[PATCH 09/27] mm: generalize the pgmap based page_free infrastructure

From: Christoph Hellwig
Date: Thu Feb 10 2022 - 02:29:28 EST


Key off on the existence of ->page_free to prepare for adding support for
more pgmap types that are device managed and thus need the free callback.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
mm/memremap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memremap.c b/mm/memremap.c
index fef5734d5e4933..e00ffcdba7b632 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -452,7 +452,7 @@ EXPORT_SYMBOL_GPL(get_dev_pagemap);

void free_zone_device_page(struct page *page)
{
- if (WARN_ON_ONCE(!is_device_private_page(page)))
+ if (WARN_ON_ONCE(!page->pgmap->ops || !page->pgmap->ops->page_free))
return;

__ClearPageWaiters(page);
@@ -460,7 +460,7 @@ void free_zone_device_page(struct page *page)
mem_cgroup_uncharge(page_folio(page));

/*
- * When a device_private page is freed, the page->mapping field
+ * When a device managed page is freed, the page->mapping field
* may still contain a (stale) mapping value. For example, the
* lower bits of page->mapping may still identify the page as an
* anonymous page. Ultimately, this entire field is just stale
--
2.30.2