MIPS: use the generic get_user_pages_fast code (446f062b) · Commits · 戴 / test

arch/mips/Kconfig

+2 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,7 @@ config MIPS
		select GENERIC_SCHED_CLOCK if !CAVIUM_OCTEON_SOC
		select GENERIC_SMP_IDLE_THREAD
		select GENERIC_TIME_VSYSCALL
		select GUP_GET_PTE_LOW_HIGH if CPU_MIPS32 && PHYS_ADDR_T_64BIT
		select HANDLE_DOMAIN_IRQ
		select HAVE_ARCH_COMPILER_H
		select HAVE_ARCH_JUMP_LABEL
		@@ -55,6 +56,7 @@ config MIPS
		select HAVE_FTRACE_MCOUNT_RECORD
		select HAVE_FUNCTION_GRAPH_TRACER
		select HAVE_FUNCTION_TRACER
		select HAVE_GENERIC_GUP
		select HAVE_IDE
		select HAVE_IOREMAP_PROT
		select HAVE_IRQ_EXIT_ON_IRQ_STACK

arch/mips/include/asm/pgtable.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -20,6 +20,7 @@
		#include <asm/cmpxchg.h>
		#include <asm/io.h>
		#include <asm/pgtable-bits.h>
		#include <asm/cpu-features.h>

		struct mm_struct;
		struct vm_area_struct;
		@@ -626,6 +627,8 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,

		#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

		#define gup_fast_permitted(start, end) (!cpu_has_dc_aliases)

		#include <asm-generic/pgtable.h>

		/*

arch/mips/mm/Makefile

+0 −1

Original line number	Diff line number	Diff line
		@@ -7,7 +7,6 @@ obj-y += cache.o
		obj-y += context.o
		obj-y += extable.o
		obj-y += fault.o
		obj-y += gup.o
		obj-y += init.o
		obj-y += mmap.o
		obj-y += page.o

arch/mips/mm/gup.c

deleted100644 → 0

+0 −303

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		/*
		* Lockless get_user_pages_fast for MIPS
		*
		* Copyright (C) 2008 Nick Piggin
		* Copyright (C) 2008 Novell Inc.
		* Copyright (C) 2011 Ralf Baechle
		*/
		#include <linux/sched.h>
		#include <linux/mm.h>
		#include <linux/vmstat.h>
		#include <linux/highmem.h>
		#include <linux/swap.h>
		#include <linux/hugetlb.h>

		#include <asm/cpu-features.h>
		#include <asm/pgtable.h>

		static inline pte_t gup_get_pte(pte_t *ptep)
		{
		#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
		pte_t pte;

		retry:
		pte.pte_low = ptep->pte_low;
		smp_rmb();
		pte.pte_high = ptep->pte_high;
		smp_rmb();
		if (unlikely(pte.pte_low != ptep->pte_low))
		goto retry;

		return pte;
		#else
		return READ_ONCE(*ptep);
		#endif
		}

		static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
		int write, struct page *pages, int nr)
		{
		pte_t *ptep = pte_offset_map(&pmd, addr);
		do {
		pte_t pte = gup_get_pte(ptep);
		struct page *page;

		if (!pte_present(pte) \|\|
		pte_special(pte) \|\| (write && !pte_write(pte))) {
		pte_unmap(ptep);
		return 0;
		}
		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
		page = pte_page(pte);
		get_page(page);
		SetPageReferenced(page);
		pages[*nr] = page;
		(*nr)++;

		} while (ptep++, addr += PAGE_SIZE, addr != end);

		pte_unmap(ptep - 1);
		return 1;
		}

		static inline void get_head_page_multiple(struct page *page, int nr)
		{
		VM_BUG_ON(page != compound_head(page));
		VM_BUG_ON(page_count(page) == 0);
		page_ref_add(page, nr);
		SetPageReferenced(page);
		}

		static int gup_huge_pmd(pmd_t pmd, unsigned long addr, unsigned long end,
		int write, struct page *pages, int nr)
		{
		pte_t pte = (pte_t )&pmd;
		struct page head, page;
		int refs;

		if (write && !pte_write(pte))
		return 0;
		/* hugepages are never "special" */
		VM_BUG_ON(pte_special(pte));
		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));

		refs = 0;
		head = pte_page(pte);
		page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
		do {
		VM_BUG_ON(compound_head(page) != head);
		pages[*nr] = page;
		(*nr)++;
		page++;
		refs++;
		} while (addr += PAGE_SIZE, addr != end);

		get_head_page_multiple(head, refs);
		return 1;
		}

		static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
		int write, struct page *pages, int nr)
		{
		unsigned long next;
		pmd_t *pmdp;

		pmdp = pmd_offset(&pud, addr);
		do {
		pmd_t pmd = *pmdp;

		next = pmd_addr_end(addr, end);
		if (pmd_none(pmd))
		return 0;
		if (unlikely(pmd_huge(pmd))) {
		if (!gup_huge_pmd(pmd, addr, next, write, pages,nr))
		return 0;
		} else {
		if (!gup_pte_range(pmd, addr, next, write, pages,nr))
		return 0;
		}
		} while (pmdp++, addr = next, addr != end);

