drm/i915: move bsd dispatch index somewhere better

Adding stuff at the bottom is really no how this should be done, since
that's the place for ums/dri dungeons.

This was added in

commit a8ebba75b3
Author: Zhao Yakui <yakui.zhao@intel.com>
Date:   Thu Apr 17 10:37:40 2014 +0800

    drm/i915: Use the coarse ping-pong mechanism based on drm fd to dispatch the BSD command on BDW GT3

Also add a note to prevent this from happening again - people really
should be less lazy and take more time to look for a good home of
their new driver-global state.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_dma.c

@@ -1571,7 +1571,6 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	spin_lock_init(&dev_priv->backlight_lock);
 	spin_lock_init(&dev_priv->uncore.lock);
 	spin_lock_init(&dev_priv->mm.object_stat_lock);
-	dev_priv->ring_index = 0;
 	mutex_init(&dev_priv->dpio_lock);
 	mutex_init(&dev_priv->modeset_restore_lock);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -1098,6 +1098,9 @@ struct i915_gem_mm {
 	 */
 	bool busy;
 
+	/* the indicator for dispatch video commands on two BSD rings */
+	int bsd_ring_dispatch_index;
+
 	/** Bit 6 swizzling required for X tiling */
 	uint32_t bit_6_swizzle_x;
 	/** Bit 6 swizzling required for Y tiling */
@@ -1553,8 +1556,11 @@ struct drm_i915_private {
 	struct i915_dri1_state dri1;
 	/* Old ums support infrastructure, same warning applies. */
 	struct i915_ums_state ums;
-	/* the indicator for dispatch video commands on two BSD rings */
-	int ring_index;
+
+	/*
+	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
+	 * will be rejected. Instead look for a better place.
+	 */
 };
 
 static inline struct drm_i915_private *to_i915(const struct drm_device *dev)

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -1027,12 +1027,12 @@ static int gen8_dispatch_bsd_ring(struct drm_device *dev,
 		int ring_id;
 
 		mutex_lock(&dev->struct_mutex);
-		if (dev_priv->ring_index == 0) {
+		if (dev_priv->mm.bsd_ring_dispatch_index == 0) {
 			ring_id = VCS;
-			dev_priv->ring_index = 1;
+			dev_priv->mm.bsd_ring_dispatch_index = 1;
 		} else {
 			ring_id = VCS2;
-			dev_priv->ring_index = 0;
+			dev_priv->mm.bsd_ring_dispatch_index = 0;
 		}
 		file_priv->bsd_ring = &dev_priv->ring[ring_id];
 		mutex_unlock(&dev->struct_mutex);