[PATCH 13/21] padata: Convert to hotplug state machine

Sebastian Andrzej Siewior
2016-09-06T17:07:14Z

Install the callbacks via the state machine. CPU-hotplug multinstance support
is used with the nocalls() version. Maybe parts of padata_alloc() could be
moved into the online callback so that we could invoke ->startup callback for
instance and drop get_online_cpus().

Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
include/linux/padata.h | 2 +-
kernel/padata.c | 92 ++++++++++++++++++++++++++++----------------------
2 files changed, 53 insertions(+), 41 deletions(-)

diff --git a/include/linux/padata.h b/include/linux/padata.h
index 113ee626a4dc..0f9e567d5e15 100644
--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -151,7 +151,7 @@ struct parallel_data {
* @flags: padata flags.
*/
struct padata_instance {
- struct notifier_block cpu_notifier;
+ struct hlist_node node;
struct workqueue_struct *wq;
struct parallel_data *pd;
struct padata_cpumask cpumask;
diff --git a/kernel/padata.c b/kernel/padata.c
index 993278895ccc..7848f0566403 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -30,6 +30,7 @@
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/rcupdate.h>
+#include <linux/module.h>

#define MAX_OBJ_NUM 1000

@@ -769,52 +770,43 @@ static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
}

-
-static int padata_cpu_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
{
- int err;
struct padata_instance *pinst;
- int cpu = (unsigned long)hcpu;
+ int ret;

- pinst = container_of(nfb, struct padata_instance, cpu_notifier);
+ pinst = hlist_entry_safe(node, struct padata_instance, node);
+ if (!pinst_has_cpu(pinst, cpu))
+ return 0;

- switch (action) {
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- if (!pinst_has_cpu(pinst, cpu))
- break;
- mutex_lock(&pinst->lock);
- err = __padata_add_cpu(pinst, cpu);
- mutex_unlock(&pinst->lock);
- if (err)
- return notifier_from_errno(err);
- break;
-
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- if (!pinst_has_cpu(pinst, cpu))
- break;
- mutex_lock(&pinst->lock);
- err = __padata_remove_cpu(pinst, cpu);
- mutex_unlock(&pinst->lock);
- if (err)
- return notifier_from_errno(err);
- break;
- }
-
- return NOTIFY_OK;
+ mutex_lock(&pinst->lock);
+ ret = __padata_add_cpu(pinst, cpu);
+ mutex_unlock(&pinst->lock);
+ return ret;
}
+
+static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
+{
+ struct padata_instance *pinst;
+ int ret;
+
+ pinst = hlist_entry_safe(node, struct padata_instance, node);
+ if (!pinst_has_cpu(pinst, cpu))
+ return 0;
+
+ mutex_lock(&pinst->lock);
+ ret = __padata_remove_cpu(pinst, cpu);
+ mutex_unlock(&pinst->lock);
+ return ret;
+}
+
+static enum cpuhp_state hp_online;
#endif

static void __padata_free(struct padata_instance *pinst)
{
#ifdef CONFIG_HOTPLUG_CPU
- unregister_hotcpu_notifier(&pinst->cpu_notifier);
+ cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
#endif

padata_stop(pinst);
@@ -1012,11 +1004,8 @@ struct padata_instance *padata_alloc(struct workqueue_struct *wq,
mutex_init(&pinst->lock);

#ifdef CONFIG_HOTPLUG_CPU
- pinst->cpu_notifier.notifier_call = padata_cpu_callback;
- pinst->cpu_notifier.priority = 0;
- register_hotcpu_notifier(&pinst->cpu_notifier);
+ cpuhp_state_add_instance_nocalls(hp_online, &pinst->node);
#endif
-
return pinst;

err_free_masks:
@@ -1039,3 +1028,26 @@ void padata_free(struct padata_instance *pinst)
kobject_put(&pinst->kobj);
}
EXPORT_SYMBOL(padata_free);
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+static __init int padata_driver_init(void)
+{
+ int ret;
+
+ ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
+ padata_cpu_online,
+ padata_cpu_prep_down);
+ if (ret < 0)
+ return ret;
+ hp_online = ret;
+ return 0;
+}
+module_init(padata_driver_init);
+
+static __exit void padata_driver_exit(void)
+{
+ cpuhp_remove_multi_state(hp_online);
+}
+module_exit(padata_driver_exit);
+#endif
--
2.9.3