[PATCH 12/20] net/iucv: Convert to hotplug state machine

[PATCH 12/20] net/iucv: Convert to hotplug state machine

[Sebastian Andrzej Siewior]

Install the callbacks via the state machine and let the core invoke the
callbacks on the already online CPUs. The smp function calls in the
online/downprep callbacks are not required as the callback is guaranteed to
be invoked on the upcoming/outgoing cpu.

Cc: Ursula Braun <ubraun@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-s390@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 include/linux/cpuhotplug.h |   1 +
 net/iucv/iucv.c            | 118 +++++++++++++++++----------------------------
 2 files changed, 45 insertions(+), 74 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index fd5598b8353a..69abf2c09f6c 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -63,6 +63,7 @@ enum cpuhp_state {
 	CPUHP_X86_THERM_PREPARE,
 	CPUHP_X86_CPUID_PREPARE,
 	CPUHP_X86_MSR_PREPARE,
+	CPUHP_NET_IUCV_PREPARE,
 	CPUHP_TIMERS_DEAD,
 	CPUHP_NOTF_ERR_INJ_PREPARE,
 	CPUHP_MIPS_SOC_PREPARE,
diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index 88a2a3ba4212..f0d6afc5d4a9 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -639,7 +639,7 @@ static void iucv_disable(void)
 	put_online_cpus();
 }
 
-static void free_iucv_data(int cpu)
+static int iucv_cpu_dead(unsigned int cpu)
 {
 	kfree(iucv_param_irq[cpu]);
 	iucv_param_irq[cpu] = NULL;
@@ -647,9 +647,10 @@ static void free_iucv_data(int cpu)
 	iucv_param[cpu] = NULL;
 	kfree(iucv_irq_data[cpu]);
 	iucv_irq_data[cpu] = NULL;
+	return 0;
 }
 
-static int alloc_iucv_data(int cpu)
+static int iucv_cpu_prepare(unsigned int cpu)
 {
 	/* Note: GFP_DMA used to get memory below 2G */
 	iucv_irq_data[cpu] = kmalloc_node(sizeof(struct iucv_irq_data),
@@ -671,58 +672,38 @@ static int alloc_iucv_data(int cpu)
 	return 0;
 
 out_free:
-	free_iucv_data(cpu);
+	iucv_cpu_dead(cpu);
 	return -ENOMEM;
 }
 
-static int iucv_cpu_notify(struct notifier_block *self,
-				     unsigned long action, void *hcpu)
+static int iucv_cpu_online(unsigned int cpu)
 {
-	cpumask_t cpumask;
-	long cpu = (long) hcpu;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		if (alloc_iucv_data(cpu))
-			return notifier_from_errno(-ENOMEM);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		free_iucv_data(cpu);
-		break;
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-	case CPU_DOWN_FAILED:
-	case CPU_DOWN_FAILED_FROZEN:
-		if (!iucv_path_table)
-			break;
-		smp_call_function_single(cpu, iucv_declare_cpu, NULL, 1);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		if (!iucv_path_table)
-			break;
-		cpumask_copy(&cpumask, &iucv_buffer_cpumask);
-		cpumask_clear_cpu(cpu, &cpumask);
-		if (cpumask_empty(&cpumask))
-			/* Can't offline last IUCV enabled cpu. */
-			return notifier_from_errno(-EINVAL);
-		smp_call_function_single(cpu, iucv_retrieve_cpu, NULL, 1);
-		if (cpumask_empty(&iucv_irq_cpumask))
-			smp_call_function_single(
-				cpumask_first(&iucv_buffer_cpumask),
-				iucv_allow_cpu, NULL, 1);
-		break;
-	}
-	return NOTIFY_OK;
+	if (!iucv_path_table)
+		return 0;
+	iucv_declare_cpu(NULL);
+	return 0;
 }
 
