ARM: smp: avoid incrementing mm_users on CPU startup

We should not be incrementing mm_users when we startup a secondary
CPU - doing so results in mm_users incrementing by one each time we
hotplug a CPU, which will eventually wrap, and will cause problems.

Other architectures such as x86 do not increment mm_users, but only
mm_count, so we follow that pattern.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 8c1959590252e7161f1da38497eddba9b0538afb..9066473c0ebc3991a2f793e8c78616e26b31decb 100644 (file)
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -310,7 +310,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
         * All kernel threads share the same mm context; grab a
         * reference and switch to it.
         */
-       atomic_inc(&mm->mm_users);
        atomic_inc(&mm->mm_count);
        current->active_mm = mm;
        cpumask_set_cpu(cpu, mm_cpumask(mm));