From 4480ec0c61c184db58f1ce5b918a01607bf963cb Mon Sep 17 00:00:00 2001
From: Matthew Auld <matthew.auld@intel.com>
Date: Mon, 18 Oct 2021 18:45:07 +0100
Subject: drm/i915: mark up internal objects with start_cpu_write
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Git-commit: 3884d8af9b3fcc0c41f04fbd4131be61101d4a4d
Patch-mainline: v5.16-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

While the pages can't be swapped out, they can be discarded by the shrinker.
Normally such objects are marked with __I915_MADV_PURGED, which can't be
unset, and therefore requires a new object. For kernel internal objects
this is not true, since the madv hint is reset for our special volatile
objects, such that we can re-acquire new pages, if so desired, without
needing a new object. As a result we should probably be paranoid here
and put the object back into the CPU domain when discarding the pages,
and also correctly set cache_dirty, if required.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211018174508.2137279-8-matthew.auld@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/gem/i915_gem_internal.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
index e5ae9c06510c..a57a6b7013c2 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
@@ -134,6 +134,8 @@ static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
 	internal_free_pages(pages);
 
 	obj->mm.dirty = false;
+
+	__start_cpu_write(obj);
 }
 
 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
-- 
2.38.1