Re: [PATCH v13 06/14] mm: HUGE_VMAP arch support cleanup

Le 17/03/2021 à 07:23, Nicholas Piggin a écrit :

This changes the awkward approach where architectures provide init
functions to determine which levels they can provide large mappings for,
to one where the arch is queried for each call.

This removes code and indirection, and allows constant-folding of dead
code for unsupported levels.

This also adds a prot argument to the arch query. This is unused
currently but could help with some architectures (e.g., some powerpc
processors can't map uncacheable memory with large pages).

Cc: linuxppc-dev@lists.ozlabs.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Thomas Gleixner <redacted>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Reviewed-by: Ding Tianhong <redacted>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
  arch/arm64/include/asm/vmalloc.h         |  8 ++
  arch/arm64/mm/mmu.c                      | 10 +--
  arch/powerpc/include/asm/vmalloc.h       |  8 ++
  arch/powerpc/mm/book3s64/radix_pgtable.c |  8 +-
  arch/x86/include/asm/vmalloc.h           |  7 ++
  arch/x86/mm/ioremap.c                    | 12 +--
  include/linux/io.h                       |  9 ---
  include/linux/vmalloc.h                  |  6 ++
  init/main.c                              |  1 -
  mm/debug_vm_pgtable.c                    |  4 +-
  mm/ioremap.c                             | 94 ++++++++++--------------
  11 files changed, 87 insertions(+), 80 deletions(-)

Must be an int, not a bool.

  
  static int __init set_nohugeiomap(char *str)
  {
-	ioremap_huge_disabled = 1;
+	iomap_max_page_shift = P4D_SHIFT;
  	return 0;
  }
  early_param("nohugeiomap", set_nohugeiomap);
-
-void __init ioremap_huge_init(void)
-{
-	if (!ioremap_huge_disabled) {
-		if (arch_ioremap_p4d_supported())
-			ioremap_p4d_capable = 1;
-		if (arch_ioremap_pud_supported())
-			ioremap_pud_capable = 1;
-		if (arch_ioremap_pmd_supported())
-			ioremap_pmd_capable = 1;
-	}
-}
-
-static inline int ioremap_p4d_enabled(void)
-{
-	return ioremap_p4d_capable;
-}
-
-static inline int ioremap_pud_enabled(void)
-{
-	return ioremap_pud_capable;
-}
-
-static inline int ioremap_pmd_enabled(void)
-{
-	return ioremap_pmd_capable;
-}
-
-#else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */
-static inline int ioremap_p4d_enabled(void) { return 0; }
-static inline int ioremap_pud_enabled(void) { return 0; }
-static inline int ioremap_pmd_enabled(void) { return 0; }
+#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+static const bool iomap_max_page_shift = PAGE_SHIFT;
  #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
  
  static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,

Christophe

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