sparc64: Implement __get_user_pages_fast().

It is not sufficient to only implement get_user_pages_fast(), you
must also implement the atomic version __get_user_pages_fast()
otherwise you end up using the weak symbol fallback implementation
which simply returns zero.

This is dangerous, because it causes the futex code to loop forever
if transparent hugepages are supported (see get_futex_key()).

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index 1aed0432c64bab8344ad524ed28b835381588035..ae6ce383d4df6e3188cc547d365f366364f873e9 100644 (file)
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -160,6 +160,36 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
        return 1;
 }
 
+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;
+       int nr = 0;
+
+       start &= PAGE_MASK;
+       addr = start;
+       len = (unsigned long) nr_pages << PAGE_SHIFT;
+       end = start + len;
+
+       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;
+}
+
 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
                        struct page **pages)
 {