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. 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. 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? ``` 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. >> #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 34) && \ >> - !defined(CONFIG_PCI_IOV) >> + (!(defined(RHEL_RELEASE_CODE) && \ >> + RHEL_RELEASE_CODE >= RHEL_RELEASE_VERSION(6, 0) && \ >> + defined(CONFIG_PCI_IOV))) >> >> static int pci_num_vf(struct pci_dev *dev) >> {