[RFC PATCH v2 20/20] mm: Remove CONFIG_ARCH_HAS_HUGEPD

Christophe Leroy
2024-05-17T19:01:50Z

powerpc was the only user of CONFIG_ARCH_HAS_HUGEPD and doesn't
use it anymore, so remove all related code.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/mm/hugetlbpage.c | 1 -
include/linux/hugetlb.h | 6 --
mm/Kconfig | 10 ----
mm/gup.c | 105 +---------------------------------
mm/pagewalk.c | 57 ++----------------
5 files changed, 5 insertions(+), 174 deletions(-)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 6fad89d7bff3..1df9e4fa1001 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -79,7 +79,6 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
return NULL;
return (pte_t *)pmd;
}
-#endif

#ifdef CONFIG_PPC_BOOK3S_64
/*
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index d9c5d9daadc5..c020e3bdf62b 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -20,12 +20,6 @@ struct user_struct;
struct mmu_gather;
struct node;

-#ifndef CONFIG_ARCH_HAS_HUGEPD
-typedef struct { unsigned long pd; } hugepd_t;
-#define is_hugepd(hugepd) (0)
-#define __hugepd(x) ((hugepd_t) { (x) })
-#endif
-
void free_huge_folio(struct folio *folio);

#ifdef CONFIG_HUGETLB_PAGE
diff --git a/mm/Kconfig b/mm/Kconfig
index b1448aa81e15..a52f8e3224fb 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1114,16 +1114,6 @@ config DMAPOOL_TEST
config ARCH_HAS_PTE_SPECIAL
bool

-#
-# Some architectures require a special hugepage directory format that is
-# required to support multiple hugepage sizes. For example a4fe3ce76
-# "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
-# introduced it on powerpc. This allows for a more flexible hugepage
-# pagetable layouts.
-#
-config ARCH_HAS_HUGEPD
- bool
-
config MAPPING_DIRTY_HELPERS
bool

diff --git a/mm/gup.c b/mm/gup.c
index 86b5105b82a1..95f121223f04 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2790,89 +2790,6 @@ static int record_subpages(struct page *page, unsigned long addr,
return nr;
}

-#ifdef CONFIG_ARCH_HAS_HUGEPD
-static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
- unsigned long sz)
-{
- unsigned long __boundary = (addr + sz) & ~(sz-1);
- return (__boundary - 1 < end - 1) ? __boundary : end;
-}
-
-static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
-{
- unsigned long pte_end;
- struct page *page;
- struct folio *folio;
- pte_t pte;
- int refs;
-
- pte_end = (addr + sz) & ~(sz-1);
- if (pte_end < end)
- end = pte_end;
-
- pte = huge_ptep_get(NULL, addr, ptep);
-
- if (!pte_access_permitted(pte, flags & FOLL_WRITE))
- return 0;
-
- /* hugepages are never "special" */
- VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
-
- page = nth_page(pte_page(pte), (addr & (sz - 1)) >> PAGE_SHIFT);
- refs = record_subpages(page, addr, end, pages + *nr);
-
- folio = try_grab_folio(page, refs, flags);
- if (!folio)
- return 0;
-
- if (unlikely(pte_val(pte) != pte_val(ptep_get(ptep)))) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
-
- if (!folio_fast_pin_allowed(folio, flags)) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
-
- if (!pte_write(pte) && gup_must_unshare(NULL, flags, &folio->page)) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
-
- *nr += refs;
- folio_set_referenced(folio);
- return 1;
-}
-
-static int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
- unsigned int pdshift, unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
-{
- pte_t *ptep;
- unsigned long sz = 1UL << hugepd_shift(hugepd);
- unsigned long next;
-
- ptep = hugepte_offset(hugepd, addr, pdshift);
- do {
- next = hugepte_addr_end(addr, end, sz);
- if (!gup_hugepte(ptep, sz, addr, end, flags, pages, nr))
- return 0;
- } while (ptep++, addr = next, addr != end);
-
- return 1;
-}
-#else
-static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
- unsigned int pdshift, unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
-{
- return 0;
-}
-#endif /* CONFIG_ARCH_HAS_HUGEPD */
-
static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
@@ -3026,14 +2943,6 @@ static int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, unsigned lo
pages, nr))
return 0;

