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authorDavid S. Miller <davem@davemloft.net>2014-10-24 09:59:02 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-10-30 09:38:28 -0700
commitf5dcee1c537f977545fc9652ace5c2ac93a519ca (patch)
tree8183a06646a046a113c47397365b028e473014ba
parentd9cd30ad9f2d40780894e30bb23d168db1b5dfb8 (diff)
sparc64: Implement __get_user_pages_fast().
[ Upstream commit 06090e8ed89ea2113a236befb41f71d51f100e60 ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/sparc/mm/gup.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index 1aed0432c64b..ae6ce383d4df 100644
--- 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)
{