[Intel-gfx] [PATCH] Revert "drm/i915: Disallow pin ioctl completely for kms drivers"

[Chris Wilson]

This reverts commit c211a47c2c28562f8a3fff9e027be1a3ed9e154a.

This causes an unwarranteed API break for existing and active userspace.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c | 90 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 614bc2bc16fe..4a1ca7abd7f9 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4252,6 +4252,96 @@ i915_gem_object_unpin_fence(struct drm_i915_gem_object *obj)
 }
 
 int
+i915_gem_pin_ioctl(struct drm_device *dev, void *data,
+		   struct drm_file *file)
+{
+	struct drm_i915_gem_pin *args = data;
+	struct drm_i915_gem_object *obj;
+	int ret;
+
+	ret = i915_mutex_lock_interruptible(dev);
+	if (ret)
+		return ret;
+
+	obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
+	if (&obj->base == NULL) {
+		ret = -ENOENT;
+		goto unlock;
+	}
+
+	if (obj->madv != I915_MADV_WILLNEED) {
+		DRM_DEBUG("Attempting to pin a purgeable buffer\n");
+		ret = -EFAULT;
+		goto out;
+	}
+
+	if (obj->pin_filp != NULL && obj->pin_filp != file) {
+		DRM_DEBUG("Already pinned in i915_gem_pin_ioctl(): %d\n",
+			  args->handle);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (obj->user_pin_count == ULONG_MAX) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	if (obj->user_pin_count == 0) {
+		ret = i915_gem_obj_ggtt_pin(obj, args->alignment, PIN_MAPPABLE);
+		if (ret)
+			goto out;
+	}
+
+	obj->user_pin_count++;
+	obj->pin_filp = file;
+
+	args->offset = i915_gem_obj_ggtt_offset(obj);
+out:
+	drm_gem_object_unreference(&obj->base);
+unlock:
+	mutex_unlock(&dev->struct_mutex);
+	return ret;
+}
+
+int
+i915_gem_unpin_ioctl(struct drm_device *dev, void *data,
+		     struct drm_file *file)
+{
+	struct drm_i915_gem_pin *args = data;
+	struct drm_i915_gem_object *obj;
+	int ret;
+
+	ret = i915_mutex_lock_interruptible(dev);
+	if (ret)
+		return ret;
+
+	obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
+	if (&obj->base == NULL) {
+		ret = -ENOENT;
+		goto unlock;
+	}
+
+	if (obj->pin_filp != file) {
+		DRM_DEBUG("Not pinned by caller in i915_gem_pin_ioctl(): %d\n",
+			  args->handle);
+		ret = -EINVAL;
+		goto out;
+	}
+	obj->user_pin_count--;
+	if (obj->user_pin_count == 0) {
+		obj->pin_filp = NULL;
+		i915_gem_object_ggtt_unpin(obj);
+	}
+
+out:
+	drm_gem_object_unreference(&obj->base);
+unlock:
+	mutex_unlock(&dev->struct_mutex);
+	return ret;
+}
+
+int
 i915_gem_busy_ioctl(struct drm_device *dev, void *data,
 		    struct drm_file *file)
 {
-- 
2.1.3