From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4CECC433DB for ; Mon, 21 Dec 2020 18:05:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9281E22C9C for ; Mon, 21 Dec 2020 18:05:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726374AbgLUSFV (ORCPT ); Mon, 21 Dec 2020 13:05:21 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:35974 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725902AbgLUSFU (ORCPT ); Mon, 21 Dec 2020 13:05:20 -0500 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1krPXt-00DBHi-F6; Mon, 21 Dec 2020 19:04:33 +0100 Date: Mon, 21 Dec 2020 19:04:33 +0100 From: Andrew Lunn To: Masahiro Yamada , Hauke Mehrtens Cc: "David S . Miller" , Jakub Kicinski , Networking , Linux Kernel Mailing List , Miguel Ojeda , Arnd Bergmann , Heiner Kallweit Subject: Re: [PATCH] net: lantiq_etop: check the result of request_irq() Message-ID: <20201221180433.GE3107610@lunn.ch> References: <20201221054323.247483-1-masahiroy@kernel.org> <20201221152645.GH3026679@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Dec 22, 2020 at 12:59:08AM +0900, Masahiro Yamada wrote: > On Tue, Dec 22, 2020 at 12:26 AM Andrew Lunn wrote: > > > > On Mon, Dec 21, 2020 at 02:43:23PM +0900, Masahiro Yamada wrote: > > > The declaration of request_irq() in is marked as > > > __must_check. > > > > > > Without the return value check, I see the following warnings: > > > > > > drivers/net/ethernet/lantiq_etop.c: In function 'ltq_etop_hw_init': > > > drivers/net/ethernet/lantiq_etop.c:273:4: warning: ignoring return value of 'request_irq', declared with attribute warn_unused_result [-Wunused-result] > > > 273 | request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx", priv); > > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > drivers/net/ethernet/lantiq_etop.c:281:4: warning: ignoring return value of 'request_irq', declared with attribute warn_unused_result [-Wunused-result] > > > 281 | request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv); > > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > > > Reported-by: Miguel Ojeda > > > Signed-off-by: Masahiro Yamada > > > --- > > > > > > drivers/net/ethernet/lantiq_etop.c | 13 +++++++++++-- > > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/lantiq_etop.c b/drivers/net/ethernet/lantiq_etop.c > > > index 2d0c52f7106b..960494f9752b 100644 > > > --- a/drivers/net/ethernet/lantiq_etop.c > > > +++ b/drivers/net/ethernet/lantiq_etop.c > > > @@ -264,13 +264,18 @@ ltq_etop_hw_init(struct net_device *dev) > > > for (i = 0; i < MAX_DMA_CHAN; i++) { > > > int irq = LTQ_DMA_CH0_INT + i; > > > struct ltq_etop_chan *ch = &priv->ch[i]; > > > + int ret; > > > > > > ch->idx = ch->dma.nr = i; > > > ch->dma.dev = &priv->pdev->dev; > > > > > > if (IS_TX(i)) { > > > ltq_dma_alloc_tx(&ch->dma); > > > - request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx", priv); > > > + ret = request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx", priv); > > > + if (ret) { > > > + netdev_err(dev, "failed to request irq\n"); > > > + return ret; > > > > You need to cleanup what ltq_dma_alloc_tx() did. > > > Any failure from this function will roll back > in the following paths: > > ltq_etop_hw_exit() > -> ltq_etop_free_channel() > -> ltq_dma_free() > > > So, dma is freed anyway. > > One problem I see is, > ltq_etop_hw_exit() frees all DMA channels, > some of which may not have been allocated yet. > > If it is a bug, it is an existing bug. > > > > > > > + } > > > } else if (IS_RX(i)) { > > > ltq_dma_alloc_rx(&ch->dma); > > > for (ch->dma.desc = 0; ch->dma.desc < LTQ_DESC_NUM; > > > @@ -278,7 +283,11 @@ ltq_etop_hw_init(struct net_device *dev) > > > if (ltq_etop_alloc_skb(ch)) > > > return -ENOMEM; > > > This -ENOMEM does not roll back anything here. > > As stated above, dma_free_coherent() is called. > The problem is, ltq_etop_hw_exit() rolls back too much. > > If your requirement is "this driver is completely wrong. Please rewrite it", > sorry, I cannot (unless I am paid to do so). > > I am just following this driver's roll-back model. > > Please do not expect more to a person who > volunteers to eliminate build warnings. > > Of course, if somebody volunteers to rewrite this driver correctly, > that is appreciated. Hi Hauke Do you still have this hardware? Do you have time to take a look at the cleanup code? Thanks Andrew