		return 1;
		}

		static int gup_huge_pud(pud_t pud, unsigned long addr, unsigned long end,
		int write, struct page *pages, int nr)
		{
		pte_t pte = (pte_t )&pud;
		struct page head, page;
		int refs;

		if (write && !pte_write(pte))
		return 0;
		/* hugepages are never "special" */
		VM_BUG_ON(pte_special(pte));
		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));

		refs = 0;
		head = pte_page(pte);
		page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
		do {
		VM_BUG_ON(compound_head(page) != head);
		pages[*nr] = page;
		(*nr)++;
		page++;
		refs++;
		} while (addr += PAGE_SIZE, addr != end);

		get_head_page_multiple(head, refs);
		return 1;
		}

		static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
		int write, struct page *pages, int nr)
		{
		unsigned long next;
		pud_t *pudp;

		pudp = pud_offset(&pgd, addr);
		do {
		pud_t pud = *pudp;

		next = pud_addr_end(addr, end);
		if (pud_none(pud))
		return 0;
		if (unlikely(pud_huge(pud))) {
		if (!gup_huge_pud(pud, addr, next, write, pages,nr))
		return 0;
		} else {
		if (!gup_pmd_range(pud, addr, next, write, pages,nr))
		return 0;
		}
		} while (pudp++, addr = next, addr != end);

		return 1;
		}

		/*
		* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
		* back to the regular GUP.
		* Note a difference with get_user_pages_fast: this always returns the
		* number of pages pinned, 0 if no pages were pinned.
		*/
		int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
		struct page **pages)
		{
		struct mm_struct *mm = current->mm;
		unsigned long addr, len, end;
		unsigned long next;
		unsigned long flags;
		pgd_t *pgdp;
		int nr = 0;

		start &= PAGE_MASK;
		addr = start;
		len = (unsigned long) nr_pages << PAGE_SHIFT;
		end = start + len;
		if (unlikely(!access_ok((void __user *)start, len)))
		return 0;

		/*
		* XXX: batch / limit 'nr', to avoid large irq off latency
		* needs some instrumenting to determine the common sizes used by
		* important workloads (eg. DB2), and whether limiting the batch
		* size will decrease performance.
		*
		* It seems like we're in the clear for the moment. Direct-IO is
		* the main guy that batches up lots of get_user_pages, and even
		* they are limited to 64-at-a-time which is not so many.
		*/
		/*
		* This doesn't prevent pagetable teardown, but does prevent
		* the pagetables and pages from being freed.
		*
		* So long as we atomically load page table pointers versus teardown,
		* we can follow the address down to the page and take a ref on it.
		*/
		local_irq_save(flags);
		pgdp = pgd_offset(mm, addr);
		do {
		pgd_t pgd = *pgdp;

		next = pgd_addr_end(addr, end);
		if (pgd_none(pgd))
		break;
		if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
		break;
		} while (pgdp++, addr = next, addr != end);
		local_irq_restore(flags);

		return nr;
		}

		/**
		* get_user_pages_fast() - pin user pages in memory
		* @start: starting user address
		* @nr_pages: number of pages from start to pin
		* @gup_flags: flags modifying pin behaviour
		* @pages: array that receives pointers to the pages pinned.
		* Should be at least nr_pages long.
		*
		* Attempt to pin user pages in memory without taking mm->mmap_sem.
		* If not successful, it will fall back to taking the lock and
		* calling get_user_pages().
		*
		* Returns number of pages pinned. This may be fewer than the number
		* requested. If nr_pages is 0 or negative, returns 0. If no pages
		* were pinned, returns -errno.
		*/
		int get_user_pages_fast(unsigned long start, int nr_pages,
		unsigned int gup_flags, struct page **pages)
		{
		struct mm_struct *mm = current->mm;
		unsigned long addr, len, end;
		unsigned long next;
		pgd_t *pgdp;
		int ret, nr = 0;

		start &= PAGE_MASK;
		addr = start;
		len = (unsigned long) nr_pages << PAGE_SHIFT;

		end = start + len;
		if (end < start \|\| cpu_has_dc_aliases)
		goto slow_irqon;

		/* XXX: batch / limit 'nr' */
		local_irq_disable();
		pgdp = pgd_offset(mm, addr);
		do {
		pgd_t pgd = *pgdp;

		next = pgd_addr_end(addr, end);
		if (pgd_none(pgd))
		goto slow;
		if (!gup_pud_range(pgd, addr, next, gup_flags & FOLL_WRITE,
		pages, &nr))
		goto slow;
		} while (pgdp++, addr = next, addr != end);
		local_irq_enable();

		VM_BUG_ON(nr != (end - start) >> PAGE_SHIFT);
		return nr;
		slow:
		local_irq_enable();

		slow_irqon:
		/* Try to get the remaining pages with get_user_pages */
		start += nr << PAGE_SHIFT;
		pages += nr;

		ret = get_user_pages_unlocked(start, (end - start) >> PAGE_SHIFT,
		pages, gup_flags);

		/* Have to be a bit careful with return values */
		if (nr > 0) {
		if (ret < 0)
		ret = nr;
		else
		ret += nr;
		}
		return ret;
		}

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