2014-11-28 16:13, Jincheng Miao: > > 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. > > > > Please, could you explain in which case CONFIG_PCI_IOV is defined? > > The logic is a bit difficult to understand. > > 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 >= > RHEL_RELEASE_VERSION(6, 0) && defined(CONFIG_PCI_IOV))) > > Firstly it detects kernel version, if it is less than 2.6.34, and it is > not RHEL-specified, then define pci_num_vf(). > > Secondly, it deals with RHEL-specified. If it is RHEL6.0 or later, and > CONFIG_PCI_IOV is defined. we should not define pci_num_vf(). If any of > 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 error: > ``` > CC [M] > /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: > In function ?show_max_vfs?: > /root/dpdk-source/build/build/lib/librte_eal/linuxapp/igb_uio/igb_uio.c:75: > error: implicit declaration of function ?pci_num_vf? > ``` Thank you. Describing the problem is helpful for the commit log. > This problem is introduced by commit 11ba04265 > > commit 11ba04265cfd2a53c12c030fcaa5dfe7eed39a42 > Author: Guillaume Gaudonville <guillaume.gaudonville at 6wind.com> > Date: Wed Sep 3 10:18:23 2014 +0200 > > igb_uio: fix build on RHEL 6.3 > > - 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 > > Signed-off-by: Guillaume Gaudonville <guillaume.gaudonville at 6wind.com> > Signed-off-by: David Marchand <david.marchand at 6wind.com> > Signed-off-by: Thomas Monjalon <thomas.monjalon at 6wind.com> > > +#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 34) && \ > + !defined(CONFIG_PCI_IOV) > > That is because longterm kernel 2.6.32.63 defined CONFIG_PCI_IOV, but it > lacks pci_num_vf(), > after above processing, pci_num_vf() is still not existed, then build fail. > > My patch could work around it, and can deal with RHEL-specified kernel. Thanks, we just need to understand the matrix of combinations to be sure it will be well maintained. -- Thomas