[PATCH v3 3/3] x86/mm/pat: Convert split_large_page() to use ptdescs

Vishal Moola (Oracle)
2026-02-02T17:20:24Z

In order to separately allocate ptdescs from pages, we need all allocation
and free sites to use the appropriate functions.

split_large_page() allocates a page to be used as a page table. This
should be allocating a ptdesc, so convert it.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---
arch/x86/mm/pat/set_memory.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 9f531c87531b..52226679d079 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -1119,9 +1119,10 @@ static void split_set_pte(struct cpa_data *cpa, pte_t *pte, unsigned long pfn,

static int
__split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
- struct page *base)
+ struct ptdesc *ptdesc)
{
unsigned long lpaddr, lpinc, ref_pfn, pfn, pfninc = 1;
+ struct page *base = ptdesc_page(ptdesc);
pte_t *pbase = (pte_t *)page_address(base);
unsigned int i, level;
pgprot_t ref_prot;
@@ -1226,18 +1227,18 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
static int split_large_page(struct cpa_data *cpa, pte_t *kpte,
unsigned long address)
{
- struct page *base;
+ struct ptdesc *ptdesc;

if (!debug_pagealloc_enabled())
spin_unlock(&cpa_lock);
- base = alloc_pages(GFP_KERNEL, 0);
+ ptdesc = pagetable_alloc(GFP_KERNEL, 0);
if (!debug_pagealloc_enabled())
spin_lock(&cpa_lock);
- if (!base)
+ if (!ptdesc)
return -ENOMEM;

- if (__split_large_page(cpa, kpte, address, base))
- __free_page(base);
+ if (__split_large_page(cpa, kpte, address, ptdesc))
+ pagetable_free(ptdesc);

return 0;
}
--
2.52.0