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s390/mm: convert to the generic get_user_pages_fast code
Define the gup_fast_permitted to check against the asce_limit of the mm attached to the current task, then replace the s390 specific gup code with the generic implementation in mm/gup.c. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
parent
d1874a0c28
commit
1a42010cdc
4 changed files with 14 additions and 292 deletions
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@ -149,6 +149,7 @@ config S390
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select HAVE_FUNCTION_TRACER
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select HAVE_FUTEX_CMPXCHG if FUTEX
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select HAVE_GCC_PLUGINS
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select HAVE_GENERIC_GUP
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select HAVE_KERNEL_BZIP2
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select HAVE_KERNEL_GZIP
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select HAVE_KERNEL_LZ4
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@ -1265,6 +1265,18 @@ static inline pte_t *pte_offset(pmd_t *pmd, unsigned long address)
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#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
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#define pte_unmap(pte) do { } while (0)
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static inline bool gup_fast_permitted(unsigned long start, int nr_pages)
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{
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unsigned long len, end;
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len = (unsigned long) nr_pages << PAGE_SHIFT;
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end = start + len;
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if (end < start)
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return false;
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return end <= current->mm->context.asce_limit;
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}
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#define gup_fast_permitted gup_fast_permitted
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#define pfn_pte(pfn,pgprot) mk_pte_phys(__pa((pfn) << PAGE_SHIFT),(pgprot))
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#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)
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#define pte_page(x) pfn_to_page(pte_pfn(x))
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@ -4,7 +4,7 @@
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#
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obj-y := init.o fault.o extmem.o mmap.o vmem.o maccess.o
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obj-y += page-states.o gup.o pageattr.o pgtable.o pgalloc.o
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obj-y += page-states.o pageattr.o pgtable.o pgalloc.o
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obj-$(CONFIG_CMM) += cmm.o
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obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
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@ -1,291 +0,0 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Lockless get_user_pages_fast for s390
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*
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* Copyright IBM Corp. 2010
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/vmstat.h>
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#include <linux/pagemap.h>
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#include <linux/rwsem.h>
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#include <asm/pgtable.h>
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/*
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* The performance critical leaf functions are made noinline otherwise gcc
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* inlines everything into a single function which results in too much
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* register pressure.
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*/
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static inline int gup_pte_range(pmd_t pmd, unsigned long addr,
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unsigned long end, int write, struct page **pages, int *nr)
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{
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struct page *head, *page;
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unsigned long mask;
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pte_t *ptep, pte;
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mask = (write ? _PAGE_PROTECT : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
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ptep = pte_offset_map(&pmd, addr);
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do {
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pte = *ptep;
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barrier();
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/* Similar to the PMD case, NUMA hinting must take slow path */
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if (pte_protnone(pte))
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return 0;
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if ((pte_val(pte) & mask) != 0)
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return 0;
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VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
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page = pte_page(pte);
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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return 0;
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if (unlikely(pte_val(pte) != pte_val(*ptep))) {
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put_page(head);
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return 0;
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}
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VM_BUG_ON_PAGE(compound_head(page) != head, page);
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pages[*nr] = page;
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(*nr)++;
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} while (ptep++, addr += PAGE_SIZE, addr != end);
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return 1;
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}
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static inline int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
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unsigned long end, int write, struct page **pages, int *nr)
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{
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struct page *head, *page;
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unsigned long mask;
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int refs;
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mask = (write ? _SEGMENT_ENTRY_PROTECT : 0) | _SEGMENT_ENTRY_INVALID;
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if ((pmd_val(pmd) & mask) != 0)
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return 0;
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VM_BUG_ON(!pfn_valid(pmd_val(pmd) >> PAGE_SHIFT));
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refs = 0;
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head = pmd_page(pmd);
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page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
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do {
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VM_BUG_ON(compound_head(page) != head);
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pages[*nr] = page;
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(*nr)++;
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page++;
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refs++;
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} while (addr += PAGE_SIZE, addr != end);
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if (!page_cache_add_speculative(head, refs)) {
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*nr -= refs;
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return 0;
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}
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if (unlikely(pmd_val(pmd) != pmd_val(*pmdp))) {
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*nr -= refs;
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while (refs--)
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put_page(head);
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return 0;
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}
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return 1;
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}
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static inline int gup_pmd_range(pud_t pud, unsigned long addr,
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unsigned long end, int write, struct page **pages, int *nr)
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{
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unsigned long next;
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pmd_t *pmdp, pmd;
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pmdp = pmd_offset(&pud, addr);
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do {
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pmd = *pmdp;
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barrier();
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next = pmd_addr_end(addr, end);
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if (pmd_none(pmd))
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return 0;
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if (unlikely(pmd_large(pmd))) {
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/*
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* NUMA hinting faults need to be handled in the GUP
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* slowpath for accounting purposes and so that they
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* can be serialised against THP migration.
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*/
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if (pmd_protnone(pmd))
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return 0;
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if (!gup_huge_pmd(pmdp, pmd, addr, next,
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write, pages, nr))
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return 0;
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} else if (!gup_pte_range(pmd, addr, next,
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write, pages, nr))
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return 0;
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} while (pmdp++, addr = next, addr != end);
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return 1;
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}
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static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr,
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unsigned long end, int write, struct page **pages, int *nr)
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{
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struct page *head, *page;
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unsigned long mask;
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int refs;
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mask = (write ? _REGION_ENTRY_PROTECT : 0) | _REGION_ENTRY_INVALID;
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if ((pud_val(pud) & mask) != 0)
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return 0;
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VM_BUG_ON(!pfn_valid(pud_pfn(pud)));
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refs = 0;
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head = pud_page(pud);
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page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
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do {
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VM_BUG_ON_PAGE(compound_head(page) != head, page);
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pages[*nr] = page;
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(*nr)++;
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page++;
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refs++;
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} while (addr += PAGE_SIZE, addr != end);
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if (!page_cache_add_speculative(head, refs)) {
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*nr -= refs;
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return 0;
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}
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if (unlikely(pud_val(pud) != pud_val(*pudp))) {
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*nr -= refs;
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while (refs--)
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put_page(head);
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return 0;
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}
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return 1;
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}
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static inline int gup_pud_range(p4d_t p4d, unsigned long addr,
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unsigned long end, int write, struct page **pages, int *nr)
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{
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unsigned long next;
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pud_t *pudp, pud;
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pudp = pud_offset(&p4d, addr);
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do {
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pud = *pudp;
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barrier();
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next = pud_addr_end(addr, end);
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if (pud_none(pud))
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return 0;
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if (unlikely(pud_large(pud))) {
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if (!gup_huge_pud(pudp, pud, addr, next, write, pages,
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nr))
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return 0;
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} else if (!gup_pmd_range(pud, addr, next, write, pages,
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nr))
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return 0;
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} while (pudp++, addr = next, addr != end);
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return 1;
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}
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static inline int gup_p4d_range(pgd_t pgd, unsigned long addr,
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unsigned long end, int write, struct page **pages, int *nr)
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{
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unsigned long next;
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p4d_t *p4dp, p4d;
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p4dp = p4d_offset(&pgd, addr);
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do {
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p4d = *p4dp;
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barrier();
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next = p4d_addr_end(addr, end);
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if (p4d_none(p4d))
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return 0;
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if (!gup_pud_range(p4d, addr, next, write, pages, nr))
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return 0;
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} while (p4dp++, addr = next, addr != end);
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return 1;
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}
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/*
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* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
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* back to the regular GUP.
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* Note a difference with get_user_pages_fast: this always returns the
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* number of pages pinned, 0 if no pages were pinned.
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*/
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int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
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struct page **pages)
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{
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struct mm_struct *mm = current->mm;
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unsigned long addr, len, end;
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unsigned long next, flags;
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pgd_t *pgdp, pgd;
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int nr = 0;
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start &= PAGE_MASK;
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addr = start;
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len = (unsigned long) nr_pages << PAGE_SHIFT;
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end = start + len;
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if ((end <= start) || (end > mm->context.asce_limit))
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return 0;
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/*
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* local_irq_save() doesn't prevent pagetable teardown, but does
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* prevent the pagetables from being freed on s390.
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*
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* So long as we atomically load page table pointers versus teardown,
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* we can follow the address down to the the page and take a ref on it.
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*/
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local_irq_save(flags);
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pgdp = pgd_offset(mm, addr);
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do {
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pgd = *pgdp;
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barrier();
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next = pgd_addr_end(addr, end);
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if (pgd_none(pgd))
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break;
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if (!gup_p4d_range(pgd, addr, next, write, pages, &nr))
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break;
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} while (pgdp++, addr = next, addr != end);
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local_irq_restore(flags);
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return nr;
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}
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/**
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* get_user_pages_fast() - pin user pages in memory
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* @start: starting user address
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* @nr_pages: number of pages from start to pin
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* @write: whether pages will be written to
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* @pages: array that receives pointers to the pages pinned.
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* Should be at least nr_pages long.
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*
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* Attempt to pin user pages in memory without taking mm->mmap_sem.
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* If not successful, it will fall back to taking the lock and
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* calling get_user_pages().
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*
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* Returns number of pages pinned. This may be fewer than the number
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* requested. If nr_pages is 0 or negative, returns 0. If no pages
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* were pinned, returns -errno.
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*/
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int get_user_pages_fast(unsigned long start, int nr_pages, int write,
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struct page **pages)
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{
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int nr, ret;
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might_sleep();
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start &= PAGE_MASK;
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nr = __get_user_pages_fast(start, nr_pages, write, pages);
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if (nr == nr_pages)
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return nr;
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/* Try to get the remaining pages with get_user_pages */
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start += nr << PAGE_SHIFT;
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pages += nr;
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ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
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write ? FOLL_WRITE : 0);
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/* Have to be a bit careful with return values */
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if (nr > 0)
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ret = (ret < 0) ? nr : ret + nr;
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return ret;
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}
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