Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752777Ab0FPI1t (ORCPT ); Wed, 16 Jun 2010 04:27:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43780 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751641Ab0FPI1f (ORCPT ); Wed, 16 Jun 2010 04:27:35 -0400 Date: Wed, 16 Jun 2010 11:22:40 +0300 From: "Michael S. Tsirkin" To: Hidetoshi Seto Cc: Rusty Russell , Jesse Barnes , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] pci: fix compilation when CONFIG_PCI_MSI=n Message-ID: <20100616082240.GA3848@redhat.com> References: <201006161421.11148.rusty@rustcorp.com.au> <4C186A87.6040005@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4C186A87.6040005@jp.fujitsu.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3349 Lines: 95 On Wed, Jun 16, 2010 at 03:09:11PM +0900, Hidetoshi Seto wrote: > (2010/06/16 13:51), Rusty Russell wrote: > > drivers/pci/pci.c:2277: error: redefinition of ‘pci_msi_off’ > > include/linux/pci.h:786: note: previous definition of ‘pci_msi_off’ was here > > > > Signed-off-by: Rusty Russell > > --- > > drivers/pci/pci.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -2266,6 +2266,7 @@ pci_intx(struct pci_dev *pdev, int enabl > > } > > } > > > > +#ifdef CONFIG_PCI_MSI > > /** > > * pci_msi_off - disables any msi or msix capabilities > > * @dev: the PCI device to operate on > > @@ -2293,6 +2294,7 @@ void pci_msi_off(struct pci_dev *dev) > > } > > } > > EXPORT_SYMBOL_GPL(pci_msi_off); > > +#endif > > > > #ifndef HAVE_ARCH_PCI_SET_DMA_MAX_SEGMENT_SIZE > > int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size) > > Rusty, thank you for reporting it. > But I think this fix is not correct. > > It looks like a bug in Michael's patch: > [PATCH for-2.6.35] virtio-pci: disable msi at startup > > The patch includes a change as following: > > > > --- a/include/linux/pci.h > > > +++ b/include/linux/pci.h > > > @@ -780,7 +780,11 @@ int __must_check pci_set_mwi(struct pci_dev *dev); > > > int pci_try_set_mwi(struct pci_dev *dev); > > > void pci_clear_mwi(struct pci_dev *dev); > > > void pci_intx(struct pci_dev *dev, int enable); > > > +#ifdef CONFIG_PCI_MSI > > > void pci_msi_off(struct pci_dev *dev); > > > +#else > > > +static inline void pci_msi_off(struct pci_dev *dev) {} > > > +#endif > > > int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size); > > > int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask); > > > int pcix_get_max_mmrbc(struct pci_dev *dev); > > According to the old commit f5f2b13129a6541debf8851bae843cbbf48298b7, > pci_msi_off() was designed to be available even when msi support is not > compiled in. So I think this change will make something wrong. > > Michael, could you check your patch? > > > Thanks, > H.Seto You are right. I didn't think this through: we must disable the capability at startup even if the current kernel does not support MSI, otherwise the device won't work. Please apply this on top. Signed-off-by: Michael S. Tsirkin --- diff --git a/include/linux/pci.h b/include/linux/pci.h index 31d8a12..7cb0084 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -780,11 +780,7 @@ int __must_check pci_set_mwi(struct pci_dev *dev); int pci_try_set_mwi(struct pci_dev *dev); void pci_clear_mwi(struct pci_dev *dev); void pci_intx(struct pci_dev *dev, int enable); -#ifdef CONFIG_PCI_MSI void pci_msi_off(struct pci_dev *dev); -#else -static inline void pci_msi_off(struct pci_dev *dev) {} -#endif int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size); int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask); int pcix_get_max_mmrbc(struct pci_dev *dev); -- 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/