4 files changed, 35 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 2c020eafada6..4d22b4b479b8 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1776,6 +1776,7 @@ void i915_reset(struct drm_i915_private *dev_priv)
 	error->reset_count++;
 
 	pr_notice("drm/i915: Resetting chip after gpu hang\n");
+	i915_gem_reset_prepare(dev_priv);
 
 	disable_engines_irq(dev_priv);
 	ret = intel_gpu_reset(dev_priv, ALL_ENGINES);
@@ -1789,7 +1790,7 @@ void i915_reset(struct drm_i915_private *dev_priv)
 		goto error;
 	}
 
-	i915_gem_reset(dev_priv);
+	i915_gem_reset_finish(dev_priv);
 	intel_overlay_reset(dev_priv);
 
 	/* Ok, now get things going again... */
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 0ea63d6acf4c..7b436621d038 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3334,7 +3334,8 @@ static inline u32 i915_reset_count(struct i915_gpu_error *error)
 	return READ_ONCE(error->reset_count);
 }
 
-void i915_gem_reset(struct drm_i915_private *dev_priv);
+void i915_gem_reset_prepare(struct drm_i915_private *dev_priv);
+void i915_gem_reset_finish(struct drm_i915_private *dev_priv);
 void i915_gem_set_wedged(struct drm_i915_private *dev_priv);
 void i915_gem_clflush_object(struct drm_i915_gem_object *obj, bool force);
 int __must_check i915_gem_init(struct drm_i915_private *dev_priv);
@@ -3418,6 +3419,7 @@ i915_gem_object_ggtt_offset(struct drm_i915_gem_object *o,
 int __must_check i915_vma_get_fence(struct i915_vma *vma);
 int __must_check i915_vma_put_fence(struct i915_vma *vma);
 
+void i915_gem_revoke_fences(struct drm_i915_private *dev_priv);
 void i915_gem_restore_fences(struct drm_i915_private *dev_priv);
 
 void i915_gem_detect_bit_6_swizzle(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d8760acf8001..37107448a42b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2726,6 +2726,11 @@ static void reset_request(struct drm_i915_gem_request *request)
 	memset(vaddr + head, 0, request->postfix - head);
 }
 
+void i915_gem_reset_prepare(struct drm_i915_private *dev_priv)
+{
+	i915_gem_revoke_fences(dev_priv);
+}
+
 static void i915_gem_reset_engine(struct intel_engine_cs *engine)
 {
 	struct drm_i915_gem_request *request;
@@ -2791,7 +2796,7 @@ static void i915_gem_reset_engine(struct intel_engine_cs *engine)
 	spin_unlock_irqrestore(&engine->timeline->lock, flags);
 }
 
-void i915_gem_reset(struct drm_i915_private *dev_priv)
+void i915_gem_reset_finish(struct drm_i915_private *dev_priv)
 {
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
diff --git a/drivers/gpu/drm/i915/i915_gem_fence_reg.c b/drivers/gpu/drm/i915/i915_gem_fence_reg.c
index e03983973252..775059e19ab9 100644
--- a/drivers/gpu/drm/i915/i915_gem_fence_reg.c
+++ b/drivers/gpu/drm/i915/i915_gem_fence_reg.c
@@ -367,6 +367,30 @@ i915_vma_get_fence(struct i915_vma *vma)
 }
 
 /**
+ * i915_gem_revoke_fences - revoke fence state
+ * @dev_priv: i915 device private
+ *
+ * Removes all GTT mmappings via the fence registers. This forces any user
+ * of the fence to reacquire that fence before continuing with their access.
+ * One use is during GPU reset where the fence register is lost and we need to
+ * revoke concurrent userspace access via GTT mmaps until the hardware has been
+ * reset and the fence registers have been restored.
+ */
+void i915_gem_revoke_fences(struct drm_i915_private *dev_priv)
+{
+	int i;
+
+	lockdep_assert_held(&dev_priv->drm.struct_mutex);
+
+	for (i = 0; i < dev_priv->num_fence_regs; i++) {
+		struct drm_i915_fence_reg *fence = &dev_priv->fence_regs[i];
+
+		if (fence->vma)
+			i915_gem_release_mmap(fence->vma->obj);
+	}
+}
+
+/**
  * i915_gem_restore_fences - restore fence state
  * @dev_priv: i915 device private
  *