usb: musb: Fix runtime PM imbalance on error

commit e4befc121df03dc8ed2ac1031c98f9538e244bae upstream.

When copy_from_user() returns an error code, there
is a runtime PM usage counter imbalance.

Fix this by moving copy_from_user() to the beginning
of this function.

Fixes: 7b6c1b4c0e1e ("usb: musb: fix runtime PM in debugfs")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200525025049.3400-7-b-liu@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/musb/musb_debugfs.c b/drivers/usb/musb/musb_debugfs.c
index 952733ceaac8d47bfc544adb1fa8c787609d7790..480b2119f1e7d7debfa128d1ee1d8fe7aaf9a3eb 100644 (file)
--- a/drivers/usb/musb/musb_debugfs.c
+++ b/drivers/usb/musb/musb_debugfs.c
@@ -206,6 +206,11 @@ static ssize_t musb_test_mode_write(struct file *file,
        u8                      test;
        char                    buf[24];
 
+       memset(buf, 0x00, sizeof(buf));
+
+       if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+               return -EFAULT;
+
        pm_runtime_get_sync(musb->controller);
        test = musb_readb(musb->mregs, MUSB_TESTMODE);
        if (test) {
@@ -214,11 +219,6 @@ static ssize_t musb_test_mode_write(struct file *file,
                goto ret;
        }
 
-       memset(buf, 0x00, sizeof(buf));
-
-       if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
-               return -EFAULT;
-
        if (strstarts(buf, "force host full-speed"))
                test = MUSB_TEST_FORCE_HOST | MUSB_TEST_FORCE_FS;