From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
commit 1a42010cdc26bb7e5912984f3c91b8c6d55f089a upstream.
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@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/Kconfig | 1
arch/s390/include/asm/pgtable.h | 12 +
arch/s390/mm/Makefile | 2
arch/s390/mm/gup.c | 291 ----------------------------------------
4 files changed, 14 insertions(+), 292 deletions(-)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -148,6 +148,7 @@ config S390
select HAVE_FUNCTION_TRACER
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_GCC_PLUGINS
+ select HAVE_GENERIC_GUP
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZ4
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1264,6 +1264,18 @@ static inline pte_t *pte_offset(pmd_t *p
#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
#define pte_unmap(pte) do { } while (0)
+static inline bool gup_fast_permitted(unsigned long start, int nr_pages)
+{
+ unsigned long len, end;
+
+ len = (unsigned long) nr_pages << PAGE_SHIFT;
+ end = start + len;
+ if (end < start)
+ return false;
+ return end <= current->mm->context.asce_limit;
+}
+#define gup_fast_permitted gup_fast_permitted
+
#define pfn_pte(pfn,pgprot) mk_pte_phys(__pa((pfn) << PAGE_SHIFT),(pgprot))
#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)
#define pte_page(x) pfn_to_page(pte_pfn(x))
--- a/arch/s390/mm/Makefile
+++ b/arch/s390/mm/Makefile
@@ -4,7 +4,7 @@
#
obj-y := init.o fault.o extmem.o mmap.o vmem.o maccess.o
-obj-y += page-states.o gup.o pageattr.o pgtable.o pgalloc.o
+obj-y += page-states.o pageattr.o pgtable.o pgalloc.o
obj-$(CONFIG_CMM) += cmm.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
--- a/arch/s390/mm/gup.c
+++ /dev/null
@@ -1,291 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Lockless get_user_pages_fast for s390
- *
- * Copyright IBM Corp. 2010
- * Author(s): Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
- */
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/hugetlb.h>
-#include <linux/vmstat.h>
-#include <linux/pagemap.h>
-#include <linux/rwsem.h>
-#include <asm/pgtable.h>
-
-/*
- * The performance critical leaf functions are made noinline otherwise gcc
- * inlines everything into a single function which results in too much
- * register pressure.
- */
-static inline int gup_pte_range(pmd_t pmd, unsigned long addr,
- unsigned long end, int write, struct page **pages, int *nr)
-{
- struct page *head, *page;
- unsigned long mask;
- pte_t *ptep, pte;
-
- mask = (write ? _PAGE_PROTECT : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
-
- ptep = pte_offset_map(&pmd, addr);
- do {
- pte = *ptep;
- barrier();
- /* Similar to the PMD case, NUMA hinting must take slow path */
- if (pte_protnone(pte))
- return 0;
- if ((pte_val(pte) & mask) != 0)
- return 0;
- VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
- page = pte_page(pte);
- head = compound_head(page);
- if (!page_cache_get_speculative(head))
- return 0;
- if (unlikely(pte_val(pte) != pte_val(*ptep))) {
- put_page(head);
- return 0;
- }
- VM_BUG_ON_PAGE(compound_head(page) != head, page);
- pages[*nr] = page;
- (*nr)++;
-
- } while (ptep++, addr += PAGE_SIZE, addr != end);
-
- return 1;
-}
-
-static inline int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
- unsigned long end, int write, struct page **pages, int *nr)
-{
- struct page *head, *page;
- unsigned long mask;
- int refs;
-
- mask = (write ? _SEGMENT_ENTRY_PROTECT : 0) | _SEGMENT_ENTRY_INVALID;
- if ((pmd_val(pmd) & mask) != 0)
- return 0;
- VM_BUG_ON(!pfn_valid(pmd_val(pmd) >> PAGE_SHIFT));
-
- refs = 0;
- head = pmd_page(pmd);
- 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);
-
- if (!page_cache_add_speculative(head, refs)) {
- *nr -= refs;
- return 0;
- }
-
- if (unlikely(pmd_val(pmd) != pmd_val(*pmdp))) {
- *nr -= refs;
- while (refs--)
- put_page(head);
- return 0;
- }
-
- return 1;
-}
-
-
-static inline 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, pmd;
-
- pmdp = pmd_offset(&pud, addr);
- do {
- pmd = *pmdp;
- barrier();
- next = pmd_addr_end(addr, end);
- if (pmd_none(pmd))
- return 0;
- if (unlikely(pmd_large(pmd))) {
- /*
- * NUMA hinting faults need to be handled in the GUP
- * slowpath for accounting purposes and so that they
- * can be serialised against THP migration.
- */
- if (pmd_protnone(pmd))
- return 0;
- if (!gup_huge_pmd(pmdp, 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 *pudp, pud_t pud, unsigned long addr,
- unsigned long end, int write, struct page **pages, int *nr)
-{
- struct page *head, *page;
- unsigned long mask;
- int refs;
-
- mask = (write ? _REGION_ENTRY_PROTECT : 0) | _REGION_ENTRY_INVALID;
- if ((pud_val(pud) & mask) != 0)
- return 0;
- VM_BUG_ON(!pfn_valid(pud_pfn(pud)));
-
- refs = 0;
- head = pud_page(pud);
- page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
- do {
- VM_BUG_ON_PAGE(compound_head(page) != head, page);
- pages[*nr] = page;
- (*nr)++;
- page++;
- refs++;
- } while (addr += PAGE_SIZE, addr != end);
-
- if (!page_cache_add_speculative(head, refs)) {
- *nr -= refs;
- return 0;
- }
-
- if (unlikely(pud_val(pud) != pud_val(*pudp))) {
- *nr -= refs;
- while (refs--)
- put_page(head);
- return 0;
- }
-
- return 1;
-}
-
-static inline int gup_pud_range(p4d_t p4d, unsigned long addr,
- unsigned long end, int write, struct page **pages, int *nr)
-{
- unsigned long next;
- pud_t *pudp, pud;
-
- pudp = pud_offset(&p4d, addr);
- do {
- pud = *pudp;
- barrier();
- next = pud_addr_end(addr, end);
- if (pud_none(pud))
- return 0;
- if (unlikely(pud_large(pud))) {
- if (!gup_huge_pud(pudp, 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;
-}
-
-static inline int gup_p4d_range(pgd_t pgd, unsigned long addr,
- unsigned long end, int write, struct page **pages, int *nr)
-{
- unsigned long next;
- p4d_t *p4dp, p4d;
-
- p4dp = p4d_offset(&pgd, addr);
- do {
- p4d = *p4dp;
- barrier();
- next = p4d_addr_end(addr, end);
- if (p4d_none(p4d))
- return 0;
- if (!gup_pud_range(p4d, addr, next, write, pages, nr))
- return 0;
- } while (p4dp++, 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, flags;
- pgd_t *pgdp, pgd;
- int nr = 0;
-
- start &= PAGE_MASK;
- addr = start;
- len = (unsigned long) nr_pages << PAGE_SHIFT;
- end = start + len;
- if ((end <= start) || (end > mm->context.asce_limit))
- return 0;
- /*
- * local_irq_save() doesn't prevent pagetable teardown, but does
- * prevent the pagetables from being freed on s390.
- *
- * So long as we atomically load page table pointers versus teardown,
- * we can follow the address down to the the page and take a ref on it.
- */
- local_irq_save(flags);
- pgdp = pgd_offset(mm, addr);
- do {
- pgd = *pgdp;
- barrier();
- next = pgd_addr_end(addr, end);
- if (pgd_none(pgd))
- break;
- if (!gup_p4d_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
- * @write: whether pages will be written to
- * @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, int write,
- struct page **pages)
-{
- int nr, ret;
-
- might_sleep();
- start &= PAGE_MASK;
- nr = __get_user_pages_fast(start, nr_pages, write, pages);
- if (nr == nr_pages)
- return nr;
-
- /* Try to get the remaining pages with get_user_pages */
- start += nr << PAGE_SHIFT;
- pages += nr;
- ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
- write ? FOLL_WRITE : 0);
- /* Have to be a bit careful with return values */
- if (nr > 0)
- ret = (ret < 0) ? nr : ret + nr;
- return ret;
-}
