[PATCH v2] misc: mic: Use memdup_user() as a cleanup

[Vasyl Gomonovych]

Fix coccicheck warning which recommends to use memdup_user():

drivers/misc/mic/vop/vop_vringh.c:940:14-21: WARNING opportunity for memdup_user
drivers/misc/mic/vop/vop_vringh.c:998:8-15: WARNING opportunity for memdup_user

Generated by: scripts/coccinelle/memdup_user/memdup_user.cocci

Changelog:
 - v1:
   - Replace kzalloc + copy_from_user on memdup_user
 - v2:
   - Clear forgotten done label
     After merging the char-misc tree, today's linux-next build
     (x86_64_allmodconfig) produced this warning:
     drivers/misc/mic/vop/vop_vringh.c: In function 'vop_ioctl':
     drivers/misc/mic/vop/vop_vringh.c:1001:1: warning: label 'done' defined 
but not used [-Wunused-label]

Signed-off-by: Vasyl Gomonovych <gomonov...@gmail.com>
---
 drivers/misc/mic/vop/vop_vringh.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/drivers/misc/mic/vop/vop_vringh.c 
b/drivers/misc/mic/vop/vop_vringh.c
index fed992e..27db64e 100644
--- a/drivers/misc/mic/vop/vop_vringh.c
+++ b/drivers/misc/mic/vop/vop_vringh.c
@@ -937,13 +937,10 @@ static long vop_ioctl(struct file *f, unsigned int cmd, 
unsigned long arg)
                    dd.num_vq > MIC_MAX_VRINGS)
                        return -EINVAL;
 
-               dd_config = kzalloc(mic_desc_size(&dd), GFP_KERNEL);
-               if (!dd_config)
-                       return -ENOMEM;
-               if (copy_from_user(dd_config, argp, mic_desc_size(&dd))) {
-                       ret = -EFAULT;
-                       goto free_ret;
-               }
+               dd_config = memdup_user(argp, mic_desc_size(&dd));
+               if (IS_ERR(dd_config))
+                       return PTR_ERR(dd_config);
+
                /* Ensure desc has not changed between the two reads */
                if (memcmp(&dd, dd_config, sizeof(dd))) {
                        ret = -EINVAL;
@@ -995,17 +992,12 @@ static long vop_ioctl(struct file *f, unsigned int cmd, 
unsigned long arg)
                ret = vop_vdev_inited(vdev);
                if (ret)
                        goto __unlock_ret;
-               buf = kzalloc(vdev->dd->config_len, GFP_KERNEL);
-               if (!buf) {
-                       ret = -ENOMEM;
+               buf = memdup_user(argp, vdev->dd->config_len);
+               if (IS_ERR(buf)) {
+                       ret = PTR_ERR(buf);
                        goto __unlock_ret;
                }
-               if (copy_from_user(buf, argp, vdev->dd->config_len)) {
-                       ret = -EFAULT;
-                       goto done;
-               }
                ret = vop_virtio_config_change(vdev, buf);
-done:
                kfree(buf);
 __unlock_ret:
                mutex_unlock(&vdev->vdev_mutex);
-- 
1.9.1