Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the final round of converting the notifier mess to the state
  machine. The removal of the notifiers and the related infrastructure
  will happen around rc1, as there are conversions outstanding in other
  trees.

  The whole exercise removed about 2000 lines of code in total and in
  course of the conversion several dozen bugs got fixed. The new
  mechanism allows to test almost every hotplug step standalone, so
  usage sites can exercise all transitions extensively.

  There is more room for improvement, like integrating all the
  pointlessly different architecture mechanisms of synchronizing,
  setting cpus online etc into the core code"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  tracing/rb: Init the CPU mask on allocation
  soc/fsl/qbman: Convert to hotplug state machine
  soc/fsl/qbman: Convert to hotplug state machine
  zram: Convert to hotplug state machine
  KVM/PPC/Book3S HV: Convert to hotplug state machine
  arm64/cpuinfo: Convert to hotplug state machine
  arm64/cpuinfo: Make hotplug notifier symmetric
  mm/compaction: Convert to hotplug state machine
  iommu/vt-d: Convert to hotplug state machine
  mm/zswap: Convert pool to hotplug state machine
  mm/zswap: Convert dst-mem to hotplug state machine
  mm/zsmalloc: Convert to hotplug state machine
  mm/vmstat: Convert to hotplug state machine
  mm/vmstat: Avoid on each online CPU loops
  mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead()
  tracing/rb: Convert to hotplug state machine
  oprofile/nmi timer: Convert to hotplug state machine
  net/iucv: Use explicit clean up labels in iucv_init()
  x86/pci/amd-bus: Convert to hotplug state machine
  x86/oprofile/nmi: Convert to hotplug state machine
  ...

1 files changed, 51 insertions, 121 deletions

diff --git a/mm/zswap.c b/mm/zswap.c
index 275b22cc8df4..067a0d62f318 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -118,7 +118,7 @@ struct zswap_pool {
 	struct kref kref;
 	struct list_head list;
 	struct work_struct work;
-	struct notifier_block notifier;
+	struct hlist_node node;
 	char tfm_name[CRYPTO_MAX_ALG_NAME];
 };
 
@@ -352,143 +352,58 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
 **********************************/
 static DEFINE_PER_CPU(u8 *, zswap_dstmem);
 
-static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
+static int zswap_dstmem_prepare(unsigned int cpu)
 {
 	u8 *dst;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-		dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
-		if (!dst) {
-			pr_err("can't allocate compressor buffer\n");
-			return NOTIFY_BAD;
-		}
-		per_cpu(zswap_dstmem, cpu) = dst;
-		break;
-	case CPU_DEAD:
-	case CPU_UP_CANCELED:
-		dst = per_cpu(zswap_dstmem, cpu);
-		kfree(dst);
-		per_cpu(zswap_dstmem, cpu) = NULL;
-		break;
-	default:
-		break;
+	dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
+	if (!dst) {
+		pr_err("can't allocate compressor buffer\n");
+		return -ENOMEM;
 	}
-	return NOTIFY_OK;
+	per_cpu(zswap_dstmem, cpu) = dst;
+	return 0;
 }
 
-static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
-				     unsigned long action, void *pcpu)
+static int zswap_dstmem_dead(unsigned int cpu)
 {
-	return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
-}
+	u8 *dst;
 
-static struct notifier_block zswap_dstmem_notifier = {
-	.notifier_call =	zswap_cpu_dstmem_notifier,
-};
+	dst = per_cpu(zswap_dstmem, cpu);
+	kfree(dst);
+	per_cpu(zswap_dstmem, cpu) = NULL;
 
-static int __init zswap_cpu_dstmem_init(void)
-{
-	unsigned long cpu;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
-		    NOTIFY_BAD)
-			goto cleanup;
-	__register_cpu_notifier(&zswap_dstmem_notifier);
-	cpu_notifier_register_done();
 	return 0;
-
-cleanup:
-	for_each_online_cpu(cpu)
-		__zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-	cpu_notifier_register_done();
-	return -ENOMEM;
-}
-
-static void zswap_cpu_dstmem_destroy(void)
-{
-	unsigned long cpu;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		__zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-	__unregister_cpu_notifier(&zswap_dstmem_notifier);
-	cpu_notifier_register_done();
 }
 
-static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
-				     unsigned long action, unsigned long cpu)
+static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
 {
+	struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
 	struct crypto_comp *tfm;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-		if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
-			break;
-		tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
-		if (IS_ERR_OR_NULL(tfm)) {
-			pr_err("could not alloc crypto comp %s : %ld\n",
-			       pool->tfm_name, PTR_ERR(tfm));
-			return NOTIFY_BAD;
-		}
-		*per_cpu_ptr(pool->tfm, cpu) = tfm;
-		break;
-	case CPU_DEAD:
-	case CPU_UP_CANCELED:
-		tfm = *per_cpu_ptr(pool->tfm, cpu);
-		if (!IS_ERR_OR_NULL(tfm))
-			crypto_free_comp(tfm);
-		*per_cpu_ptr(pool->tfm, cpu) = NULL;
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static int zswap_cpu_comp_notifier(struct notifier_block *nb,
-				   unsigned long action, void *pcpu)
-{
-	unsigned long cpu = (unsigned long)pcpu;
-	struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
-
-	return __zswap_cpu_comp_notifier(pool, action, cpu);
-}
+	if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
+		return 0;
 
-static int zswap_cpu_comp_init(struct zswap_pool *pool)
-{
-	unsigned long cpu;
-
-	memset(&pool->notifier, 0, sizeof(pool->notifier));
-	pool->notifier.notifier_call = zswap_cpu_comp_notifier;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
-		    NOTIFY_BAD)
-			goto cleanup;
-	__register_cpu_notifier(&pool->notifier);
-	cpu_notifier_register_done();
+	tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
+	if (IS_ERR_OR_NULL(tfm)) {
+		pr_err("could not alloc crypto comp %s : %ld\n",
+		       pool->tfm_name, PTR_ERR(tfm));
+		return -ENOMEM;
+	}
+	*per_cpu_ptr(pool->tfm, cpu) = tfm;
 	return 0;
-
-cleanup:
-	for_each_online_cpu(cpu)
-		__zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
-	cpu_notifier_register_done();
-	return -ENOMEM;
 }
 
-static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
+static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
 {
-	unsigned long cpu;
+	struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
+	struct crypto_comp *tfm;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		__zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
-	__unregister_cpu_notifier(&pool->notifier);
-	cpu_notifier_register_done();
+	tfm = *per_cpu_ptr(pool->tfm, cpu);
+	if (!IS_ERR_OR_NULL(tfm))
+		crypto_free_comp(tfm);
+	*per_cpu_ptr(pool->tfm, cpu) = NULL;
+	return 0;
 }
 
 /*********************************
@@ -569,6 +484,7 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
 	struct zswap_pool *pool;
 	char name[38]; /* 'zswap' + 32 char (max) num + \0 */
 	gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
+	int ret;
 
 	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 	if (!pool) {
@@ -593,7 +509,9 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
 		goto error;
 	}
 
-	if (zswap_cpu_comp_init(pool))
+	ret = cpuhp_state_add_instance(CPUHP_MM_ZSWP_POOL_PREPARE,
+				       &pool->node);
+	if (ret)
 		goto error;
 	pr_debug("using %s compressor\n", pool->tfm_name);
 
@@ -647,7 +565,7 @@ static void zswap_pool_destroy(struct zswap_pool *pool)
 {
 	zswap_pool_debug("destroying", pool);
 
-	zswap_cpu_comp_destroy(pool);
+	cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node);
 	free_percpu(pool->tfm);
 	zpool_destroy_pool(pool->zpool);
 	kfree(pool);
@@ -1238,6 +1156,7 @@ static void __exit zswap_debugfs_exit(void) { }
 static int __init init_zswap(void)
 {
 	struct zswap_pool *pool;
+	int ret;
 
 	zswap_init_started = true;
 
@@ -1246,11 +1165,20 @@ static int __init init_zswap(void)
 		goto cache_fail;
 	}
 
-	if (zswap_cpu_dstmem_init()) {
+	ret = cpuhp_setup_state(CPUHP_MM_ZSWP_MEM_PREPARE, "mm/zswap:prepare",
+				zswap_dstmem_prepare, zswap_dstmem_dead);
+	if (ret) {
 		pr_err("dstmem alloc failed\n");
 		goto dstmem_fail;
 	}
 
+	ret = cpuhp_setup_state_multi(CPUHP_MM_ZSWP_POOL_PREPARE,
+				      "mm/zswap_pool:prepare",
+				      zswap_cpu_comp_prepare,
+				      zswap_cpu_comp_dead);
+	if (ret)
+		goto hp_fail;
+
 	pool = __zswap_pool_create_fallback();
 	if (!pool) {
 		pr_err("pool creation failed\n");
@@ -1267,7 +1195,9 @@ static int __init init_zswap(void)
 	return 0;
 
 pool_fail:
-	zswap_cpu_dstmem_destroy();
+	cpuhp_remove_state_nocalls(CPUHP_MM_ZSWP_POOL_PREPARE);
+hp_fail:
+	cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE);
 dstmem_fail:
 	zswap_entry_cache_destroy();
 cache_fail: