On Mon, May 20, 2019 at 7:30 AM Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
From: Martin Schwidefsky schwidefsky@de.ibm.com
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@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
While this code seems to work fine upstream, when backported to 5.0 it fails to build:
BUILDSTDERR: In file included from ./include/linux/mm.h:98, BUILDSTDERR: from mm/gup.c:6: BUILDSTDERR: mm/gup.c: In function '__get_user_pages_fast': BUILDSTDERR: ./arch/s390/include/asm/pgtable.h:1277:28: error: too many arguments to function 'gup_fast_permitted' BUILDSTDERR: #define gup_fast_permitted gup_fast_permitted BUILDSTDERR: ^~~~~~~~~~~~~~~~~~ BUILDSTDERR: mm/gup.c:1856:6: note: in expansion of macro 'gup_fast_permitted' BUILDSTDERR: if (gup_fast_permitted(start, nr_pages, write)) {
It is missing upstream commit ad8cfb9c42ef83ecf4079bc7d77e6557648e952b mm/gup: Remove the 'write' parameter from gup_fast_permitted()
Justin
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@de.ibm.com
- */
-#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;-}