Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754977Ab1DSUmw (ORCPT ); Tue, 19 Apr 2011 16:42:52 -0400 Received: from kroah.org ([198.145.64.141]:58993 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754297Ab1DSUmt (ORCPT ); Tue, 19 Apr 2011 16:42:49 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Tue Apr 19 13:41:19 2011 Message-Id: <20110419204119.055991318@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Tue, 19 Apr 2011 13:31:00 -0700 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, Alan Stern Subject: [22/28] USB: EHCI: unlink unused QHs when the controller is stopped In-Reply-To: <20110419204122.GA13268@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2875 Lines: 82 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Alan Stern commit 94ae4976e253757e9b03a44d27d41b20f1829d80 upstream. This patch (as1458) fixes a problem affecting ultra-reliable systems: When hardware failover of an EHCI controller occurs, the data structures do not get released correctly. This is because the routine responsible for removing unused QHs from the async schedule assumes the controller is running properly (the frame counter is used in determining how long the QH has been idle) -- but when a failover causes the controller to be electronically disconnected from the PCI bus, obviously it stops running. The solution is simple: Allow scan_async() to remove a QH from the async schedule if it has been idle for long enough _or_ if the controller is stopped. Signed-off-by: Alan Stern Reported-and-Tested-by: Dan Duval Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-q.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -1224,24 +1224,27 @@ static void start_unlink_async (struct e static void scan_async (struct ehci_hcd *ehci) { + bool stopped; struct ehci_qh *qh; enum ehci_timer_action action = TIMER_IO_WATCHDOG; ehci->stamp = ehci_readl(ehci, &ehci->regs->frame_index); timer_action_done (ehci, TIMER_ASYNC_SHRINK); rescan: + stopped = !HC_IS_RUNNING(ehci_to_hcd(ehci)->state); qh = ehci->async->qh_next.qh; if (likely (qh != NULL)) { do { /* clean any finished work for this qh */ - if (!list_empty (&qh->qtd_list) - && qh->stamp != ehci->stamp) { + if (!list_empty(&qh->qtd_list) && (stopped || + qh->stamp != ehci->stamp)) { int temp; /* unlinks could happen here; completion * reporting drops the lock. rescan using * the latest schedule, but don't rescan - * qhs we already finished (no looping). + * qhs we already finished (no looping) + * unless the controller is stopped. */ qh = qh_get (qh); qh->stamp = ehci->stamp; @@ -1262,9 +1265,9 @@ rescan: */ if (list_empty(&qh->qtd_list) && qh->qh_state == QH_STATE_LINKED) { - if (!ehci->reclaim - && ((ehci->stamp - qh->stamp) & 0x1fff) - >= (EHCI_SHRINK_FRAMES * 8)) + if (!ehci->reclaim && (stopped || + ((ehci->stamp - qh->stamp) & 0x1fff) + >= EHCI_SHRINK_FRAMES * 8)) start_unlink_async(ehci, qh); else action = TIMER_ASYNC_SHRINK; -- 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/