drivers base/cacheinfo: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs. No functional change.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161103145021.28528-13-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 16 insertions, 43 deletions

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index e9fd32e91668..47983a2ba621 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -498,57 +498,30 @@ err:
         return rc;
 }
 
-static void cache_remove_dev(unsigned int cpu)
+static int cacheinfo_cpu_online(unsigned int cpu)
 {
-        if (!cpumask_test_cpu(cpu, &cache_dev_map))
-                return;
-        cpumask_clear_cpu(cpu, &cache_dev_map);
+        int rc = detect_cache_attributes(cpu);
 
-        cpu_cache_sysfs_exit(cpu);
+        if (rc)
+                return rc;
+        rc = cache_add_dev(cpu);
+        if (rc)
+                free_cache_attributes(cpu);
+        return rc;
 }
 
-static int cacheinfo_cpu_callback(struct notifier_block *nfb,
-                                  unsigned long action, void *hcpu)
+static int cacheinfo_cpu_pre_down(unsigned int cpu)
 {
-        unsigned int cpu = (unsigned long)hcpu;
-        int rc = 0;
-
-        switch (action & ~CPU_TASKS_FROZEN) {
-        case CPU_ONLINE:
-                rc = detect_cache_attributes(cpu);
-                if (!rc)
-                        rc = cache_add_dev(cpu);
-                break;
-        case CPU_DEAD:
-                cache_remove_dev(cpu);
-                free_cache_attributes(cpu);
-                break;
-        }
-        return notifier_from_errno(rc);
+        if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
+                cpu_cache_sysfs_exit(cpu);
+
+        free_cache_attributes(cpu);
+        return 0;
 }
 
 static int __init cacheinfo_sysfs_init(void)
 {
-        int cpu, rc = 0;
-
-        cpu_notifier_register_begin();
-
-        for_each_online_cpu(cpu) {
-                rc = detect_cache_attributes(cpu);
-                if (rc)
-                        goto out;
-                rc = cache_add_dev(cpu);
-                if (rc) {
-                        free_cache_attributes(cpu);
-                        pr_err("error populating cacheinfo..cpu%d\n", cpu);
-                        goto out;
-                }
-        }
-        __hotcpu_notifier(cacheinfo_cpu_callback, 0);
-
-out:
-        cpu_notifier_register_done();
-        return rc;
+        return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "base/cacheinfo:online",
+                                 cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
 }
-
 device_initcall(cacheinfo_sysfs_init);