diff options
| 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 /include/linux/stop_machine.h | |
| parent | cpu/hotplug: Add __cpuhp_state_add_instance_cpuslocked() (diff) | |
| download | linux-dev-fe5595c074005bd94f0c7d1644175941149f6768.tar.xz linux-dev-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 'include/linux/stop_machine.h')
| -rw-r--r-- | include/linux/stop_machine.h | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h index 3cc9632dcc2a..3d60275e3ba9 100644 --- a/include/linux/stop_machine.h +++ b/include/linux/stop_machine.h @@ -116,15 +116,29 @@ static inline int try_stop_cpus(const struct cpumask *cpumask, * @fn() runs. * * This can be thought of as a very heavy write lock, equivalent to - * grabbing every spinlock in the kernel. */ + * grabbing every spinlock in the kernel. + * + * Protects against CPU hotplug. + */ int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); +/** + * stop_machine_cpuslocked: freeze the machine on all CPUs and run this function + * @fn: the function to run + * @data: the data ptr for the @fn() + * @cpus: the cpus to run the @fn() on (NULL = any online cpu) + * + * Same as above. Must be called from with in a cpus_read_lock() protected + * region. Avoids nested calls to cpus_read_lock(). + */ +int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); + int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); #else /* CONFIG_SMP || CONFIG_HOTPLUG_CPU */ -static inline int stop_machine(cpu_stop_fn_t fn, void *data, - const struct cpumask *cpus) +static inline int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data, + const struct cpumask *cpus) { unsigned long flags; int ret; @@ -134,6 +148,12 @@ static inline int stop_machine(cpu_stop_fn_t fn, void *data, return ret; } +static inline int stop_machine(cpu_stop_fn_t fn, void *data, + const struct cpumask *cpus) +{ + return stop_machine_cpuslocked(fn, data, cpus); +} + static inline int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus) { |