[PATCH v2] usb: cdc-wdm: use memdup_user

[Geliang Tang]

Use memdup_user() helper instead of open-coding to simplify the code.

Signed-off-by: Geliang Tang <geliangt...@gmail.com>
---
Changes in v2:
 - return count instead of "rv < 0 ? rv : count".
---
 drivers/usb/class/cdc-wdm.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 08669fe..8f97224 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -361,17 +361,9 @@ static ssize_t wdm_write
        if (we < 0)
                return usb_translate_errors(we);
 
-       buf = kmalloc(count, GFP_KERNEL);
-       if (!buf) {
-               rv = -ENOMEM;
-               goto outnl;
-       }
-
-       r = copy_from_user(buf, buffer, count);
-       if (r > 0) {
-               rv = -EFAULT;
-               goto out_free_mem;
-       }
+       buf = memdup_user(buffer, count);
+       if (IS_ERR(buf))
+               return PTR_ERR(buf);
 
        /* concurrent writes and disconnect */
        r = mutex_lock_interruptible(&desc->wlock);
@@ -441,8 +433,7 @@ static ssize_t wdm_write
 
        usb_autopm_put_interface(desc->intf);
        mutex_unlock(&desc->wlock);
-outnl:
-       return rv < 0 ? rv : count;
+       return count;
 
 out_free_mem_pm:
        usb_autopm_put_interface(desc->intf);
-- 
2.9.3