Commit-ID:  2337e879e8805a630b418f3e73a98084d4724b83
Gitweb:     http://git.kernel.org/tip/2337e879e8805a630b418f3e73a98084d4724b83
Author:     Sebastian Andrzej Siewior <[email protected]>
AuthorDate: Wed, 24 May 2017 10:15:26 +0200
Committer:  Thomas Gleixner <[email protected]>
CommitDate: Fri, 26 May 2017 10:10:41 +0200

s390/kernel: Use stop_machine_cpuslocked()

stp_work_fn() holds get_online_cpus() while invoking stop_machine().

stop_machine() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.

Use stop_machine_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.

Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: [email protected]
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]

---
 arch/s390/kernel/time.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index c3a52f9..192efdf 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -636,10 +636,10 @@ static void stp_work_fn(struct work_struct *work)
                goto out_unlock;
 
        memset(&stp_sync, 0, sizeof(stp_sync));
-       get_online_cpus();
+       cpus_read_lock();
        atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
-       stop_machine(stp_sync_clock, &stp_sync, cpu_online_mask);
-       put_online_cpus();
+       stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask);
+       cpus_read_unlock();
 
        if (!check_sync_clock())
                /*

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