On Thu, Jun 1, 2023 at 12:40 AM Geert Uytterhoeven [off-list ref] wrote:

Hi Vishal,

On Wed, May 31, 2023 at 11:32 PM Vishal Moola (Oracle)
[off-list ref] wrote:

quoted

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <redacted>

Thanks for your patch!

quoted

--- a/arch/m68k/include/asm/mcf_pgalloc.h
+++ b/arch/m68k/include/asm/mcf_pgalloc.h

@@ -7,20 +7,19 @@

 extern inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-       free_page((unsigned long) pte);
+       pagetable_free(virt_to_ptdesc(pte));
 }

 extern const char bad_pmd_string[];

 extern inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
 {
-       unsigned long page = __get_free_page(GFP_DMA);
+       struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA | __GFP_ZERO, 0);

-       if (!page)
+       if (!ptdesc)
                return NULL;

-       memset((void *)page, 0, PAGE_SIZE);
-       return (pte_t *) (page);
+       return (pte_t *) (ptdesc_address(ptdesc));

No need to cast "void *" when returning a different pointer type.

quoted

 }

 extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)

@@ -35,36 +34,36 @@ extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
                                  unsigned long address)
 {
-       struct page *page = virt_to_page(pgtable);
+       struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);

-       pgtable_pte_page_dtor(page);
-       __free_page(page);
+       pagetable_pte_dtor(ptdesc);
+       pagetable_free(ptdesc);
 }

 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
-       struct page *page = alloc_pages(GFP_DMA, 0);
+       struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA, 0);
        pte_t *pte;

-       if (!page)
+       if (!ptdesc)
                return NULL;
-       if (!pgtable_pte_page_ctor(page)) {
-               __free_page(page);
+       if (!pagetable_pte_ctor(ptdesc)) {
+               pagetable_free(ptdesc);
                return NULL;
        }

-       pte = page_address(page);
-       clear_page(pte);
+       pte = ptdesc_address(ptdesc);
+       pagetable_clear(pte);

        return pte;
 }

 static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
 {
-       struct page *page = virt_to_page(pgtable);
+       struct ptdesc *ptdesc = virt_to_ptdesc(ptdesc);

virt_to_ptdesc(pgtable)

(You can build this using m5475evb_defconfig)

quoted

-       pgtable_pte_page_dtor(page);
-       __free_page(page);
+       pagetable_pte_dtor(ptdesc);
+       pagetable_free(ptdesc);
 }

 /*

@@ -75,16 +74,18 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)

 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-       free_page((unsigned long) pgd);
+       pagetable_free(virt_to_ptdesc(pgd));
 }

 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
        pgd_t *new_pgd;
+       struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA | GFP_NOWARN, 0);

-       new_pgd = (pgd_t *)__get_free_page(GFP_DMA | __GFP_NOWARN);
-       if (!new_pgd)
+       if (!ptdesc)
                return NULL;
+       new_pgd = (pgd_t *) ptdesc_address(ptdesc);

No need to cast "void *" when assigning to a different pointer type.

quoted

+
        memcpy(new_pgd, swapper_pg_dir, PTRS_PER_PGD * sizeof(pgd_t));
        memset(new_pgd, 0, PAGE_OFFSET >> PGDIR_SHIFT);
        return new_pgd;

The rest LGTM.

Thanks so much for the review! I'll make those changes in the next
version.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds