cdrom: don't open-code memdup_user()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index c206ccda899b..1b257ea9776a 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -3186,15 +3186,11 @@ static noinline int mmc_ioctl_dvd_read_struct(struct cdrom_device_info *cdi,
         if (!CDROM_CAN(CDC_DVD))
                 return -ENOSYS;
 
-        s = kmalloc(size, GFP_KERNEL);
-        if (!s)
-                return -ENOMEM;
+        s = memdup_user(arg, size);
+        if (IS_ERR(s))
+                return PTR_ERR(s);
 
         cd_dbg(CD_DO_IOCTL, "entering DVD_READ_STRUCT\n");
-        if (copy_from_user(s, arg, size)) {
-                kfree(s);
-                return -EFAULT;
-        }
 
         ret = dvd_read_struct(cdi, s, cgc);
         if (ret)