[PATCH v7 05/12] mm: HUGE_VMAP arch support cleanup

[PATCH v7 05/12] mm: HUGE_VMAP arch support cleanup

[Nicholas Piggin]

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>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---

Ack or objection from arch maintainers if this goes via the -mm tree?

 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                    | 10 +--
 include/linux/io.h                       |  9 ---
 include/linux/vmalloc.h                  |  6 ++
 init/main.c                              |  1 -
 mm/ioremap.c                             | 88 +++++++++---------------
 10 files changed, 77 insertions(+), 78 deletions(-)

diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index 2ca708ab9b20..597b40405319 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -1,4 +1,12 @@
 #ifndef _ASM_ARM64_VMALLOC_H
 #define _ASM_ARM64_VMALLOC_H
 
+#include <asm/page.h>
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+bool arch_vmap_p4d_supported(pgprot_t prot);
+bool arch_vmap_pud_supported(pgprot_t prot);
+bool arch_vmap_pmd_supported(pgprot_t prot);
+#endif
+
 #endif /* _ASM_ARM64_VMALLOC_H */
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 75df62fea1b6..9df7e0058c78 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1304,12 +1304,12 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 	return dt_virt;
 }
 
-int __init arch_ioremap_p4d_supported(void)
+bool arch_vmap_p4d_supported(pgprot_t prot)
 {
-	return 0;
+	return false;
 }
 
-int __init arch_ioremap_pud_supported(void)
+bool arch_vmap_pud_supported(pgprot_t prot);
 {
 	/*
 	 * Only 4k granule supports level 1 block mappings.
@@ -1319,9 +1319,9 @@ int __init arch_ioremap_pud_supported(void)
 	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
 }
 
-int __init arch_ioremap_pmd_supported(void)
+bool arch_vmap_pmd_supported(pgprot_t prot)
 {
-	/* See arch_ioremap_pud_supported() */
+	/* See arch_vmap_pud_supported() */
 	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
 }
 
diff --git a/arch/powerpc/include/asm/vmalloc.h b/arch/powerpc/include/asm/vmalloc.h
index b992dfaaa161..105abb73f075 100644
--- a/arch/powerpc/include/asm/vmalloc.h
+++ b/arch/powerpc/include/asm/vmalloc.h
@@ -1,4 +1,12 @@
 #ifndef _ASM_POWERPC_VMALLOC_H
 #define _ASM_POWERPC_VMALLOC_H
 
+#include <asm/page.h>
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+bool arch_vmap_p4d_supported(pgprot_t prot);
+bool arch_vmap_pud_supported(pgprot_t prot);
+bool arch_vmap_pmd_supported(pgprot_t prot);
+#endif
+
 #endif /* _ASM_POWERPC_VMALLOC_H */
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 28c784976bed..eca83a50bf2e 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1134,13 +1134,13 @@ void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
 	set_pte_at(mm, addr, ptep, pte);
 }
 
-int __init arch_ioremap_pud_supported(void)
+bool arch_vmap_pud_supported(pgprot_t prot)
 {
 	/* HPT does not cope with large pages in the vmalloc area */
 	return radix_enabled();
 }
 
-int __init arch_ioremap_pmd_supported(void)
+bool arch_vmap_pmd_supported(pgprot_t prot)
 {
 	return radix_enabled();
 }
@@ -1234,7 +1234,7 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 	return 1;
 }
 
-int __init arch_ioremap_p4d_supported(void)
+bool arch_vmap_p4d_supported(pgprot_t prot)
 {
-	return 0;
+	return false;
 }
diff --git a/arch/x86/include/asm/vmalloc.h b/arch/x86/include/asm/vmalloc.h
index 29837740b520..094ea2b565f3 100644
--- a/arch/x86/include/asm/vmalloc.h
+++ b/arch/x86/include/asm/vmalloc.h
@@ -1,6 +1,13 @@
 #ifndef _ASM_X86_VMALLOC_H
 #define _ASM_X86_VMALLOC_H
 
+#include <asm/page.h>
 #include <asm/pgtable_areas.h>
 
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+bool arch_vmap_p4d_supported(pgprot_t prot);
+bool arch_vmap_pud_supported(pgprot_t prot);
+bool arch_vmap_pmd_supported(pgprot_t prot);
+#endif
+
 #endif /* _ASM_X86_VMALLOC_H */
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 84d85dbd1dad..159bfca757b9 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -481,21 +481,21 @@ void iounmap(volatile void __iomem *addr)
 }
 EXPORT_SYMBOL(iounmap);
 
-int __init arch_ioremap_p4d_supported(void)
+bool arch_vmap_p4d_supported(pgprot_t prot)
 {
-	return 0;
+	return false;
 }
 
-int __init arch_ioremap_pud_supported(void)
+bool arch_vmap_pud_supported(pgprot_t prot)
 {
 #ifdef CONFIG_X86_64
 	return boot_cpu_has(X86_FEATURE_GBPAGES);
 #else
-	return 0;
+	return false;
 #endif
 }
 
-int __init arch_ioremap_pmd_supported(void)
+bool arch_vmap_pmd_supported(pgprot_t prot)
 {
 	return boot_cpu_has(X86_FEATURE_PSE);
 }
diff --git a/include/linux/io.h b/include/linux/io.h
index 8394c56babc2..f1effd4d7a3c 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -31,15 +31,6 @@ static inline int ioremap_page_range(unsigned long addr, unsigned long end,
 }
 #endif
 
-#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-void __init ioremap_huge_init(void);
-int arch_ioremap_p4d_supported(void);
-int arch_ioremap_pud_supported(void);
-int arch_ioremap_pmd_supported(void);
-#else
-static inline void ioremap_huge_init(void) { }
-#endif
-
 /*
  * Managed iomap interface
  */
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 0221f852a7e1..3f6bba4cc9bc 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -84,6 +84,12 @@ struct vmap_area {
 	};
 };
 
+#ifndef CONFIG_HAVE_ARCH_HUGE_VMAP
+static inline bool arch_vmap_p4d_supported(pgprot_t prot) { return false; }
+static inline bool arch_vmap_pud_supported(pgprot_t prot) { return false; }
+static inline bool arch_vmap_pmd_supported(pgprot_t prot) { return false; }
+#endif
+
 /*
  *	Highlevel APIs for driver use
  */
diff --git a/init/main.c b/init/main.c
index ae78fb68d231..1c89aa127b8f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -820,7 +820,6 @@ static void __init mm_init(void)
 	pgtable_init();
 	debug_objects_mem_init();
 	vmalloc_init();
-	ioremap_huge_init();
 	/* Should be run before the first non-init thread is created */
 	init_espfix_bsp();
 	/* Should be run after espfix64 is set up. */
diff --git a/mm/ioremap.c b/mm/ioremap.c
index 3f4d36f9745a..c67f91164401 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;
 
 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,
@@ -82,9 +49,13 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 }
 
 static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
-	if (!ioremap_pmd_enabled())
+	if (max_page_shift < PMD_SHIFT)
+		return 0;
+
+	if (!arch_vmap_pmd_supported(prot))
 		return 0;
 
 	if ((end - addr) != PMD_SIZE)
@@ -104,7 +75,7 @@ static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
 
 static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 			phys_addr_t phys_addr, pgprot_t prot,
-			pgtbl_mod_mask *mask)
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
 {
 	pmd_t *pmd;
 	unsigned long next;
@@ -115,7 +86,7 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 	do {
 		next = pmd_addr_end(addr, end);
 
-		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot, max_page_shift)) {
 			*mask |= PGTBL_PMD_MODIFIED;
 			continue;
 		}
@@ -127,9 +98,13 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 }
 
 static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
-	if (!ioremap_pud_enabled())
+	if (max_page_shift < PUD_SHIFT)
+		return 0;
+
+	if (!arch_vmap_pud_supported(prot))
 		return 0;
 
 	if ((end - addr) != PUD_SIZE)
@@ -149,7 +124,7 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
 
 static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
 			phys_addr_t phys_addr, pgprot_t prot,
-			pgtbl_mod_mask *mask)
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
 {
 	pud_t *pud;
 	unsigned long next;
@@ -160,21 +135,25 @@ static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
 	do {
 		next = pud_addr_end(addr, end);
 
-		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot, max_page_shift)) {
 			*mask |= PGTBL_PUD_MODIFIED;
 			continue;
 		}
 
-		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, mask))
+		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, max_page_shift, mask))
 			return -ENOMEM;
 	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
 static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
-	if (!ioremap_p4d_enabled())
+	if (max_page_shift < P4D_SHIFT)
+		return 0;
+
+	if (!arch_vmap_p4d_supported(prot))
 		return 0;
 
 	if ((end - addr) != P4D_SIZE)
@@ -194,7 +173,7 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
 
 static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 			phys_addr_t phys_addr, pgprot_t prot,
-			pgtbl_mod_mask *mask)
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
 {
 	p4d_t *p4d;
 	unsigned long next;
@@ -205,19 +184,20 @@ static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 	do {
 		next = p4d_addr_end(addr, end);
 
-		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot, max_page_shift)) {
 			*mask |= PGTBL_P4D_MODIFIED;
 			continue;
 		}
 
