1 files changed, 15 insertions, 3 deletions

diff --git a/drivers/s390/char/tape_char.c b/drivers/s390/char/tape_char.c
index 2125ec7d95f0..539045acaad4 100644
--- a/drivers/s390/char/tape_char.c
+++ b/drivers/s390/char/tape_char.c
@@ -18,6 +18,7 @@
 #include <linux/proc_fs.h>
 #include <linux/mtio.h>
 #include <linux/smp_lock.h>
+#include <linux/compat.h>
 
 #include <asm/uaccess.h>
 
@@ -37,8 +38,9 @@ static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t
 static int tapechar_open(struct inode *,struct file *);
 static int tapechar_release(struct inode *,struct file *);
 static long tapechar_ioctl(struct file *, unsigned int, unsigned long);
-static long tapechar_compat_ioctl(struct file *, unsigned int,
-                          unsigned long);
+#ifdef CONFIG_COMPAT
+static long tapechar_compat_ioctl(struct file *, unsigned int, unsigned long);
+#endif
 
 static const struct file_operations tape_fops =
 {
@@ -46,7 +48,9 @@ static const struct file_operations tape_fops =
         .read = tapechar_read,
         .write = tapechar_write,
         .unlocked_ioctl = tapechar_ioctl,
+#ifdef CONFIG_COMPAT
         .compat_ioctl = tapechar_compat_ioctl,
+#endif
         .open = tapechar_open,
         .release = tapechar_release,
 };
@@ -457,15 +461,22 @@ tapechar_ioctl(struct file *filp, unsigned int no, unsigned long data)
         return rc;
 }
 
+#ifdef CONFIG_COMPAT
 static long
 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 {
         struct tape_device *device = filp->private_data;
         int rval = -ENOIOCTLCMD;
+        unsigned long argp;
 
+        /* The 'arg' argument of any ioctl function may only be used for
+         * pointers because of the compat pointer conversion.
+         * Consider this when adding new ioctls.
+         */
+        argp = (unsigned long) compat_ptr(data);
         if (device->discipline->ioctl_fn) {
                 mutex_lock(&device->mutex);
-                rval = device->discipline->ioctl_fn(device, no, data);
+                rval = device->discipline->ioctl_fn(device, no, argp);
                 mutex_unlock(&device->mutex);
                 if (rval == -EINVAL)
                         rval = -ENOIOCTLCMD;
@@ -473,6 +484,7 @@ tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 
         return rval;
 }
+#endif /* CONFIG_COMPAT */
 
 /*
  * Initialize character device frontend.