-static struct notifier_block __refdata iucv_cpu_notifier = {
-	.notifier_call = iucv_cpu_notify,
-};
+static int iucv_cpu_down_prep(unsigned int cpu)
+{
+	cpumask_t cpumask;
+
+	if (!iucv_path_table)
+		return 0;
+
+	cpumask_copy(&cpumask, &iucv_buffer_cpumask);
+	cpumask_clear_cpu(cpu, &cpumask);
+	if (cpumask_empty(&cpumask))
+		/* Can't offline last IUCV enabled cpu. */
+		return -EINVAL;
+
+	iucv_retrieve_cpu(NULL);
+	if (!cpumask_empty(&iucv_irq_cpumask))
+		return 0;
+	smp_call_function_single(cpumask_first(&iucv_buffer_cpumask),
+				 iucv_allow_cpu, NULL, 1);
+	return 0;
+}
 
 /**
  * iucv_sever_pathid
@@ -2027,6 +2008,7 @@ struct iucv_interface iucv_if = {
 };
 EXPORT_SYMBOL(iucv_if);
 
+static enum cpuhp_state iucv_online;
 /**
  * iucv_init
  *
@@ -2035,7 +2017,6 @@ EXPORT_SYMBOL(iucv_if);
 static int __init iucv_init(void)
 {
 	int rc;
-	int cpu;
 
 	if (!MACHINE_IS_VM) {
 		rc = -EPROTONOSUPPORT;
@@ -2054,23 +2035,19 @@ static int __init iucv_init(void)
 		goto out_int;
 	}
 
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(cpu) {
-		if (alloc_iucv_data(cpu)) {
-			rc = -ENOMEM;
-			goto out_free;
-		}
-	}
-	rc = __register_hotcpu_notifier(&iucv_cpu_notifier);
+	rc = cpuhp_setup_state(CPUHP_NET_IUCV_PREPARE, "net/iucv:prepare",
+			       iucv_cpu_prepare, iucv_cpu_dead);
 	if (rc)
 		goto out_free;
-
-	cpu_notifier_register_done();
+	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "net/iucv:online",
+			       iucv_cpu_online, iucv_cpu_down_prep);
+	if (rc < 0)
+		goto out_free;
+	iucv_online = rc;
 
 	rc = register_reboot_notifier(&iucv_reboot_notifier);
 	if (rc)
-		goto out_cpu;
+		goto out_free;
 	ASCEBC(iucv_error_no_listener, 16);
 	ASCEBC(iucv_error_no_memory, 16);
 	ASCEBC(iucv_error_pathid, 16);
@@ -2084,14 +2061,10 @@ static int __init iucv_init(void)
 
 out_reboot:
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-out_cpu:
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
 out_free:
-	for_each_possible_cpu(cpu)
-		free_iucv_data(cpu);
-
-	cpu_notifier_register_done();
+	if (iucv_online)
+		cpuhp_remove_state(iucv_online);
+	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
 
 	root_device_unregister(iucv_root);
 out_int:
@@ -2110,7 +2083,6 @@ static int __init iucv_init(void)
 static void __exit iucv_exit(void)
 {
 	struct iucv_irq_list *p, *n;
-	int cpu;
 
 	spin_lock_irq(&iucv_queue_lock);
 	list_for_each_entry_safe(p, n, &iucv_task_queue, list)
@@ -2119,11 +2091,9 @@ static void __exit iucv_exit(void)
 		kfree(p);
 	spin_unlock_irq(&iucv_queue_lock);
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
-	for_each_possible_cpu(cpu)
-		free_iucv_data(cpu);
-	cpu_notifier_register_done();
+
+	cpuhp_remove_state_nocalls(iucv_online);
+	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
 	root_device_unregister(iucv_root);
 	bus_unregister(&iucv_bus);
 	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);
-- 
2.10.2

Re: [PATCH 12/20] net/iucv: Convert to hotplug state machine

[Ursula Braun]

Sebastian,

your patch looks good to me. I run successfully some small tests with it.
I want to suggest a small change in iucv_init() to keep the uniform technique
of undo labels below. Do you agree?

