Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752936Ab0KSWEL (ORCPT ); Fri, 19 Nov 2010 17:04:11 -0500 Received: from kroah.org ([198.145.64.141]:52796 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757863Ab0KSWEB (ORCPT ); Fri, 19 Nov 2010 17:04:01 -0500 X-Mailbox-Line: From gregkh@clark.site Fri Nov 19 14:01:22 2010 Message-Id: <20101119220122.360480409@clark.site> User-Agent: quilt/0.48-11.2 Date: Fri, 19 Nov 2010 14:00:33 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Max Vozeler Subject: [02/66] staging: usbip: Process event flags without delay In-Reply-To: <20101119220309.GA15562@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2737 Lines: 103 2.6.36-stable review patch. If anyone has any objections, please let us know. ------------------ From: Max Vozeler commit 584c5b7cf06194464240280483ee0376cdddbbae upstream. The way the event handler works can cause it to delay events until eventual wakeup for another event. For example, on device detach (vhci): - Write to sysfs detach file -> usbip_event_add(VDEV_EVENT_DOWN) -> wakeup() #define VDEV_EVENT_DOWN (USBIP_EH_SHUTDOWN | USBIP_EH_RESET). - Event thread wakes up and passes the event to event_handler() to process. - It processes and clears the USBIP_EH_SHUTDOWN flag then returns. - The outer event loop (event_handler_loop()) calls wait_event_interruptible(). The processing of the second flag which is part of VDEV_EVENT_DOWN (USBIP_EH_RESET) did not happen yet. It is delayed until the next event. This means the ->reset callback may not happen for a long time (if ever), leaving the usbip port in a weird state which prevents its reuse. This patch changes the handler to process all flags before waiting for another wakeup. I have verified this change to fix a problem which prevented reattach of a usbip device. It also helps for socket errors which missed the RESET as well. The delayed event processing also affects the stub side of usbip and the error handling there. Signed-off-by: Max Vozeler Reported-by: Marco Lancione Tested-by: Luc Jalbert Signed-off-by: Greg Kroah-Hartman --- drivers/staging/usbip/usbip_event.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-) --- a/drivers/staging/usbip/usbip_event.c +++ b/drivers/staging/usbip/usbip_event.c @@ -38,21 +38,13 @@ static int event_handler(struct usbip_de ud->eh_ops.shutdown(ud); ud->event &= ~USBIP_EH_SHUTDOWN; - - break; } - /* Stop the error handler. */ - if (ud->event & USBIP_EH_BYE) - return -1; - /* Reset the device. */ if (ud->event & USBIP_EH_RESET) { ud->eh_ops.reset(ud); ud->event &= ~USBIP_EH_RESET; - - break; } /* Mark the device as unusable. */ @@ -60,13 +52,11 @@ static int event_handler(struct usbip_de ud->eh_ops.unusable(ud); ud->event &= ~USBIP_EH_UNUSABLE; - - break; } - /* NOTREACHED */ - printk(KERN_ERR "%s: unknown event\n", __func__); - return -1; + /* Stop the error handler. */ + if (ud->event & USBIP_EH_BYE) + return -1; } return 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/