Module Name: src
Committed By: riastradh
Date: Thu Mar 3 05:48:23 UTC 2022
Modified Files:
src/sys/dev/usb: usbnet.c
Log Message:
usbnet: Fix ordering of actions in usbnet_stop.
Make sure all software activity is quiescent (callouts and tasks,
including ifmedia and mii callbacks -- anything that might trigger
register access) before asking the driver to stop the hardware. This
way, the driver uno_stop routine is guaranteed exclusive access to
the registers.
This will also enable us to simplify the callouts and tasks so they
don't have to check the software state -- to be done in a separate
commit.
To generate a diff of this commit:
cvs rdiff -u -r1.55 -r1.56 src/sys/dev/usb/usbnet.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/usb/usbnet.c
diff -u src/sys/dev/usb/usbnet.c:1.55 src/sys/dev/usb/usbnet.c:1.56
--- src/sys/dev/usb/usbnet.c:1.55 Thu Mar 3 05:48:14 2022
+++ src/sys/dev/usb/usbnet.c Thu Mar 3 05:48:22 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: usbnet.c,v 1.55 2022/03/03 05:48:14 riastradh Exp $ */
+/* $NetBSD: usbnet.c,v 1.56 2022/03/03 05:48:22 riastradh Exp $ */
/*
* Copyright (c) 2019 Matthew R. Green
@@ -31,7 +31,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.55 2022/03/03 05:48:14 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.56 2022/03/03 05:48:22 riastradh Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -1132,16 +1132,29 @@ usbnet_stop(struct usbnet *un, struct if
mutex_exit(&unp->unp_txlock);
mutex_exit(&unp->unp_rxlock);
+ /*
+ * Stop the timer first, then the task -- if the timer was
+ * already firing, we stop the task or wait for it complete
+ * only after if last fired. Setting unp_stopping prevents the
+ * timer task from being scheduled again.
+ */
+ callout_halt(&unp->unp_stat_ch, &unp->unp_core_lock);
+ usb_rem_task_wait(un->un_udev, &unp->unp_ticktask, USB_TASKQ_DRIVER,
+ &unp->unp_core_lock);
+
+ /*
+ * Now that the software is quiescent, ask the driver to stop
+ * the hardware. The driver's uno_stop routine now has
+ * exclusive access to any registers that might previously have
+ * been used by to ifmedia, mii, or ioctl callbacks.
+ */
uno_stop(un, ifp, disable);
+ /* Clear the watchdog timer. */
mutex_enter(&unp->unp_txlock);
unp->unp_timer = 0;
mutex_exit(&unp->unp_txlock);
- callout_halt(&unp->unp_stat_ch, &unp->unp_core_lock);
- usb_rem_task_wait(un->un_udev, &unp->unp_ticktask, USB_TASKQ_DRIVER,
- &unp->unp_core_lock);
-
/* Stop transfers. */
usbnet_ep_stop_pipes(un);