Kind regards, Ursula

On 11/17/2016 07:35 PM, Sebastian Andrzej Siewior wrote:
> Install the callbacks via the state machine and let the core invoke the
> callbacks on the already online CPUs. The smp function calls in the
> online/downprep callbacks are not required as the callback is guaranteed to
> be invoked on the upcoming/outgoing cpu.
> 
> Cc: Ursula Braun <ubraun@linux.vnet.ibm.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: linux-s390@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  include/linux/cpuhotplug.h |   1 +
>  net/iucv/iucv.c            | 118 +++++++++++++++++----------------------------
>  2 files changed, 45 insertions(+), 74 deletions(-)
> 
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index fd5598b8353a..69abf2c09f6c 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -63,6 +63,7 @@ enum cpuhp_state {
>  	CPUHP_X86_THERM_PREPARE,
>  	CPUHP_X86_CPUID_PREPARE,
>  	CPUHP_X86_MSR_PREPARE,
> +	CPUHP_NET_IUCV_PREPARE,
>  	CPUHP_TIMERS_DEAD,
>  	CPUHP_NOTF_ERR_INJ_PREPARE,
>  	CPUHP_MIPS_SOC_PREPARE,
> diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
> index 88a2a3ba4212..f0d6afc5d4a9 100644
> --- a/net/iucv/iucv.c
> +++ b/net/iucv/iucv.c
> @@ -639,7 +639,7 @@ static void iucv_disable(void)
>  	put_online_cpus();
>  }
>  
> -static void free_iucv_data(int cpu)
> +static int iucv_cpu_dead(unsigned int cpu)
>  {
>  	kfree(iucv_param_irq[cpu]);
>  	iucv_param_irq[cpu] = NULL;
> @@ -647,9 +647,10 @@ static void free_iucv_data(int cpu)
>  	iucv_param[cpu] = NULL;
>  	kfree(iucv_irq_data[cpu]);
>  	iucv_irq_data[cpu] = NULL;
> +	return 0;
>  }
>  
> -static int alloc_iucv_data(int cpu)
> +static int iucv_cpu_prepare(unsigned int cpu)
>  {
>  	/* Note: GFP_DMA used to get memory below 2G */
>  	iucv_irq_data[cpu] = kmalloc_node(sizeof(struct iucv_irq_data),
> @@ -671,58 +672,38 @@ static int alloc_iucv_data(int cpu)
>  	return 0;
>  
>  out_free:
> -	free_iucv_data(cpu);
> +	iucv_cpu_dead(cpu);
>  	return -ENOMEM;
>  }
>  
> -static int iucv_cpu_notify(struct notifier_block *self,
> -				     unsigned long action, void *hcpu)
> +static int iucv_cpu_online(unsigned int cpu)
>  {
> -	cpumask_t cpumask;
> -	long cpu = (long) hcpu;
> -
> -	switch (action) {
> -	case CPU_UP_PREPARE:
> -	case CPU_UP_PREPARE_FROZEN:
> -		if (alloc_iucv_data(cpu))
> -			return notifier_from_errno(-ENOMEM);
> -		break;
> -	case CPU_UP_CANCELED:
> -	case CPU_UP_CANCELED_FROZEN:
> -	case CPU_DEAD:
> -	case CPU_DEAD_FROZEN:
> -		free_iucv_data(cpu);
> -		break;
> -	case CPU_ONLINE:
> -	case CPU_ONLINE_FROZEN:
> -	case CPU_DOWN_FAILED:
> -	case CPU_DOWN_FAILED_FROZEN:
> -		if (!iucv_path_table)
> -			break;
> -		smp_call_function_single(cpu, iucv_declare_cpu, NULL, 1);
> -		break;
> -	case CPU_DOWN_PREPARE:
> -	case CPU_DOWN_PREPARE_FROZEN:
> -		if (!iucv_path_table)
> -			break;
> -		cpumask_copy(&cpumask, &iucv_buffer_cpumask);
> -		cpumask_clear_cpu(cpu, &cpumask);
> -		if (cpumask_empty(&cpumask))
> -			/* Can't offline last IUCV enabled cpu. */
