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Commit 196851be authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Martin Schwidefsky
Browse files

s390/topology: correct topology mode proc handler 



Reuse proc_douintvec_minmax to simplify topology mode proc handler.
This also enforces correct range of 0-1 on proc writes and correctly
handles numbers starting with 0 or spaces.

Before:
$ echo 01 > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
0
$ echo ' 1' > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo 2 > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo 12 > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
1

After:
$ echo 01 > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
1
$ echo ' 1' > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
1
$ echo 2 > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo 12 > /proc/sys/s390/topology
-bash: echo: write error: Invalid argument
$ echo '   0' > /proc/sys/s390/topology
$ cat /proc/sys/s390/topology
0

Reviewed-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f149371e

arch/s390/kernel/topology.c

+18 −25
Original line number Diff line number Diff line
@@ -579,40 +579,33 @@ early_param("topology", topology_setup); 
static int topology_ctl_handler(struct ctl_table *ctl, int write,

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

{

	unsigned int len;

	int enabled = topology_is_enabled();

	int new_mode;

	char buf[2];

	int zero = 0;

	int one = 1;

	int rc;

	struct ctl_table ctl_entry = {

		.procname	= ctl->procname,

		.data		= &enabled,

		.maxlen		= sizeof(int),

		.extra1		= &zero,

		.extra2		= &one,

	};



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

	if (rc < 0 || !write)

		return rc;



	if (!*lenp || *ppos) {

		*lenp = 0;

		return 0;

	}

	if (!write) {

		memcpy(buf, topology_is_enabled() ? "1\n" : "0\n", ARRAY_SIZE(buf));

		len = strnlen(buf, ARRAY_SIZE(buf));

		if (len > *lenp)

			len = *lenp;

		if (copy_to_user(buffer, buf, len))

			return -EFAULT;

		goto out;

	}

	len = *lenp;

	if (copy_from_user(buf, buffer, len > sizeof(buf) ? sizeof(buf) : len))

		return -EFAULT;

	if (buf[0] != '0' && buf[0] != '1')

		return -EINVAL;

	mutex_lock(&smp_cpu_state_mutex);

	new_mode = topology_get_mode(buf[0] == '1');

	new_mode = topology_get_mode(enabled);

	if (topology_mode != new_mode) {

		topology_mode = new_mode;

		topology_schedule_update();

	}

	mutex_unlock(&smp_cpu_state_mutex);

	topology_flush_work();

out:

	*lenp = len;

	*ppos += len;

	return 0;



	return rc;

}



static struct ctl_table topology_ctl_table[] = {