[PATCH] usb: musb: Fix runtime PM imbalance on error

[Dinghao Liu]

When copy_from_user() returns an error code, a pairing
runtime PM usage counter decrement is needed to keep
the counter balanced.

Signed-off-by: Dinghao Liu <dinghao....@zju.edu.cn>
---
 drivers/usb/musb/musb_debugfs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_debugfs.c b/drivers/usb/musb/musb_debugfs.c
index 7b6281ab62ed..837c38a5e4ef 100644
--- a/drivers/usb/musb/musb_debugfs.c
+++ b/drivers/usb/musb/musb_debugfs.c
@@ -178,8 +178,11 @@ static ssize_t musb_test_mode_write(struct file *file,
 
        memset(buf, 0x00, sizeof(buf));
 
-       if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+       if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) {
+               pm_runtime_mark_last_busy(musb->controller);
+               pm_runtime_put_autosuspend(musb->controller);
                return -EFAULT;
+       }
 
        if (strstarts(buf, "force host full-speed"))
                test = MUSB_TEST_FORCE_HOST | MUSB_TEST_FORCE_FS;
-- 
2.17.1