEXT)) {
-                spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
                 return;
         }
 
         dev->lock.lock_time = jiffies;
         atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
 
-        dev->locked_tasklet_func(dev);
+        spin_lock_irqsave(&dev->tasklet_lock, irqflags);
+        tasklet_func = dev->locked_tasklet_func;
+        dev->locked_tasklet_func = NULL;
+        spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
+        
+        if (tasklet_func != NULL)
+                tasklet_func(dev);
 
         drm_lock_free(&dev->lock,
                       DRM_KERNEL_CONTEXT);
-
-        dev->locked_tasklet_func = NULL;
-
-        spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
 }
 
 /**