-		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, mask))
+		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, max_page_shift, mask))
 			return -ENOMEM;
 	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
 static int vmap_range(unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
 	pgd_t *pgd;
 	unsigned long start;
@@ -232,7 +212,7 @@ static int vmap_range(unsigned long addr, unsigned long end,
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);
-		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, &mask);
+		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, max_page_shift, &mask);
 		if (err)
 			break;
 	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
@@ -248,7 +228,7 @@ static int vmap_range(unsigned long addr, unsigned long end,
 int ioremap_page_range(unsigned long addr,
 		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {
-	return vmap_range(addr, end, phys_addr, prot);
+	return vmap_range(addr, end, phys_addr, prot, iomap_max_page_shift);
 }
 
 #ifdef CONFIG_GENERIC_IOREMAP
-- 
2.23.0


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Re: [PATCH v7 05/12] mm: HUGE_VMAP arch support cleanup

[Tang Yizhou]

On 2020/8/25 22:57, Nicholas Piggin wrote:
> -int __init arch_ioremap_pud_supported(void)
> +bool arch_vmap_pud_supported(pgprot_t prot);
>  {
>  	/*
>  	 * Only 4k granule supports level 1 block mappings.
> @@ -1319,9 +1319,9 @@ int __init arch_ioremap_pud_supported(void)
>  	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
>  }

There is a compilation error because of the redundant semicolon at arch_vmap_pud_supported().


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Re: [PATCH v7 05/12] mm: HUGE_VMAP arch support cleanup

[Nicholas Piggin]

Excerpts from Tang Yizhou's message of September 11, 2020 8:36 pm:
> On 2020/8/25 22:57, Nicholas Piggin wrote:
>> -int __init arch_ioremap_pud_supported(void)
>> +bool arch_vmap_pud_supported(pgprot_t prot);
>>  {
>>  	/*
>>  	 * Only 4k granule supports level 1 block mappings.
>> @@ -1319,9 +1319,9 @@ int __init arch_ioremap_pud_supported(void)
>>  	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
>>  }
> 
> There is a compilation error because of the redundant semicolon at arch_vmap_pud_supported().

Huh thanks, I didn't see that for some reason.

I'll fix it up and re-send.

Thanks,
Nick


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[PATCH v7 07/12] arm64: inline huge vmap supported functions

[Nicholas Piggin]

This allows unsupported levels to be constant folded away, and so
p4d_free_pud_page can be removed because it's no longer linked to.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---

Ack or objection if this goes via the -mm tree?

 arch/arm64/include/asm/vmalloc.h | 23 ++++++++++++++++++++---
 arch/arm64/mm/mmu.c              | 26 --------------------------
 2 files changed, 20 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index 597b40405319..fc9a12d6cc1a 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -4,9 +4,26 @@
 #include <asm/page.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-bool arch_vmap_p4d_supported(pgprot_t prot);
-bool arch_vmap_pud_supported(pgprot_t prot);
-bool arch_vmap_pmd_supported(pgprot_t prot);
+static inline bool arch_vmap_p4d_supported(pgprot_t prot)
+{
+	return false;
+}
+
+static inline bool arch_vmap_pud_supported(pgprot_t prot)
+{
+	/*
+	 * Only 4k granule supports level 1 block mappings.
+	 * SW table walks can't handle removal of intermediate entries.
+	 */
+	return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
+	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
+}
+
+static inline bool arch_vmap_pmd_supported(pgprot_t prot)
+{
+	/* See arch_vmap_pud_supported() */
+	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
+}
 #endif
 
 #endif /* _ASM_ARM64_VMALLOC_H */
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9df7e0058c78..07093e148957 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1304,27 +1304,6 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 	return dt_virt;
 }
 
-bool arch_vmap_p4d_supported(pgprot_t prot)
-{
-	return false;
-}
-
-bool arch_vmap_pud_supported(pgprot_t prot);
-{
-	/*
-	 * Only 4k granule supports level 1 block mappings.
-	 * SW table walks can't handle removal of intermediate entries.
-	 */
-	return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
-	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
-}
-
-bool arch_vmap_pmd_supported(pgprot_t prot)
-{
-	/* See arch_vmap_pud_supported() */
-	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
-}
-
 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
 {
 	pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
@@ -1416,11 +1395,6 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
 	return 1;
 }
 
-int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
-{
-	return 0;	/* Don't attempt a block mapping */
-}
-
 #ifdef CONFIG_MEMORY_HOTPLUG
 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
 {
-- 
2.23.0


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Re: [PATCH v7 07/12] arm64: inline huge vmap supported functions

[Catalin Marinas]

On Wed, Aug 26, 2020 at 12:57:48AM +1000, Nicholas Piggin wrote:
> This allows unsupported levels to be constant folded away, and so
> p4d_free_pud_page can be removed because it's no longer linked to.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> 
> Ack or objection if this goes via the -mm tree?

No objections.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

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