Suggested by scripts/coccinelle/api/memdup_user.cocci.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);
 
-       optval = kmalloc(cmd.optlen, GFP_KERNEL);
-       if (!optval) {
-               ret = -ENOMEM;
-               goto out1;
-       }
-
-       if (copy_from_user(optval, (void __user *) (unsigned long) cmd.optval,
-                          cmd.optlen)) {
-               ret = -EFAULT;
-               goto out2;
+       optval = memdup_user((void __user *) (unsigned long) cmd.optval,
+                            cmd.optlen);
+       if (IS_ERR(optval)) {
+               ret = PTR_ERR(optval);
+               goto out;
        }
 
        ret = ucma_set_option_level(ctx, cmd.level, cmd.optname, optval,
                                    cmd.optlen);
-out2:
        kfree(optval);
-out1:
+
+out:
        ucma_put_ctx(ctx);
        return ret;
 }