sched/preempt, futex: Disable preemption in UP futex_atomic_op_inuser() explicitly

[firefly-linux-kernel-4.4.55.git] / include / asm-generic / futex.h

diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h
index b59b5a52637ec78397262862b06796b5d2fa2329..358601750fe72eea3429f9fe9ce8047af9ef7542 100644 (file)
--- a/include/asm-generic/futex.h
+++ b/include/asm-generic/futex.h
@@ -8,8 +8,7 @@
 #ifndef CONFIG_SMP
 /*
  * The following implementation only for uniprocessor machines.
- * For UP, it's relies on the fact that pagefault_disable() also disables
- * preemption to ensure mutual exclusion.
+ * It relies on preempt_disable() ensuring mutual exclusion.
  *
  */
 
@@ -38,6 +37,7 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
        if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
                oparg = 1 << oparg;
 
+       preempt_disable();
        pagefault_disable();
 
        ret = -EFAULT;
@@ -72,6 +72,7 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
 
 out_pagefault_enable:
        pagefault_enable();
+       preempt_enable();
 
        if (ret == 0) {
                switch (cmp) {