From mboxrd@z Thu Jan 1 00:00:00 1970 From: linas@austin.ibm.com (Linas Vepstas) Subject: [PATCH 3/15] spidernet: Don't terminate the RX ring Date: Mon, 11 Jun 2007 13:23:42 -0500 Message-ID: <20070611182342.GC13741@austin.ibm.com> References: <20070607191707.GA7904@austin.ibm.com> <1181265151.6026.1.camel@concordia.ozlabs.ibm.com> <20070608170608.GI7904@austin.ibm.com> <20070608172020.GA31089@havoc.gtf.org> <20070611181429.GA4397@austin.ibm.com> <20070611181702.GA13741@austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Michael Ellerman , netdev@vger.kernel.org, cbe-oss-dev@ozlabs.org To: Jeff Garzik Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:41933 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752969AbXFKSXo (ORCPT ); Mon, 11 Jun 2007 14:23:44 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e6.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l5BIOnI3025381 for ; Mon, 11 Jun 2007 14:24:49 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.3) with ESMTP id l5BINhUa559446 for ; Mon, 11 Jun 2007 14:23:43 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l5BINgkR018196 for ; Mon, 11 Jun 2007 14:23:43 -0400 Content-Disposition: inline In-Reply-To: <20070611181702.GA13741@austin.ibm.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org The terminated RX ring will cause trouble during the RX ram full conditions, leading to a hung driver, as the hardware can't find the next descr. There is no real reason to terminate the RX ring; it doesn't make the operation any smooother, and it does require an extra sync. So don't do it. Signed-off-by: Linas Vepstas ---- drivers/net/spider_net.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) Index: linux-2.6.22-rc1/drivers/net/spider_net.c =================================================================== --- linux-2.6.22-rc1.orig/drivers/net/spider_net.c 2007-06-08 17:35:33.000000000 -0500 +++ linux-2.6.22-rc1/drivers/net/spider_net.c 2007-06-08 17:36:19.000000000 -0500 @@ -460,13 +460,9 @@ spider_net_prepare_rx_descr(struct spide hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE; } else { hwdescr->buf_addr = buf; - hwdescr->next_descr_addr = 0; wmb(); hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_CARDOWNED | SPIDER_NET_DMAC_NOINTR_COMPLETE; - - wmb(); - descr->prev->hwdescr->next_descr_addr = descr->bus_addr; } return 0; @@ -541,12 +537,16 @@ spider_net_refill_rx_chain(struct spider static int spider_net_alloc_rx_skbs(struct spider_net_card *card) { - int result; - struct spider_net_descr_chain *chain; + struct spider_net_descr_chain *chain = &card->rx_chain; + struct spider_net_descr *start = chain->tail; + struct spider_net_descr *descr = start; - result = -ENOMEM; + /* Link up the hardware chain pointers */ + do { + descr->prev->hwdescr->next_descr_addr = descr->bus_addr; + descr = descr->next; + } while (descr != start); - chain = &card->rx_chain; /* Put at least one buffer into the chain. if this fails, * we've got a problem. If not, spider_net_refill_rx_chain * will do the rest at the end of this function. */ @@ -563,7 +563,7 @@ spider_net_alloc_rx_skbs(struct spider_n error: spider_net_free_rx_chain_contents(card); - return result; + return -ENOMEM; } /**