Commit 42748752 authored Jun 28, 2013 by James Hogan

metag: use clear_tasks_mm_cpumask()



Checking for process->mm is not enough because process' main thread may
exit or detach its mm via use_mm(), but other threads may still have a
valid mm.

To fix this we would need to use find_lock_task_mm(), which would walk
up all threads and returns an appropriate task (with task lock held).

clear_tasks_mm_cpumask() was introduced in v3.5-rc1 to fix this issue,
so let's use it for metag too.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>

parent 5a88130a

arch/metag/kernel/smp.c

+1 −7

Original line number	Diff line number	Diff line
		@@ -276,7 +276,6 @@ static DECLARE_COMPLETION(cpu_killed);
		int __cpuexit __cpu_disable(void)
		{
		unsigned int cpu = smp_processor_id();
		struct task_struct *p;

		/*
		* Take this CPU offline. Once we clear this, we can't return,
		@@ -296,12 +295,7 @@ int __cpuexit __cpu_disable(void)
		flush_cache_all();
		local_flush_tlb_all();

		read_lock(&tasklist_lock);
		for_each_process(p) {
		if (p->mm)
		cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
		}
		read_unlock(&tasklist_lock);
		clear_tasks_mm_cpumask(cpu);

		return 0;
		}

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