MFp4 //depot/projects/usb@160706

Resolve possible device side mode deadlock by creating another thread.

Submitted by:	Hans Petter Selasky

3 files changed, 25 insertions, 2 deletions

diff --git a/sys/dev/usb/controller/usb_controller.c b/sys/dev/usb/controller/usb_controller.c
index 474cbe5..cf30051 100644
--- a/sys/dev/usb/controller/usb_controller.c
+++ b/sys/dev/usb/controller/usb_controller.c
@@ -169,6 +169,10 @@ usb2_detach(device_t dev)
 
 	usb2_proc_free(&bus->explore_proc);
 
+	/* Get rid of control transfer process */
+
+	usb2_proc_free(&bus->control_xfer_proc);
+
 	return (0);
 }
 
@@ -412,6 +416,10 @@ usb2_attach_sub(device_t dev, struct usb2_bus *bus)
 	    &bus->bus_mtx, pname, USB_PRI_MED)) {
 		printf("WARNING: Creation of USB explore "
 		    "process failed.\n");
+	} else if (usb2_proc_create(&bus->control_xfer_proc,
+	    &bus->bus_mtx, pname, USB_PRI_MED)) {
+		printf("WARNING: Creation of USB control transfer "
+		    "process failed.\n");
 	} else {
 		/* Get final attach going */
 		USB_BUS_LOCK(bus);
diff --git a/sys/dev/usb/usb_bus.h b/sys/dev/usb/usb_bus.h
index 43cdf35..df3571f 100644
--- a/sys/dev/usb/usb_bus.h
+++ b/sys/dev/usb/usb_bus.h
@@ -62,7 +62,6 @@ struct usb2_sw_transfer {
 struct usb2_bus {
 	struct usb2_bus_stat stats_err;
 	struct usb2_bus_stat stats_ok;
-	struct usb2_process explore_proc;
 	struct usb2_sw_transfer roothub_req;
 	struct root_hold_token *bus_roothold;
 	/*
@@ -72,6 +71,13 @@ struct usb2_bus {
 	 */
 	struct usb2_process giant_callback_proc;
 	struct usb2_process non_giant_callback_proc;
+
+	/* Explore process */
+	struct usb2_process explore_proc;
+
+	/* Control request process */
+	struct usb2_process control_xfer_proc;
+
 	struct usb2_bus_msg explore_msg[2];
 	struct usb2_bus_msg detach_msg[2];
 	struct usb2_bus_msg attach_msg[2];
diff --git a/sys/dev/usb/usb_transfer.c b/sys/dev/usb/usb_transfer.c
index 41b07f1..bc44177 100644
--- a/sys/dev/usb/usb_transfer.c
+++ b/sys/dev/usb/usb_transfer.c
@@ -822,7 +822,16 @@ usb2_transfer_setup(struct usb2_device *udev,
 			info->done_m[1].hdr.pm_callback = &usb2_callback_proc;
 			info->done_m[1].xroot = info;
 
-			if (xfer_mtx == &Giant)
+			/* 
+			 * In device side mode control endpoint
+			 * requests need to run from a separate
+			 * context, else there is a chance of
+			 * deadlock!
+			 */
+			if (setup_start == usb2_control_ep_cfg)
+				info->done_p = 
+				    &udev->bus->control_xfer_proc;
+			else if (xfer_mtx == &Giant)
 				info->done_p = 
 				    &udev->bus->giant_callback_proc;
 			else