From mboxrd@z Thu Jan 1 00:00:00 1970 From: linas@austin.ibm.com (Linas Vepstas) Subject: [PATCH 4/5]: spidernet: transmit race Date: Fri, 9 Feb 2007 18:22:05 -0600 Message-ID: <20070210002205.GD2396@austin.ibm.com> References: <20070210000128.GJ5616@austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linuxppc-dev@ozlabs.org, netdev@vger.kernel.org, James K Lewis , Jens Osterkamp , Kou Ishizaki To: jgarzik@pobox.com Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:36631 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423376AbXBJAWI (ORCPT ); Fri, 9 Feb 2007 19:22:08 -0500 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e2.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l1A0M6Mq015114 for ; Fri, 9 Feb 2007 19:22:06 -0500 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v8.2) with ESMTP id l1A0M6RQ300334 for ; Fri, 9 Feb 2007 19:22:06 -0500 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l1A0M5xu023898 for ; Fri, 9 Feb 2007 19:22:06 -0500 Content-Disposition: inline In-Reply-To: <20070210000128.GJ5616@austin.ibm.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Multiple threads performing a transmit can race into the spidernet tx ring cleanup code. This puts the relevant check under a lock. Signed-off-by: Linas Vepstas Cc: James K Lewis Cc: Jens Osterkamp Cc: Kou Ishizaki ---- drivers/net/spider_net.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) Index: linux-2.6.20-git4/drivers/net/spider_net.c =================================================================== --- linux-2.6.20-git4.orig/drivers/net/spider_net.c 2007-02-09 17:30:13.000000000 -0600 +++ linux-2.6.20-git4/drivers/net/spider_net.c 2007-02-09 17:37:41.000000000 -0600 @@ -767,8 +767,12 @@ spider_net_release_tx_chain(struct spide unsigned long flags; int status; - while (chain->tail != chain->head) { + while (1) { spin_lock_irqsave(&chain->lock, flags); + if (chain->tail == chain->head) { + spin_unlock_irqrestore(&chain->lock, flags); + return 0; + } descr = chain->tail; hwdescr = descr->hwdescr;