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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 09:40:21 -0700
commit2a545829b9991872f19176f4e6eb1261695524fc (patch)
treeb72fccad7bd19737fbe82103aeda1014e11f3129
parente81ef812f68862ab4818d34bfab4fdb2edcb242e (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)
{