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authorriastradh <riastradh@NetBSD.org>2022-03-13 11:29:01 +0000
committerriastradh <riastradh@NetBSD.org>2022-03-13 11:29:01 +0000
commit92feef340d80674016bccb6a127f8100b74acea1 (patch)
tree44f2c09403ff72d5c40a2126ba561976456b2368 /sys/dev
parentfd6bcfb67366b341462d5ceaa82b8f85796573a5 (diff)
usb: Clarify contract of usbd_xfer_trycomplete.
No functional change. This rule has always been in place since usbd_xfer_trycomplete was created, just wasn't clearly articulated anywhere.
Diffstat (limited to 'sys/dev')
-rw-r--r--sys/dev/usb/usbdi.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/sys/dev/usb/usbdi.c b/sys/dev/usb/usbdi.c
index 9583d1ef08c..d2054e2e96e 100644
--- a/sys/dev/usb/usbdi.c
+++ b/sys/dev/usb/usbdi.c
@@ -1,4 +1,4 @@
-/* $NetBSD: usbdi.c,v 1.235 2022/03/13 11:28:42 riastradh Exp $ */
+/* $NetBSD: usbdi.c,v 1.236 2022/03/13 11:29:01 riastradh Exp $ */
/*
* Copyright (c) 1998, 2012, 2015 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: usbdi.c,v 1.235 2022/03/13 11:28:42 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: usbdi.c,v 1.236 2022/03/13 11:29:01 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_usb.h"
@@ -1506,7 +1506,11 @@ usbd_get_string0(struct usbd_device *dev, int si, char *buf, int unicode)
* in a host controller interrupt handler.
*
* Caller must either hold the bus lock or have the bus in polling
- * mode.
+ * mode. If this succeeds, caller must proceed to call
+ * usb_complete_transfer under the bus lock or with polling
+ * enabled -- must not release and reacquire the bus lock in the
+ * meantime. Failing to heed this rule may lead to catastrophe
+ * with abort or timeout.
*/
bool
usbd_xfer_trycomplete(struct usbd_xfer *xfer)