On 2022-02-10 12:28 a.m., Christoph Hellwig wrote:

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@lst.de

Great! This makes my patch simpler.

Reviewed-by: Logan Gunthorpe logang@deltatee.com

---

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