> -			return notifier_from_errno(-EINVAL);
> -		smp_call_function_single(cpu, iucv_retrieve_cpu, NULL, 1);
> -		if (cpumask_empty(&iucv_irq_cpumask))
> -			smp_call_function_single(
> -				cpumask_first(&iucv_buffer_cpumask),
> -				iucv_allow_cpu, NULL, 1);
> -		break;
> -	}
> -	return NOTIFY_OK;
> +	if (!iucv_path_table)
> +		return 0;
> +	iucv_declare_cpu(NULL);
> +	return 0;
>  }
>  
> -static struct notifier_block __refdata iucv_cpu_notifier = {
> -	.notifier_call = iucv_cpu_notify,
> -};
> +static int iucv_cpu_down_prep(unsigned int cpu)
> +{
> +	cpumask_t cpumask;
> +
> +	if (!iucv_path_table)
> +		return 0;
> +
> +	cpumask_copy(&cpumask, &iucv_buffer_cpumask);
> +	cpumask_clear_cpu(cpu, &cpumask);
> +	if (cpumask_empty(&cpumask))
> +		/* Can't offline last IUCV enabled cpu. */
> +		return -EINVAL;
> +
> +	iucv_retrieve_cpu(NULL);
> +	if (!cpumask_empty(&iucv_irq_cpumask))
> +		return 0;
> +	smp_call_function_single(cpumask_first(&iucv_buffer_cpumask),
> +				 iucv_allow_cpu, NULL, 1);
> +	return 0;
> +}
>  
>  /**
>   * iucv_sever_pathid
> @@ -2027,6 +2008,7 @@ struct iucv_interface iucv_if = {
>  };
>  EXPORT_SYMBOL(iucv_if);
>  
> +static enum cpuhp_state iucv_online;
>  /**
>   * iucv_init
>   *
> @@ -2035,7 +2017,6 @@ EXPORT_SYMBOL(iucv_if);
>  static int __init iucv_init(void)
>  {
>  	int rc;
> -	int cpu;
>  
>  	if (!MACHINE_IS_VM) {
>  		rc = -EPROTONOSUPPORT;
> @@ -2054,23 +2035,19 @@ static int __init iucv_init(void)
>  		goto out_int;
>  	}
>  
> -	cpu_notifier_register_begin();
> -
> -	for_each_online_cpu(cpu) {
> -		if (alloc_iucv_data(cpu)) {
> -			rc = -ENOMEM;
> -			goto out_free;
> -		}
> -	}
> -	rc = __register_hotcpu_notifier(&iucv_cpu_notifier);
> +	rc = cpuhp_setup_state(CPUHP_NET_IUCV_PREPARE, "net/iucv:prepare",
> +			       iucv_cpu_prepare, iucv_cpu_dead);
>  	if (rc)
>  		goto out_free;
> -
> -	cpu_notifier_register_done();
> +	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "net/iucv:online",
> +			       iucv_cpu_online, iucv_cpu_down_prep);
> +	if (rc < 0)
> +		goto out_free;
> +	iucv_online = rc;
>  
>  	rc = register_reboot_notifier(&iucv_reboot_notifier);
>  	if (rc)
> -		goto out_cpu;
> +		goto out_free;
>  	ASCEBC(iucv_error_no_listener, 16);
>  	ASCEBC(iucv_error_no_memory, 16);
>  	ASCEBC(iucv_error_pathid, 16);
> @@ -2084,14 +2061,10 @@ static int __init iucv_init(void)
>  
>  out_reboot:
>  	unregister_reboot_notifier(&iucv_reboot_notifier);
> -out_cpu:
> -	cpu_notifier_register_begin();
> -	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
>  out_free:
> -	for_each_possible_cpu(cpu)
> -		free_iucv_data(cpu);
> -
> -	cpu_notifier_register_done();
> +	if (iucv_online)
> +		cpuhp_remove_state(iucv_online);
> +	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
>  
>  	root_device_unregister(iucv_root);
>  out_int:
I prefer to keep the technique of cascaded undo labels here, like this:
@@ -2054,23 +2035,19 @@ static int __init iucv_init(void)
                goto out_int;
        }
 
