[v5,6/7] PCI/ATS: Disable PF/VF ATS service independently
diff mbox series

Message ID 2407a2a39a4bb1e3904ebfda8ebaec3d88741082.1564702313.git.sathyanarayanan.kuppuswamy@linux.intel.com
State Superseded
Delegated to: Bjorn Helgaas
Headers show
Series
  • Fix PF/VF dependency issue
Related show

Commit Message

Kuppuswamy Sathyanarayanan Aug. 2, 2019, 12:06 a.m. UTC
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Currently all VF's needs to be disable their ATS service before
disabling the ATS service in corresponding PF device. But this logic is
incorrect and does not align with the spec. Also it might lead to
some power and performance impact in the system. As per PCIe spec r4.0,
sec 9.3.7.8, ATS Capabilities in VFs and their associated PFs may be
enabled/disabled independently. So remove this dependency logic in
enable/disable code.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/ats.c   | 11 -----------
 include/linux/pci.h |  1 -
 2 files changed, 12 deletions(-)

Patch
diff mbox series

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 9384afd7d00e..df2d20079e38 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -64,8 +64,6 @@  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);
@@ -83,20 +81,11 @@  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 4bfcca045afd..84301db2fbef 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
 	struct mutex	pri_lock;	/* PRI enable lock */