softirq: Use __this_cpu_write() in takeover_tasklets()

The code is executed with interrupts disabled, so it's safe to use
__this_cpu_write().

[ tglx: Massaged changelog ]
Signed-off-by: Muchun Song <smuchun@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: joel@joelfernandes.org
Cc: rostedt@goodmis.org
Cc: frederic@kernel.org
Cc: paulmck@linux.vnet.ibm.com
Cc: alexander.levin@verizon.com
Cc: peterz@infradead.org
Link: https://lkml.kernel.org/r/20190618143305.2038-1-smuchun@gmail.com

kernel/softirq.c

@@ -650,7 +650,7 @@ static int takeover_tasklets(unsigned int cpu)
 	/* Find end, append list for that CPU. */
 	if (&per_cpu(tasklet_vec, cpu).head != per_cpu(tasklet_vec, cpu).tail) {
 		*__this_cpu_read(tasklet_vec.tail) = per_cpu(tasklet_vec, cpu).head;
-		this_cpu_write(tasklet_vec.tail, per_cpu(tasklet_vec, cpu).tail);
+		__this_cpu_write(tasklet_vec.tail, per_cpu(tasklet_vec, cpu).tail);
 		per_cpu(tasklet_vec, cpu).head = NULL;
 		per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head;
 	}