-       cpu_notifier_register_begin();
-
-       for_each_online_cpu(cpu) {
-               if (alloc_iucv_data(cpu)) {
-                       rc = -ENOMEM;
-                       goto out_free;
-               }
-       }
-       rc = __register_hotcpu_notifier(&iucv_cpu_notifier);
+       rc = cpuhp_setup_state(CPUHP_NET_IUCV_PREPARE, "net/iucv:prepare",
+                              iucv_cpu_prepare, iucv_cpu_dead);
        if (rc)
-               goto out_free;
-
-       cpu_notifier_register_done();
+               goto out_dev;
+       rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "net/iucv:online",
+                              iucv_cpu_online, iucv_cpu_down_prep);
+       if (rc < 0)
+               goto out_prep;
+       iucv_online = rc;
 
        rc = register_reboot_notifier(&iucv_reboot_notifier);
        if (rc)
-               goto out_cpu;
+               goto out_remove;
        ASCEBC(iucv_error_no_listener, 16);
        ASCEBC(iucv_error_no_memory, 16);
        ASCEBC(iucv_error_pathid, 16);
@@ -2084,15 +2061,12 @@ static int __init iucv_init(void)
 
 out_reboot:
        unregister_reboot_notifier(&iucv_reboot_notifier);
-out_cpu:
-       cpu_notifier_register_begin();
-       __unregister_hotcpu_notifier(&iucv_cpu_notifier);
-out_free:
-       for_each_possible_cpu(cpu)
-               free_iucv_data(cpu);
-
-       cpu_notifier_register_done();
-
+out_remove:
+       if (iucv_online)
+               cpuhp_remove_state(iucv_online);
+out_prep:
+       cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
+out_dev:
        root_device_unregister(iucv_root);
 out_int:
        unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);

> @@ -2110,7 +2083,6 @@ static int __init iucv_init(void)
>  static void __exit iucv_exit(void)
>  {
>  	struct iucv_irq_list *p, *n;
> -	int cpu;
>  
>  	spin_lock_irq(&iucv_queue_lock);
>  	list_for_each_entry_safe(p, n, &iucv_task_queue, list)
> @@ -2119,11 +2091,9 @@ static void __exit iucv_exit(void)
>  		kfree(p);
>  	spin_unlock_irq(&iucv_queue_lock);
>  	unregister_reboot_notifier(&iucv_reboot_notifier);
> -	cpu_notifier_register_begin();
> -	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
> -	for_each_possible_cpu(cpu)
> -		free_iucv_data(cpu);
> -	cpu_notifier_register_done();
> +
> +	cpuhp_remove_state_nocalls(iucv_online);
> +	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
>  	root_device_unregister(iucv_root);
>  	bus_unregister(&iucv_bus);
>  	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);
> 

Re: [PATCH 12/20] net/iucv: Convert to hotplug state machine

[Sebastian Andrzej Siewior]

On 2016-11-23 19:04:16 [+0100], Ursula Braun wrote:
> Sebastian,
Hallo Ursula,

> your patch looks good to me. I run successfully some small tests with it.
> I want to suggest a small change in iucv_init() to keep the uniform technique
> of undo labels below. Do you agree?

So what you ask for is:

diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index f0d6afc5d4a9..8f7ef167c45a 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -2038,16 +2038,16 @@ static int __init iucv_init(void)
 	rc = cpuhp_setup_state(CPUHP_NET_IUCV_PREPARE, "net/iucv:prepare",
 			       iucv_cpu_prepare, iucv_cpu_dead);
 	if (rc)
-		goto out_free;
+		goto out_dev;
 	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "net/iucv:online",
 			       iucv_cpu_online, iucv_cpu_down_prep);
 	if (rc < 0)
-		goto out_free;
+		goto out_prep;
 	iucv_online = rc;
 
 	rc = register_reboot_notifier(&iucv_reboot_notifier);
 	if (rc)
-		goto out_free;
+		goto out_remove_hp;
 	ASCEBC(iucv_error_no_listener, 16);
 	ASCEBC(iucv_error_no_memory, 16);
 	ASCEBC(iucv_error_pathid, 16);
@@ -2061,11 +2061,11 @@ static int __init iucv_init(void)
 
 out_reboot:
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-out_free:
-	if (iucv_online)
-		cpuhp_remove_state(iucv_online);
+out_remove_hp:
+	cpuhp_remove_state(iucv_online);
+out_prep:
 	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
-
+out_dev:
 	root_device_unregister(iucv_root);
 out_int:
 	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);

This is your change including the removal of the `if' check in the
`out_remove' label which got renamed to `out_remove_hp'.
Of course, I agree with this change and a proper patch will follow in a
few hours if nobody objects.

> Kind regards, Ursula

Sebastian

[PATCH 12/20 v2] net/iucv: Convert to hotplug state machine

[Sebastian Andrzej Siewior]

Install the callbacks via the state machine and let the core invoke the
callbacks on the already online CPUs. The smp function calls in the
online/downprep callbacks are not required as the callback is guaranteed to
be invoked on the upcoming/outgoing cpu.

Cc: Ursula Braun <ubraun@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-s390@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
v1…v2: Use explicit labels for clean up in iucv_init() as suggested by
       Ursula.

 include/linux/cpuhotplug.h |    1 
 net/iucv/iucv.c            |  122 ++++++++++++++++-----------------------------
 2 files changed, 47 insertions(+), 76 deletions(-)

--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -63,6 +63,7 @@ enum cpuhp_state {
 	CPUHP_X86_THERM_PREPARE,
 	CPUHP_X86_CPUID_PREPARE,
 	CPUHP_X86_MSR_PREPARE,
+	CPUHP_NET_IUCV_PREPARE,
 	CPUHP_TIMERS_DEAD,
 	CPUHP_NOTF_ERR_INJ_PREPARE,
 	CPUHP_MIPS_SOC_PREPARE,
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -639,7 +639,7 @@ static void iucv_disable(void)
 	put_online_cpus();
 }
 
-static void free_iucv_data(int cpu)
+static int iucv_cpu_dead(unsigned int cpu)
 {
 	kfree(iucv_param_irq[cpu]);
 	iucv_param_irq[cpu] = NULL;
@@ -647,9 +647,10 @@ static void free_iucv_data(int cpu)
 	iucv_param[cpu] = NULL;
 	kfree(iucv_irq_data[cpu]);
 	iucv_irq_data[cpu] = NULL;
+	return 0;
 }
 
-static int alloc_iucv_data(int cpu)
+static int iucv_cpu_prepare(unsigned int cpu)
 {
 	/* Note: GFP_DMA used to get memory below 2G */
 	iucv_irq_data[cpu] = kmalloc_node(sizeof(struct iucv_irq_data),
@@ -671,58 +672,38 @@ static int alloc_iucv_data(int cpu)
 	return 0;
 
