Messages in this thread | | | Subject | Re: [PATCH v4 2/7] PCI/ATS: Initialize PRI in pci_ats_init() | From | sathyanarayanan kuppuswamy <> | Date | Thu, 1 Aug 2019 14:21:07 -0700 |
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Hi Keith,
Thanks for the review.
On 8/1/19 2:09 PM, Keith Busch wrote: > On Wed, Jul 03, 2019 at 01:46:19PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote: >> +#ifdef CONFIG_PCI_PRI >> +static void pci_pri_init(struct pci_dev *pdev) >> +{ >> + u32 max_requests; >> + int pos; >> + >> + /* >> + * As per PCIe r4.0, sec 9.3.7.11, only PF is permitted to >> + * implement PRI and all associated VFs can only use it. >> + * Since PF already initialized the PRI parameters there is >> + * no need to proceed further. >> + */ >> + if (pdev->is_virtfn) >> + return; >> + >> + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI); >> + if (!pos) >> + return; >> + >> + pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests); >> + >> + /* >> + * Since PRI is a shared resource between PF and VF, we must not >> + * configure Outstanding Page Allocation Quota as a per device >> + * resource in pci_enable_pri(). So use maximum value possible >> + * as default value. >> + */ >> + pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, max_requests); >> + >> + pdev->pri_reqs_alloc = max_requests; >> + pdev->pri_cap = pos; >> +} >> +#endif >> + >> void pci_ats_init(struct pci_dev *dev) >> { >> int pos; >> @@ -28,6 +62,10 @@ void pci_ats_init(struct pci_dev *dev) >> return; >> >> dev->ats_cap = pos; >> + >> +#ifdef CONFIG_PCI_PRI >> + pci_pri_init(dev); >> +#endif >> } > Rather than surround the call to pci_pri_init() with the #ifdef, you > should provide an empty function implementation when CONFIG_PCI_PRI is > not defined. Same thing for the next patch adding PASID. This function is defined and used in the same file (ats.c). Is there any advantage in defining an empty function ? But if this is the recommended approach, I can make the necessary changes. Please confirm. > -- Sathyanarayanan Kuppuswamy Linux kernel developer
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