[PATCH 11/64] drm/i915: Disable userptr pread/pwrite support.

[Maarten Lankhorst]

Userptr should not need the kernel for a userspace memcpy, userspace
needs to call memcpy directly.

Specifically, disable i915_gem_pwrite_ioctl() and i915_gem_pread_ioctl().

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>

-- Still needs an ack from relevant userspace that it won't break, but should be good.
---
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 20 ++++++++++++++++++++
 drivers/gpu/drm/i915/i915_gem.c             |  5 +++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 0f9024c62c06..5a19699c2d7e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -700,6 +700,24 @@ i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj)
 	return i915_gem_userptr_init__mmu_notifier(obj, 0);
 }
 
+static int
+i915_gem_userptr_pwrite(struct drm_i915_gem_object *obj,
+			const struct drm_i915_gem_pwrite *args)
+{
+	drm_dbg(obj->base.dev, "pwrite to userptr no longer allowed\n");
+
+	return -EINVAL;
+}
+
+static int
+i915_gem_userptr_pread(struct drm_i915_gem_object *obj,
+		       const struct drm_i915_gem_pread *args)
+{
+	drm_dbg(obj->base.dev, "pread from userptr no longer allowed\n");
+
+	return -EINVAL;
+}
+
 static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
 	.name = "i915_gem_object_userptr",
 	.flags = I915_GEM_OBJECT_IS_SHRINKABLE |
@@ -708,6 +726,8 @@ static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
 	.get_pages = i915_gem_userptr_get_pages,
 	.put_pages = i915_gem_userptr_put_pages,
 	.dmabuf_export = i915_gem_userptr_dmabuf_export,
+	.pwrite = i915_gem_userptr_pwrite,
+	.pread = i915_gem_userptr_pread,
 	.release = i915_gem_userptr_release,
 };
 
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f713299dd84d..993d26597707 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -400,6 +400,11 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data,
 	}
 
 	trace_i915_gem_object_pread(obj, args->offset, args->size);
+	ret = -ENODEV;
+	if (obj->ops->pread)
+		ret = obj->ops->pread(obj, args);
+	if (ret != -ENODEV)
+		goto out;
 
 	ret = -ENODEV;
 	if (obj->ops->pread)
-- 
2.30.0