From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756962Ab0ITS6m (ORCPT ); Mon, 20 Sep 2010 14:58:42 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:65237 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753262Ab0ITS6l convert rfc822-to-8bit (ORCPT ); Mon, 20 Sep 2010 14:58:41 -0400 Date: Mon, 20 Sep 2010 21:00:35 +0200 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH] usb: gadget: rndis: don't use dev_get_stats() In-reply-to: <1285008527.2323.52.camel@edumazet-laptop> To: David Miller , Eric Dumazet Cc: dbrownell@users.sourceforge.net, gregkh@suse.de, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Message-id: Organization: Samsung Electronics MIME-version: 1.0 Content-type: text/plain; charset=utf-8; format=flowed; delsp=yes Content-transfer-encoding: 8BIT User-Agent: Opera Mail/10.62 (Linux) References: <20100920.112727.214208208.davem@davemloft.net> <1285008527.2323.52.camel@edumazet-laptop> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> From: Michal Nazarewicz >>> This commit removes the call to dev_get_stats() from the >>> gen_ndis_query_resp() function. Since spin_lock_bh() was >>> added to dev_txq_stats_fold() the call started causing >>> warnings. This is because gen_ndis_query_resp() can be >>> (indirectly) called from rndis_command_complete() which is >>> called with interrupts disabled. > Le lundi 20 septembre 2010 à 11:27 -0700, David Miller a écrit : >> The way this works is dev_get_stats() takes that "temp" object the >> caller provides, it writes the correct statistics into it (with any >> necessary translations), and then passes back a pointer to it. [...] >> Like I originally suggested, you need to rearrange the code in this >> driver such that the gen_ndis_query_resp() work happens in a tasklet, >> workqueue, or some other non-hardware-irq context. On Mon, 20 Sep 2010 20:48:47 +0200, Eric Dumazet wrote: > Hmm, maybe its a bit difficult to fix this problem for stable kernel. > > What we could do is assume rndis wont use a device driver that actually > needs txq tx stats folding, and just use following interim patch ? > > diff --git a/net/core/dev.c b/net/core/dev.c > index b9b22a3..31d5424 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -5288,6 +5288,14 @@ void dev_txq_stats_fold(const struct net_device *dev, > unsigned int i; > struct netdev_queue *txq; >+ /* temporary hack : rndis calls us under hard irq */ > + if (WARN_ON_ONCE(in_irq())) { > + stats->tx_bytes = dev->stats.tx_bytes; > + stats->tx_packets = dev->stats.tx_packets; > + stats->tx_dropped = dev->stats.tx_dropped; > + return; > + } > + > for (i = 0; i < dev->num_tx_queues; i++) { > txq = netdev_get_tx_queue(dev, i); > spin_lock_bh(&txq->_xmit_lock); I think it's better to put such temporary fix inside RNDIS code. It seems there is no need to clutter the whole subsystem with temporary fix. -- Best regards, _ _ | Humble Liege of Serenely Enlightened Majesty of o' \,=./ `o | Computer Science, Michał "mina86" Nazarewicz (o o) +----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo--