From 3ad62192097443e8c3a8e244475bacaecb894d4e Mon Sep 17 00:00:00 2001 From: Kuppuswamy Sathyanarayanan Date: Thu, 5 Sep 2019 14:31:44 -0500 Subject: [PATCH] PCI/ATS: Disable PF/VF ATS service independently Previously we didn't disable the PF ATS until all associated VFs had disabled it. But per PCIe spec r5.0, sec 9.3.7.8, the ATS Capability in VFs and associated PFs may be enabled independently. Leaving ATS enabled in the PF unnecessarily may have power and performance impacts. Remove this dependency logic in the ATS enable/disable code. [bhelgaas: commit log] Suggested-by: Ashok Raj Link: https://lore.kernel.org/r/8163ab8fa66afd2cba514ae95d29ab12104781aa.1567029860.git.sathyanarayanan.kuppuswamy@linux.intel.com Link: https://lore.kernel.org/r/20190905193146.90250-4-helgaas@kernel.org Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Bjorn Helgaas Cc: Ashok Raj Cc: Keith Busch --- drivers/pci/ats.c | 11 ----------- include/linux/pci.h | 1 - 2 files changed, 12 deletions(-) diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index fb5cfd27dd3c1..a708ed4146ca2 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -60,8 +60,6 @@ int pci_enable_ats(struct pci_dev *dev, int ps) pdev = pci_physfn(dev); if (pdev->ats_stu != ps) return -EINVAL; - - atomic_inc(&pdev->ats_ref_cnt); /* count enabled VFs */ } else { dev->ats_stu = ps; ctrl |= PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU); @@ -79,20 +77,11 @@ EXPORT_SYMBOL_GPL(pci_enable_ats); */ void pci_disable_ats(struct pci_dev *dev) { - struct pci_dev *pdev; u16 ctrl; if (WARN_ON(!dev->ats_enabled)) return; - if (atomic_read(&dev->ats_ref_cnt)) - return; /* VFs still enabled */ - - if (dev->is_virtfn) { - pdev = pci_physfn(dev); - atomic_dec(&pdev->ats_ref_cnt); - } - pci_read_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, &ctrl); ctrl &= ~PCI_ATS_CTRL_ENABLE; pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl); diff --git a/include/linux/pci.h b/include/linux/pci.h index f9088c89a5347..c028883c8460c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -452,7 +452,6 @@ struct pci_dev { }; u16 ats_cap; /* ATS Capability offset */ u8 ats_stu; /* ATS Smallest Translation Unit */ - atomic_t ats_ref_cnt; /* Number of VFs with ATS enabled */ #endif #ifdef CONFIG_PCI_PRI u32 pri_reqs_alloc; /* Number of PRI requests allocated */ -- 2.30.2