usb: gadget: f_hid: actually limit the number of instances

There is a predefined maximum number of hid instances, currently 4.
A chrdev region is allocated accordingly, but with configfs the user
can create as many hid function directories as they like. To make
the number of hid instances consistent with the number of allocated minors,
the limit is enforced at directory creation time.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index f7f35a36c09a06eab17ef2e5af013ee3de2b5b8e..6df9715a4bcd31179cb190100df45b2dd975a0d2 100644 (file)
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -699,6 +699,10 @@ static inline int hidg_get_minor(void)
        int ret;
 
        ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
+       if (ret >= HIDG_MINORS) {
+               ida_simple_remove(&hidg_ida, ret);
+               ret = -ENODEV;
+       }
 
        return ret;
 }