Serialise USB re-enumeration with the USB explore thread.

This patch can solve problems when multiple USB devices are
re-enumerated at the same time on the same bus.

Approved by:    thompsa (mentor)

1 files changed, 36 insertions, 13 deletions

diff --git a/sys/dev/usb/usb_dev.c b/sys/dev/usb/usb_dev.c
index cb23fcd..5ccbae6 100644
--- a/sys/dev/usb/usb_dev.c
+++ b/sys/dev/usb/usb_dev.c
@@ -964,7 +964,6 @@ usb_dev_uninit(void *arg)
 	if (usb_dev != NULL) {
 		destroy_dev(usb_dev);
 		usb_dev = NULL;
-	
 	}
 	mtx_destroy(&usb_ref_lock);
 	sx_destroy(&usb_sym_lock);
@@ -1058,21 +1057,45 @@ usb_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int fflag, struct thread*
 		err = usb_ioctl_f_sub(f, cmd, addr, td);
 	}
 	KASSERT(f != NULL, ("fifo not found"));
-	if (err == ENOIOCTL) {
-		err = (f->methods->f_ioctl) (f, cmd, addr, fflags);
-		DPRINTFN(2, "f_ioctl cmd 0x%lx = %d\n", cmd, err);
-		if (err == ENOIOCTL) {
-			if (usb_usb_ref_device(cpd, &refs)) {
-				err = ENXIO;
-				goto done;
-			}
-			err = (f->methods->f_ioctl_post) (f, cmd, addr, fflags);
-			DPRINTFN(2, "f_ioctl_post cmd 0x%lx = %d\n", cmd, err);
-		}
+	if (err != ENOIOCTL)
+		goto done;
+
+	err = (f->methods->f_ioctl) (f, cmd, addr, fflags);
+
+	DPRINTFN(2, "f_ioctl cmd 0x%lx = %d\n", cmd, err);
+
+	if (err != ENOIOCTL)
+		goto done;
+
+	if (usb_usb_ref_device(cpd, &refs)) {
+		err = ENXIO;
+		goto done;
 	}
-	if (err == ENOIOCTL) {
+
+	err = (f->methods->f_ioctl_post) (f, cmd, addr, fflags);
+
+	DPRINTFN(2, "f_ioctl_post cmd 0x%lx = %d\n", cmd, err);
+
+	if (err == ENOIOCTL)
 		err = ENOTTY;
+
+	if (err)
+		goto done;
+
+	/* Wait for re-enumeration, if any */
+
+	while (f->udev->re_enumerate_wait != 0) {
+
+		usb_unref_device(cpd, &refs);
+
+		usb_pause_mtx(NULL, hz / 128);
+
+		if (usb_ref_device(cpd, &refs, 1 /* need uref */)) {
+			err = ENXIO;
+			goto done;
+		}
 	}
+
 done:
 	usb_unref_device(cpd, &refs);
 	return (err);