From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH v2 1/2] igb_uio: compatible with upstream longterm kernel and RHEL6 Date: Fri, 28 Nov 2014 17:42:48 +0100 Message-ID: <3179225.WT7VCi68g0@xps13> References: <1414741039-3531-1-git-send-email-jmiao@redhat.com> <7579030.6nSHmmQ36o@xps13> <54782EB5.7060409@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Cc: dev-VfR2kkLFssw@public.gmane.org To: Jincheng Miao Return-path: In-Reply-To: <54782EB5.7060409-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" 2014-11-28 16:13, Jincheng Miao: >=20 > On 11/28/2014 01:01 AM, Thomas Monjalon wrote: > > 2014-10-31 15:37, Jincheng Miao: > >> Function pci_num_vf() is introduced from upstream linux-2.6.34. So= > >> this patch make compatible with longterm kernel linux-2.6.32.63. > >> > >> For RHEL6's kernel, although it is based on linux-2.6.32, it has > >> pci_num_vf() implementation. As the same with commit 11ba0426, > >> pci_num_vf() is defined from RHEL6. So we should check the macro > >> RHEL_RELEASE_CODE to consider this situation. > >=20 > > Please, could you explain in which case CONFIG_PCI_IOV is defined? > > The logic is a bit difficult to understand. >=20 > Yep, there is a little confusion for pci_num_vf(): > 1. it is available when CONFIG_PCI_IOV is defined. > 2. it is introduced from upstream kernel v2.6.34 (fb8a0d9) > 3. it is implemented from RHEL6.0, although the kernel version is 2.6= .32. Sorry, you didn't described when CONFIG_PCI_IOV is defined. Is it defined since 2.6.34 upstream? In lower stable versions? Is it defined since RHEL 6.0? Why checking CONFIG_PCI_IOV is not sufficient? When pci_num_vf will be backported in other distributions, we will have= to tune this check and clearly understand what was the situation. > The logic of this patch is: > #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 34) && \ > (!(defined(RHEL_RELEASE_CODE) && RHEL_RELEASE_CODE >=3D=20 > RHEL_RELEASE_VERSION(6, 0) && defined(CONFIG_PCI_IOV))) >=20 > Firstly it detects kernel version, if it is less than 2.6.34, and it = is=20 > not RHEL-specified, then define pci_num_vf(). >=20 > Secondly, it deals with RHEL-specified. If it is RHEL6.0 or later, an= d=20 > CONFIG_PCI_IOV is defined. we should not define pci_num_vf(). If any = of=20 > these conditions is not reached, pci_num_vf() should be defined. I can read the check but I don't know why CONFIG_PCI_IOV is checked in = the RHEL case. > Some days ago, I setup dpdk for longterm kernel 2.6.32.63, and got er= ror: > ``` > CC [M]=20 > /root/dpdk-source/build/build/lib/librte_eal/linuxapp/igb_uio/igb_uio= .o > /root/dpdk-source/build/build/lib/librte_eal/linuxapp/igb_uio/igb_uio= .c:=20 > In function =E2=80=98show_max_vfs=E2=80=99: > /root/dpdk-source/build/build/lib/librte_eal/linuxapp/igb_uio/igb_uio= .c:75:=20 > error: implicit declaration of function =E2=80=98pci_num_vf=E2=80=99 > ``` Thank you. Describing the problem is helpful for the commit log. =20 > This problem is introduced by commit 11ba04265 >=20 > commit 11ba04265cfd2a53c12c030fcaa5dfe7eed39a42 > Author: Guillaume Gaudonville > Date: Wed Sep 3 10:18:23 2014 +0200 >=20 > igb_uio: fix build on RHEL 6.3 >=20 > - pci_num_vf() is already defined in RHEL 6 > - pci_intx_mask_supported is already defined in RHEL 6.3 > - pci_check_and_mask_intx is already defined in RHEL 6.3 >=20 > Signed-off-by: Guillaume Gaudonville > Signed-off-by: David Marchand > Signed-off-by: Thomas Monjalon >=20 > +#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 34) && \ > + !defined(CONFIG_PCI_IOV) >=20 > That is because longterm kernel 2.6.32.63 defined CONFIG_PCI_IOV, but= it=20 > lacks pci_num_vf(), > after above processing, pci_num_vf() is still not existed, then build= fail. >=20 > My patch could work around it, and can deal with RHEL-specified kerne= l. Thanks, we just need to understand the matrix of combinations to be sur= e it will be well maintained. --=20 Thomas