usb: gadget: udc-core: move sysfs_notify() to a workqueue

usb_gadget_set_state() will call sysfs_notify()
which might sleep. Some users might want to call
usb_gadget_set_state() from the very IRQ handler
which actually changes the gadget state.

Instead of having every UDC driver add their own
workqueue for such a simple notification, we're
adding it generically to our struct usb_gadget,
so the details are hidden from all UDC drivers.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/usb/gadget/udc-core.c b/drivers/usb/gadget/udc-core.c
index c28ac9872030..3122ab942f75 100644
--- a/drivers/usb/gadget/udc-core.c
+++ b/drivers/usb/gadget/udc-core.c
@@ -23,6 +23,7 @@
 #include <linux/list.h>
 #include <linux/err.h>
 #include <linux/dma-mapping.h>
+#include <linux/workqueue.h>
 
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
@@ -105,11 +106,18 @@ EXPORT_SYMBOL_GPL(usb_gadget_unmap_request);
 
 /* ------------------------------------------------------------------------- */
 
+static void usb_gadget_state_work(struct work_struct *work)
+{
+        struct usb_gadget       *gadget = work_to_gadget(work);
+
+        sysfs_notify(&gadget->dev.kobj, NULL, "status");
+}
+
 void usb_gadget_set_state(struct usb_gadget *gadget,
                 enum usb_device_state state)
 {
         gadget->state = state;
-        sysfs_notify(&gadget->dev.kobj, NULL, "status");
+        schedule_work(&gadget->work);
 }
 EXPORT_SYMBOL_GPL(usb_gadget_set_state);
 
@@ -196,6 +204,7 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
                 goto err1;
 
         dev_set_name(&gadget->dev, "gadget");
+        INIT_WORK(&gadget->work, usb_gadget_state_work);
         gadget->dev.parent = parent;
 
 #ifdef  CONFIG_HAS_DMA
@@ -315,6 +324,7 @@ found:
                 usb_gadget_remove_driver(udc);
 
         kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
+        flush_work(&gadget->work);
         device_unregister(&udc->dev);
         device_unregister(&gadget->dev);
 }