[PATCH 6/8] RISC-V: Use mmgrab()

[Palmer Dabbelt]

f1f1007644ff ("mm: add new mmgrab() helper") added a helper that we
missed out on.

Signed-off-by: Palmer Dabbelt <pal...@sifive.com>
---
 arch/riscv/kernel/smpboot.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index e1f6a5ad0416..5437a04babcd 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -30,6 +30,7 @@
 #include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/sched/task_stack.h>
+#include <linux/sched/mm.h>
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
@@ -79,8 +80,8 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
         * the spinning harts that they can continue the boot process.
         */
        smp_mb();
-       __cpu_up_stack_pointer[cpu] = task_stack_page(tidle) + THREAD_SIZE;
-       __cpu_up_task_pointer[cpu] = tidle;
+       WRITE_ONCE(__cpu_up_stack_pointer[cpu], task_stack_page(tidle) + 
THREAD_SIZE);
+       WRITE_ONCE(__cpu_up_task_pointer[cpu], tidle);
 
        while (!cpu_online(cpu))
                cpu_relax();
@@ -100,7 +101,7 @@ asmlinkage void __init smp_callin(void)
        struct mm_struct *mm = &init_mm;
 
        /* All kernel threads share the same mm context.  */
-       atomic_inc(&mm->mm_count);
+       mmgrab(mm);
        current->active_mm = mm;
 
        trap_init();
-- 
2.16.4