[PATCH 16/16] powerpc: mmu nohash: Convert to hotplug state machine

From: Sebastian Andrzej Siewior
Date: Thu Aug 18 2016 - 08:58:50 EST


Install the callbacks via the state machine.

Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
arch/powerpc/mm/mmu_context_nohash.c | 54 +++++++++++++++---------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index 7d95bc402dba..f7755fcbe1f8 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -369,44 +369,34 @@ void destroy_context(struct mm_struct *mm)
}

#ifdef CONFIG_SMP
-
-static int mmu_context_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+static int mmu_ctx_cpu_prepare(unsigned int cpu)
{
- unsigned int cpu = (unsigned int)(long)hcpu;
-
/* We don't touch CPU 0 map, it's allocated at aboot and kept
* around forever
*/
if (cpu == boot_cpuid)
- return NOTIFY_OK;
+ return 0;

- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- pr_devel("MMU: Allocating stale context map for CPU %d\n", cpu);
- stale_map[cpu] = kzalloc(CTX_MAP_SIZE, GFP_KERNEL);
- break;
-#ifdef CONFIG_HOTPLUG_CPU
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu);
- kfree(stale_map[cpu]);
- stale_map[cpu] = NULL;
-
- /* We also clear the cpu_vm_mask bits of CPUs going away */
- clear_tasks_mm_cpumask(cpu);
- break;
-#endif /* CONFIG_HOTPLUG_CPU */
- }
- return NOTIFY_OK;
+ pr_devel("MMU: Allocating stale context map for CPU %d\n", cpu);
+ stale_map[cpu] = kzalloc(CTX_MAP_SIZE, GFP_KERNEL);
+ return 0;
}

-static struct notifier_block mmu_context_cpu_nb = {
- .notifier_call = mmu_context_cpu_notify,
-};
+static int mmu_ctx_cpu_dead(unsigned int cpu)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+ if (cpu == boot_cpuid)
+ return 0;
+
+ pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu);
+ kfree(stale_map[cpu]);
+ stale_map[cpu] = NULL;
+
+ /* We also clear the cpu_vm_mask bits of CPUs going away */
+ clear_tasks_mm_cpumask(cpu);
+#endif
+ return 0;
+}

#endif /* CONFIG_SMP */

@@ -469,7 +459,9 @@ void __init mmu_context_init(void)
#else
stale_map[boot_cpuid] = memblock_virt_alloc(CTX_MAP_SIZE, 0);

- register_cpu_notifier(&mmu_context_cpu_nb);
+ cpuhp_setup_state_nocalls(CPUHP_POWER_MMU_CTX_PREPARE,
+ "POWER_MMU_CTX_PREPARE", mmu_ctx_cpu_prepare,
+ mmu_ctx_cpu_dead);
#endif

printk(KERN_INFO
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 4974c9fdbf9a..92b9cf3271b2 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -33,6 +33,7 @@ enum cpuhp_state {
CPUHP_MD_RAID5_PREPARE,
CPUHP_CPUIDLE_COUPLED_PREPARE,
CPUHP_POWER_PMAC_PREPARE,
+ CPUHP_POWER_MMU_CTX_PREPARE,
CPUHP_NOTIFY_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_BRINGUP_CPU,
--
2.9.3