From 8236800da115a3e24b9165c573067343f51cf5ea Mon Sep 17 00:00:00 2001 From: Krzysztof Opasiak Date: Mon, 16 Jan 2017 08:40:57 +0100 Subject: [PATCH] usb: gadget: udc-core: Rescan pending list on driver unbind Since: commit 855ed04a3758 ("usb: gadget: udc-core: independent registration of gadgets and gadget drivers") if we load gadget module but there is no free udc available then it will be stored on a pending gadgets list. $ modprobe g_zero.ko $ modprobe g_ether.ko [] udc-core: couldn't find an available UDC - added [g_ether] to list of pending drivers We scan this list each time when new UDC appears in system. But we can get a free UDC each time after gadget unbind. This commit add scanning of that list directly after unbinding gadget from udc. Thanks to this, when we unload first gadget: $ rmmod g_zero.ko gadget which is pending is automatically attached to that UDC (if name matches). Fixes: 855ed04a3758 ("usb: gadget: udc-core: independent registration of gadgets and gadget drivers") Cc: stable Signed-off-by: Krzysztof Opasiak Signed-off-by: Felipe Balbi --- drivers/usb/gadget/udc/core.c | 45 ++++++++++++++++++++++++----------- 1 file changed, 31 insertions(+), 14 deletions(-) diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 0402177f93cd..d685d82dcf48 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -1080,6 +1080,24 @@ static void usb_udc_nop_release(struct device *dev) dev_vdbg(dev, "%s\n", __func__); } +/* should be called with udc_lock held */ +static int check_pending_gadget_drivers(struct usb_udc *udc) +{ + struct usb_gadget_driver *driver; + int ret = 0; + + list_for_each_entry(driver, &gadget_driver_pending_list, pending) + if (!driver->udc_name || strcmp(driver->udc_name, + dev_name(&udc->dev)) == 0) { + ret = udc_bind_to_driver(udc, driver); + if (ret != -EPROBE_DEFER) + list_del(&driver->pending); + break; + } + + return ret; +} + /** * usb_add_gadget_udc_release - adds a new gadget to the udc class driver list * @parent: the parent device to this udc. Usually the controller driver's @@ -1093,7 +1111,6 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget, void (*release)(struct device *dev)) { struct usb_udc *udc; - struct usb_gadget_driver *driver; int ret = -ENOMEM; udc = kzalloc(sizeof(*udc), GFP_KERNEL); @@ -1136,17 +1153,9 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget, udc->vbus = true; /* pick up one of pending gadget drivers */ - list_for_each_entry(driver, &gadget_driver_pending_list, pending) { - if (!driver->udc_name || strcmp(driver->udc_name, - dev_name(&udc->dev)) == 0) { - ret = udc_bind_to_driver(udc, driver); - if (ret != -EPROBE_DEFER) - list_del(&driver->pending); - if (ret) - goto err5; - break; - } - } + ret = check_pending_gadget_drivers(udc); + if (ret) + goto err5; mutex_unlock(&udc_lock); @@ -1356,14 +1365,22 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver) return -EINVAL; mutex_lock(&udc_lock); - list_for_each_entry(udc, &udc_list, list) + list_for_each_entry(udc, &udc_list, list) { if (udc->driver == driver) { usb_gadget_remove_driver(udc); usb_gadget_set_state(udc->gadget, - USB_STATE_NOTATTACHED); + USB_STATE_NOTATTACHED); + + /* Maybe there is someone waiting for this UDC? */ + check_pending_gadget_drivers(udc); + /* + * For now we ignore bind errors as probably it's + * not a valid reason to fail other's gadget unbind + */ ret = 0; break; } + } if (ret) { list_del(&driver->pending); -- 2.20.1