drm/i915: Check domains for userptr on release

When we return pages to the system, we release control over them and
should defensively return them to the CPU write domain so that we catch
any external writes on reacquiring them (e.g. to transparently
swapout/swapin). While we did this defensive clflushing for ordinary
shmem pages, it was forgotten for userptr. Fortunately, userptr objects
are normally cache coherent and so oblivious to the forgotten domain
tracking.

References: a679f58d ("drm/i915: Flush pages on acquisition")
References: 754a2544 ("drm/i915: Skip object locking around a no-op set-domain ioctl")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190331094620.15185-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -308,7 +308,7 @@ static void __start_cpu_write(struct drm_i915_gem_object *obj)
 		obj->cache_dirty = true;
 }
 
-static void
+void
 __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
 				struct sg_table *pages,
 				bool needs_clflush)
@@ -2202,7 +2202,6 @@ i915_gem_object_put_pages_gtt(struct drm_i915_gem_object *obj,
 	struct page *page;
 
 	__i915_gem_object_release_shmem(obj, pages, true);
-
 	i915_gem_gtt_finish_pages(obj, pages);
 
 	if (i915_gem_object_needs_bit17_swizzle(obj))

drivers/gpu/drm/i915/i915_gem_object.h

@@ -502,4 +502,8 @@ void i915_gem_object_set_cache_coherency(struct drm_i915_gem_object *obj,
 					 unsigned int cache_level);
 void i915_gem_object_flush_if_display(struct drm_i915_gem_object *obj);
 
+void __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
+				     struct sg_table *pages,
+				     bool needs_clflush);
+
 #endif

drivers/gpu/drm/i915/i915_gem_userptr.c

@@ -673,9 +673,7 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
 	if (!pages)
 		return;
 
-	if (obj->mm.madv != I915_MADV_WILLNEED)
-		obj->mm.dirty = false;
-
+	__i915_gem_object_release_shmem(obj, pages, true);
 	i915_gem_gtt_finish_pages(obj, pages);
 
 	for_each_sgt_page(page, sgt_iter, pages) {