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

Christophe Leroy
2021-04-28T10:20:57Z

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 <tglx@linutronix.de>
> 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 <dingtianhong@huawei.com>
> 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(-)
>

> diff --git a/mm/ioremap.c b/mm/ioremap.c
> index 3f4d36f9745a..3264d0203785 100644
> --- a/mm/ioremap.c
> +++ b/mm/ioremap.c
> @@ -16,49 +16,16 @@
> #include "pgalloc-track.h"
>
> #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> -static int __read_mostly ioremap_p4d_capable;
> -static int __read_mostly ioremap_pud_capable;
> -static int __read_mostly ioremap_pmd_capable;
> -static int __read_mostly ioremap_huge_disabled;
> +static bool __ro_after_init iomap_max_page_shift = PAGE_SHIFT;

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