- } else if (unlikely(is_hugepd(__hugepd(pmd_val(pmd))))) {
- /*
- * architecture have different format for hugetlbfs
- * pmd format and THP pmd format
- */
- if (!gup_huge_pd(__hugepd(pmd_val(pmd)), addr,
- PMD_SHIFT, next, flags, pages, nr))
- return 0;
} else if (!gup_pte_range(pmd, pmdp, addr, next, flags, pages, nr))
return 0;
} while (pmdp++, addr = next, addr != end);
@@ -3058,10 +2967,6 @@ static int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, unsigned lo
if (!gup_huge_pud(pud, pudp, addr, next, flags,
pages, nr))
return 0;
- } else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) {
- if (!gup_huge_pd(__hugepd(pud_val(pud)), addr,
- PUD_SHIFT, next, flags, pages, nr))
- return 0;
} else if (!gup_pmd_range(pudp, pud, addr, next, flags, pages, nr))
return 0;
} while (pudp++, addr = next, addr != end);
@@ -3083,11 +2988,7 @@ static int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, unsigned lo
if (p4d_none(p4d))
return 0;
BUILD_BUG_ON(p4d_huge(p4d));
- if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) {
- if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr,
- P4D_SHIFT, next, flags, pages, nr))
- return 0;
- } else if (!gup_pud_range(p4dp, p4d, addr, next, flags, pages, nr))
+ if (!gup_pud_range(p4dp, p4d, addr, next, flags, pages, nr))
return 0;
} while (p4dp++, addr = next, addr != end);

@@ -3111,10 +3012,6 @@ static void gup_pgd_range(unsigned long addr, unsigned long end,
if (!gup_huge_pgd(pgd, pgdp, addr, next, flags,
pages, nr))
return;
- } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) {
- if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr,
- PGDIR_SHIFT, next, flags, pages, nr))
- return;
} else if (!gup_p4d_range(pgdp, pgd, addr, next, flags, pages, nr))
return;
} while (pgdp++, addr = next, addr != end);
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index f46c80b18ce4..ae2f08ce991b 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -73,45 +73,6 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
return err;
}

-#ifdef CONFIG_ARCH_HAS_HUGEPD
-static int walk_hugepd_range(hugepd_t *phpd, unsigned long addr,
- unsigned long end, struct mm_walk *walk, int pdshift)
-{
- int err = 0;
- const struct mm_walk_ops *ops = walk->ops;
- int shift = hugepd_shift(*phpd);
- int page_size = 1 << shift;
-
- if (!ops->pte_entry)
- return 0;
-
- if (addr & (page_size - 1))
- return 0;
-
- for (;;) {
- pte_t *pte;
-
- spin_lock(&walk->mm->page_table_lock);
- pte = hugepte_offset(*phpd, addr, pdshift);
- err = ops->pte_entry(pte, addr, addr + page_size, walk);
- spin_unlock(&walk->mm->page_table_lock);
-
- if (err)
- break;
- if (addr >= end - page_size)
- break;
- addr += page_size;
- }
- return err;
-}
-#else
-static int walk_hugepd_range(hugepd_t *phpd, unsigned long addr,
- unsigned long end, struct mm_walk *walk, int pdshift)
-{
- return 0;
-}
-#endif
-
static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
@@ -159,10 +120,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
if (walk->vma)
split_huge_pmd(walk->vma, pmd, addr);

- if (is_hugepd(__hugepd(pmd_val(*pmd))))
- err = walk_hugepd_range((hugepd_t *)pmd, addr, next, walk, PMD_SHIFT);
- else
- err = walk_pte_range(pmd, addr, next, walk);
+ err = walk_pte_range(pmd, addr, next, walk);
if (err)
break;

@@ -215,10 +173,7 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
if (pud_none(*pud))
goto again;

- if (is_hugepd(__hugepd(pud_val(*pud))))
- err = walk_hugepd_range((hugepd_t *)pud, addr, next, walk, PUD_SHIFT);
- else
- err = walk_pmd_range(pud, addr, next, walk);
+ err = walk_pmd_range(pud, addr, next, walk);
if (err)
break;
} while (pud++, addr = next, addr != end);
@@ -250,9 +205,7 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
if (err)
break;
}
- if (is_hugepd(__hugepd(p4d_val(*p4d))))
- err = walk_hugepd_range((hugepd_t *)p4d, addr, next, walk, P4D_SHIFT);
- else if (ops->pud_entry || ops->pmd_entry || ops->pte_entry)
+ if (ops->pud_entry || ops->pmd_entry || ops->pte_entry)
err = walk_pud_range(p4d, addr, next, walk);
if (err)
break;
@@ -287,9 +240,7 @@ static int walk_pgd_range(unsigned long addr, unsigned long end,
if (err)
break;
}
- if (is_hugepd(__hugepd(pgd_val(*pgd))))
- err = walk_hugepd_range((hugepd_t *)pgd, addr, next, walk, PGDIR_SHIFT);
- else if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry || ops->pte_entry)
+ if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry || ops->pte_entry)
err = walk_p4d_range(pgd, addr, next, walk);
if (err)
break;
--
2.44.0