From 6eecb67b69af634bbf27279dbef497580d20f9dd Mon Sep 17 00:00:00 2001 From: Zi Yan Date: Sun, 20 Sep 2026 22:27:59 -0400 Subject: [PATCH] xen/grant-table: stop setting PG_private on pages for grant mapping gnttab_alloc_pages() stores xen_page_foreign in page->private. On 32-bit, a pointer to an allocated xen_page_foreign is stored; on 64-bit, xen_page_forCcgn is stored inline. Checking page->private != NULL is enough to tell whether a xen_page_foreign needs to be freed on 32-bit and page->private is zeroed unconditionally on 64-bit. It prepares for a future commit that remove PG_private. No functional change intended. Link: https://lore.kernel.org/20260920-remove-pg_private-v5-3-bb68b6a21869@nvidia.com Signed-off-by: Zi Yan Signed-off-by: Andrew Morton Reviewed-by: David Hildenbrand (Arm) Assisted-by: LLM Cc: Juergen Gross Cc: Stefano Stabellini Cc: Oleksandr Tyshchenko --- drivers/xen/grant-table.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 076c1b0ab87f..f75b5cc71cfc 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -863,10 +863,10 @@ EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames); int gnttab_pages_set_private(int nr_pages, struct page **pages) { +#if BITS_PER_LONG < 64 int i; for (i = 0; i < nr_pages; i++) { -#if BITS_PER_LONG < 64 struct xen_page_foreign *foreign; foreign = kzalloc_obj(*foreign); @@ -874,9 +874,9 @@ int gnttab_pages_set_private(int nr_pages, struct page **pages) return -ENOMEM; set_page_private(pages[i], (unsigned long)foreign); -#endif - SetPagePrivate(pages[i]); } +#endif + /* Data is stored in page->private on 64-bit */ return 0; } @@ -1031,12 +1031,11 @@ void gnttab_pages_clear_private(int nr_pages, struct page **pages) int i; for (i = 0; i < nr_pages; i++) { - if (PagePrivate(pages[i])) { #if BITS_PER_LONG < 64 + if (page_private(pages[i])) kfree((void *)page_private(pages[i])); #endif - ClearPagePrivate(pages[i]); - } + set_page_private(pages[i], 0); } } EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);