[S390] don't call handle_mm_fault() if in an atomic context.

There are several places in the futex code where a spin_lock is held
and still uaccesses happen. Deadlocks are avoided by increasing the
preempt count. The pagefault handler will then not take any locks
but will immediately search the fixup tables.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 0 insertions, 3 deletions

diff --git a/arch/s390/lib/uaccess_std.c b/arch/s390/lib/uaccess_std.c
index bbaca66fa293..56a0214e9928 100644
--- a/arch/s390/lib/uaccess_std.c
+++ b/arch/s390/lib/uaccess_std.c
@@ -258,8 +258,6 @@ int futex_atomic_op(int op, int __user *uaddr, int oparg, int *old)
 {
         int oldval = 0, newval, ret;
 
-        pagefault_disable();
-
         switch (op) {
         case FUTEX_OP_SET:
                 __futex_atomic_op("lr %2,%5\n",
@@ -284,7 +282,6 @@ int futex_atomic_op(int op, int __user *uaddr, int oparg, int *old)
         default:
                 ret = -ENOSYS;
         }
-        pagefault_enable();
         *old = oldval;
         return ret;
 }