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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2017-05-24 10:15:16 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-05-26 10:10:36 +0200 |
| commit | fe5595c074005bd94f0c7d1644175941149f6768 (patch) | |
| tree | dbdc36f344ab77ec7d2624687ae46fc787059b46 /kernel | |
| parent | 9805c6733349ea3ccd22cf75b8ebaabb5290e310 (diff) | |
| download | linux-stable-fe5595c074005bd94f0c7d1644175941149f6768.tar.gz linux-stable-fe5595c074005bd94f0c7d1644175941149f6768.tar.bz2 linux-stable-fe5595c074005bd94f0c7d1644175941149f6768.zip | |
stop_machine: Provide stop_machine_cpuslocked()
Some call sites of stop_machine() are within a get_online_cpus() protected
region.
stop_machine() calls get_online_cpus() as well, which is possible in the
current implementation but prevents converting the hotplug locking to a
percpu rwsem.
Provide stop_machine_cpuslocked() to avoid nested calls to get_online_cpus().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081547.400700852@linutronix.de
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/stop_machine.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 1eb82661ecdb..b7591261652d 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -552,7 +552,8 @@ static int __init cpu_stop_init(void) } early_initcall(cpu_stop_init); -static int __stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus) +int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data, + const struct cpumask *cpus) { struct multi_stop_data msdata = { .fn = fn, @@ -561,6 +562,8 @@ static int __stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cp .active_cpus = cpus, }; + lockdep_assert_cpus_held(); + if (!stop_machine_initialized) { /* * Handle the case where stop_machine() is called @@ -590,9 +593,9 @@ int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus) int ret; /* No CPUs can come up or down during this. */ - get_online_cpus(); - ret = __stop_machine(fn, data, cpus); - put_online_cpus(); + cpus_read_lock(); + ret = stop_machine_cpuslocked(fn, data, cpus); + cpus_read_unlock(); return ret; } EXPORT_SYMBOL_GPL(stop_machine); |