 out_free:
-	free_iucv_data(cpu);
+	iucv_cpu_dead(cpu);
 	return -ENOMEM;
 }
 
-static int iucv_cpu_notify(struct notifier_block *self,
-				     unsigned long action, void *hcpu)
+static int iucv_cpu_online(unsigned int cpu)
+{
+	if (!iucv_path_table)
+		return 0;
+	iucv_declare_cpu(NULL);
+	return 0;
+}
+
+static int iucv_cpu_down_prep(unsigned int cpu)
 {
 	cpumask_t cpumask;
-	long cpu = (long) hcpu;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		if (alloc_iucv_data(cpu))
-			return notifier_from_errno(-ENOMEM);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		free_iucv_data(cpu);
-		break;
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-	case CPU_DOWN_FAILED:
-	case CPU_DOWN_FAILED_FROZEN:
-		if (!iucv_path_table)
-			break;
-		smp_call_function_single(cpu, iucv_declare_cpu, NULL, 1);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		if (!iucv_path_table)
-			break;
-		cpumask_copy(&cpumask, &iucv_buffer_cpumask);
-		cpumask_clear_cpu(cpu, &cpumask);
-		if (cpumask_empty(&cpumask))
-			/* Can't offline last IUCV enabled cpu. */
-			return notifier_from_errno(-EINVAL);
-		smp_call_function_single(cpu, iucv_retrieve_cpu, NULL, 1);
-		if (cpumask_empty(&iucv_irq_cpumask))
-			smp_call_function_single(
-				cpumask_first(&iucv_buffer_cpumask),
-				iucv_allow_cpu, NULL, 1);
-		break;
-	}
-	return NOTIFY_OK;
-}
+	if (!iucv_path_table)
+		return 0;
 
-static struct notifier_block __refdata iucv_cpu_notifier = {
-	.notifier_call = iucv_cpu_notify,
-};
+	cpumask_copy(&cpumask, &iucv_buffer_cpumask);
+	cpumask_clear_cpu(cpu, &cpumask);
+	if (cpumask_empty(&cpumask))
+		/* Can't offline last IUCV enabled cpu. */
+		return -EINVAL;
+
+	iucv_retrieve_cpu(NULL);
+	if (!cpumask_empty(&iucv_irq_cpumask))
+		return 0;
+	smp_call_function_single(cpumask_first(&iucv_buffer_cpumask),
+				 iucv_allow_cpu, NULL, 1);
+	return 0;
+}
 
 /**
  * iucv_sever_pathid
@@ -2027,6 +2008,7 @@ struct iucv_interface iucv_if = {
 };
 EXPORT_SYMBOL(iucv_if);
 
+static enum cpuhp_state iucv_online;
 /**
  * iucv_init
  *
@@ -2035,7 +2017,6 @@ EXPORT_SYMBOL(iucv_if);
 static int __init iucv_init(void)
 {
 	int rc;
-	int cpu;
 
 	if (!MACHINE_IS_VM) {
 		rc = -EPROTONOSUPPORT;
@@ -2054,23 +2035,19 @@ static int __init iucv_init(void)
 		goto out_int;
 	}
 
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(cpu) {
-		if (alloc_iucv_data(cpu)) {
-			rc = -ENOMEM;
-			goto out_free;
-		}
-	}
-	rc = __register_hotcpu_notifier(&iucv_cpu_notifier);
+	rc = cpuhp_setup_state(CPUHP_NET_IUCV_PREPARE, "net/iucv:prepare",
+			       iucv_cpu_prepare, iucv_cpu_dead);
 	if (rc)
-		goto out_free;
-
-	cpu_notifier_register_done();
+		goto out_dev;
+	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "net/iucv:online",
+			       iucv_cpu_online, iucv_cpu_down_prep);
+	if (rc < 0)
+		goto out_prep;
+	iucv_online = rc;
 
 	rc = register_reboot_notifier(&iucv_reboot_notifier);
 	if (rc)
-		goto out_cpu;
+		goto out_remove_hp;
 	ASCEBC(iucv_error_no_listener, 16);
 	ASCEBC(iucv_error_no_memory, 16);
 	ASCEBC(iucv_error_pathid, 16);
@@ -2084,15 +2061,11 @@ static int __init iucv_init(void)
 
