[S390] sclp_async: Use kstrtoul_from_user

This patch replaces the code for getting an unsigned long from a
userspace buffer by a simple call to kstroul_from_user.
This makes it easier to read and less error prone.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c
index 7ad30e72f868..5f9f929e891c 100644
--- a/drivers/s390/char/sclp_async.c
+++ b/drivers/s390/char/sclp_async.c
@@ -82,12 +82,9 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write,
                         return -EFAULT;
         } else {
                 len = *count;
-                rc = copy_from_user(buf, buffer, sizeof(buf));
-                if (rc != 0)
-                        return -EFAULT;
-                buf[sizeof(buf) - 1] = '\0';
-                if (strict_strtoul(buf, 0, &val) != 0)
-                        return -EINVAL;
+                rc = kstrtoul_from_user(buffer, len, 0, &val);
+                if (rc)
+                        return rc;
                 if (val != 0 && val != 1)
                         return -EINVAL;
                 callhome_enabled = val;