clocksource: Split out user string input
Split out the user string input for clocksource override. Preparatory
patch for unbind.
[ jstultz: Fix an off by one error ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130425143435.895851338@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 9782997..d7f1a45 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -174,7 +174,8 @@
static struct clocksource *curr_clocksource;
static LIST_HEAD(clocksource_list);
static DEFINE_MUTEX(clocksource_mutex);
-static char override_name[32];
+#define CS_NAME_LEN 32
+static char override_name[CS_NAME_LEN];
static int finished_booting;
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
@@ -838,6 +839,23 @@
return count;
}
+static size_t clocksource_get_uname(const char *buf, char *dst, size_t cnt)
+{
+ size_t ret = cnt;
+
+ /* strings from sysfs write are not 0 terminated! */
+ if (!cnt || cnt >= CS_NAME_LEN)
+ return -EINVAL;
+
+ /* strip of \n: */
+ if (buf[cnt-1] == '\n')
+ cnt--;
+ if (cnt > 0)
+ memcpy(dst, buf, cnt);
+ dst[cnt] = 0;
+ return ret;
+}
+
/**
* sysfs_override_clocksource - interface for manually overriding clocksource
* @dev: unused
@@ -852,22 +870,13 @@
struct device_attribute *attr,
const char *buf, size_t count)
{
- size_t ret = count;
-
- /* strings from sysfs write are not 0 terminated! */
- if (count >= sizeof(override_name))
- return -EINVAL;
-
- /* strip of \n: */
- if (buf[count-1] == '\n')
- count--;
+ size_t ret;
mutex_lock(&clocksource_mutex);
- if (count > 0)
- memcpy(override_name, buf, count);
- override_name[count] = 0;
- clocksource_select();
+ ret = clocksource_get_uname(buf, override_name, count);
+ if (ret >= 0)
+ clocksource_select();
mutex_unlock(&clocksource_mutex);