Commit 9dd333e7 authored by Tobias Huschle's avatar Tobias Huschle Committed by Vasily Gorbik
Browse files

s390/topology: Add sysctl handler for polarization 



Provide an additional path to set the polarization of the system, such
that a user no longer relies on the sysfs interface only and is able
configure the polarization for every reboot via sysctl control files.

The new sysctl can be set as follows:
 - s390.polarization=0 for horizontal polarization
 - s390.polarization=1 for vertical polarization

Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Tested-by: default avatarMete Durlu <meted@linux.ibm.com>
Signed-off-by: default avatarTobias Huschle <huschle@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 307b675c

arch/s390/kernel/topology.c

+45 −13
Original line number Diff line number Diff line
@@ -376,6 +376,25 @@ void topology_expect_change(void) 


static int cpu_management;



static int set_polarization(int polarization)

{

	int rc = 0;



	cpus_read_lock();

	mutex_lock(&smp_cpu_state_mutex);

	if (cpu_management == polarization)

		goto out;

	rc = topology_set_cpu_management(polarization);

	if (rc)

		goto out;

	cpu_management = polarization;

	topology_expect_change();

out:

	mutex_unlock(&smp_cpu_state_mutex);

	cpus_read_unlock();

	return rc;

}



static ssize_t dispatching_show(struct device *dev,

				struct device_attribute *attr,

				char *buf)
@@ -400,19 +419,7 @@ static ssize_t dispatching_store(struct device *dev, 
		return -EINVAL;

	if (val != 0 && val != 1)

		return -EINVAL;

	rc = 0;

	cpus_read_lock();

	mutex_lock(&smp_cpu_state_mutex);

	if (cpu_management == val)

		goto out;

	rc = topology_set_cpu_management(val);

	if (rc)

		goto out;

	cpu_management = val;

	topology_expect_change();

out:

	mutex_unlock(&smp_cpu_state_mutex);

	cpus_read_unlock();

	rc = set_polarization(val);

	return rc ? rc : count;

}

static DEVICE_ATTR_RW(dispatching);
@@ -624,12 +631,37 @@ static int topology_ctl_handler(const struct ctl_table *ctl, int write, 
	return rc;

}



static int polarization_ctl_handler(const struct ctl_table *ctl, int write,

				    void *buffer, size_t *lenp, loff_t *ppos)

{

	int polarization;

	int rc;

	struct ctl_table ctl_entry = {

		.procname	= ctl->procname,

		.data		= &polarization,

		.maxlen		= sizeof(int),

		.extra1		= SYSCTL_ZERO,

		.extra2		= SYSCTL_ONE,

	};



	polarization = cpu_management;

	rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);

	if (rc < 0 || !write)

		return rc;

	return set_polarization(polarization);

}



static struct ctl_table topology_ctl_table[] = {

	{

		.procname	= "topology",

		.mode		= 0644,

		.proc_handler	= topology_ctl_handler,

	},

	{

		.procname	= "polarization",

		.mode		= 0644,

		.proc_handler	= polarization_ctl_handler,

	},

};



static int __init topology_init(void)