 out_reboot:
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-out_cpu:
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
-out_free:
-	for_each_possible_cpu(cpu)
-		free_iucv_data(cpu);
-
-	cpu_notifier_register_done();
-
+out_remove_hp:
+	cpuhp_remove_state(iucv_online);
+out_prep:
+	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
+out_dev:
 	root_device_unregister(iucv_root);
 out_int:
 	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);
@@ -2110,7 +2083,6 @@ static int __init iucv_init(void)
 static void __exit iucv_exit(void)
 {
 	struct iucv_irq_list *p, *n;
-	int cpu;
 
 	spin_lock_irq(&iucv_queue_lock);
 	list_for_each_entry_safe(p, n, &iucv_task_queue, list)
@@ -2119,11 +2091,9 @@ static void __exit iucv_exit(void)
 		kfree(p);
 	spin_unlock_irq(&iucv_queue_lock);
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
-	for_each_possible_cpu(cpu)
-		free_iucv_data(cpu);
-	cpu_notifier_register_done();
+
+	cpuhp_remove_state_nocalls(iucv_online);
+	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
 	root_device_unregister(iucv_root);
 	bus_unregister(&iucv_bus);
 	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);

[PATCH] net/iucv: use explicit clean up labels in iucv_init()

[Sebastian Andrzej Siewior]

Ursula suggested to use explicit labels for clean up in the error path
instead of one `out_free' label which handles multiple exits.
Since the previous patch got already applied, here is a follow up patch.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 net/iucv/iucv.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index f0d6afc5d4a9..8f7ef167c45a 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -2038,16 +2038,16 @@ static int __init iucv_init(void)
 	rc = cpuhp_setup_state(CPUHP_NET_IUCV_PREPARE, "net/iucv:prepare",
 			       iucv_cpu_prepare, iucv_cpu_dead);
 	if (rc)
-		goto out_free;
+		goto out_dev;
 	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "net/iucv:online",
 			       iucv_cpu_online, iucv_cpu_down_prep);
 	if (rc < 0)
-		goto out_free;
+		goto out_prep;
 	iucv_online = rc;
 
 	rc = register_reboot_notifier(&iucv_reboot_notifier);
 	if (rc)
-		goto out_free;
+		goto out_remove_hp;
 	ASCEBC(iucv_error_no_listener, 16);
 	ASCEBC(iucv_error_no_memory, 16);
 	ASCEBC(iucv_error_pathid, 16);
@@ -2061,11 +2061,11 @@ static int __init iucv_init(void)
 
 out_reboot:
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-out_free:
-	if (iucv_online)
-		cpuhp_remove_state(iucv_online);
+out_remove_hp:
+	cpuhp_remove_state(iucv_online);
+out_prep:
 	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
-
+out_dev:
 	root_device_unregister(iucv_root);
 out_int:
 	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);
-- 
2.10.2

Re: [PATCH] net/iucv: use explicit clean up labels in iucv_init()

[David Miller]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 24 Nov 2016 17:10:13 +0100

> Ursula suggested to use explicit labels for clean up in the error path
> instead of one `out_free' label which handles multiple exits.
> Since the previous patch got already applied, here is a follow up patch.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

"Previous patch" doesn't tell readers anything specific enough to identify
the change you are referring to.  This will be even more true years down
the line if someone tries to read this commit and figure out what you
are referring to.

We have a standard mechanism to refer to commits, via SHA1_ID and commit
header line text, please use it.

Thank you.

Re: [PATCH] net/iucv: use explicit clean up labels in iucv_init()

[Thomas Gleixner]

On Mon, 28 Nov 2016, David Miller wrote:
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Date: Thu, 24 Nov 2016 17:10:13 +0100
> 
> > Ursula suggested to use explicit labels for clean up in the error path
> > instead of one `out_free' label which handles multiple exits.
> > Since the previous patch got already applied, here is a follow up patch.
> > 
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> 
> "Previous patch" doesn't tell readers anything specific enough to identify
> the change you are referring to.  This will be even more true years down
> the line if someone tries to read this commit and figure out what you
> are referring to.
> 
> We have a standard mechanism to refer to commits, via SHA1_ID and commit
> header line text, please use it.

I amended the commit message.

Thanks,

	tglx