[PATCH] mm: pagefault_{disable,enable}()

Introduce pagefault_{disable,enable}() and use these where previously we did
manual preempt increments/decrements to make the pagefault handler do the
atomic thing.

Currently they still rely on the increased preempt count, but do not rely on
the disabled preemption, this might go away in the future.

(NOTE: the extra barrier() in pagefault_disable might fix some holes on
       machines which have too many registers for their own good)

[heiko.carstens@de.ibm.com: s390 fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h
index df893c160318..f422df0956a2 100644
--- a/include/asm-generic/futex.h
+++ b/include/asm-generic/futex.h
@@ -21,7 +21,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
                 return -EFAULT;
 
-        inc_preempt_count();
+        pagefault_disable();
 
         switch (op) {
         case FUTEX_OP_SET:
@@ -33,7 +33,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
                 ret = -ENOSYS;
         }
 
-        dec_preempt_count();
+        pagefault_enable();
 
         if (!ret) {
                 switch (cmp) {