x86/mm: use 'ptdesc' when freeing PMD pages

There are a billion ways to refer to a physical memory address.  One of
the x86 PMD freeing code location chooses to use a 'pte_t *' to point to a
PMD page and then call a PTE-specific freeing function for it.  That's a
bit wonky.

Just use a 'struct ptdesc *' instead.  Its entire purpose is to refer to
page table pages.  It also means being able to remove an explicit cast.

Right now, pte_free_kernel() is a one-liner that calls
pagetable_dtor_free().  Effectively, all this patch does is remove one
superfluous __pa(__va(paddr)) conversion and then call
pagetable_dtor_free() directly instead of through a helper.

Link: https://lkml.kernel.org/r/20251022082635.2462433-5-baolu.lu@linux.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasant Hegde <vasant.hegde@amd.com>
Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yi Lai <yi1.lai@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index ddf248c3ee7dc279454cefc78e7271b6c0f21fa7..2e5ecfdce73c317b53a6ca0d7b85db7f430a2bb3 100644 (file)
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -729,7 +729,7 @@ int pmd_clear_huge(pmd_t *pmd)
 int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 {
        pmd_t *pmd, *pmd_sv;
-       pte_t *pte;
+       struct ptdesc *pt;
        int i;
 
        pmd = pud_pgtable(*pud);
@@ -750,8 +750,8 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 
        for (i = 0; i < PTRS_PER_PMD; i++) {
                if (!pmd_none(pmd_sv[i])) {
-                       pte = (pte_t *)pmd_page_vaddr(pmd_sv[i]);
-                       pte_free_kernel(&init_mm, pte);
+                       pt = page_ptdesc(pmd_page(pmd_sv[i]));
+                       pagetable_dtor_free(pt);
                }
        }
 
@@ -772,15 +772,15 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr)
  */
 int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 {
-       pte_t *pte;
+       struct ptdesc *pt;
 
-       pte = (pte_t *)pmd_page_vaddr(*pmd);
+       pt = page_ptdesc(pmd_page(*pmd));
        pmd_clear(pmd);
 
        /* INVLPG to clear all paging-structure caches */
        flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
 
-       pte_free_kernel(&init_mm, pte);
+       pagetable_dtor_free(pt);
 
        return 1;
 }