[PATCH 1/2] pci: Cache the VF device ID in the SR-IOV structure

From: Filippo Sironi
Date: Mon Aug 28 2017 - 09:39:55 EST


... and use it instead of reading it over and over from the PF config
space capability.

Signed-off-by: Filippo Sironi <sironi@xxxxxxxxx>
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/pci/iov.c | 5 +++--
drivers/pci/pci.h | 1 +
2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 120485d6f352..e8f7eafaba6a 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -134,7 +134,7 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset)

virtfn->devfn = pci_iov_virtfn_devfn(dev, id);
virtfn->vendor = dev->vendor;
- pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
+ virtfn->device = iov->vf_did;
rc = pci_setup_device(virtfn);
if (rc)
goto failed0;
@@ -448,6 +448,7 @@ static int sriov_init(struct pci_dev *dev, int pos)
iov->nres = nres;
iov->ctrl = ctrl;
iov->total_VFs = total;
+ pci_read_config_word(dev, pos + PCI_SRIOV_VF_DID, &iov->vf_did);
iov->pgsz = pgsz;
iov->self = dev;
iov->drivers_autoprobe = true;
@@ -723,7 +724,7 @@ int pci_vfs_assigned(struct pci_dev *dev)
* determine the device ID for the VFs, the vendor ID will be the
* same as the PF so there is no need to check for that one
*/
- pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_VF_DID, &dev_id);
+ dev_id = dev->sriov->vf_did;

/* loop through all the VFs to see if we own any that are assigned */
vfdev = pci_get_device(dev->vendor, dev_id, NULL);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 22e061738c6f..a7270e11e1ef 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -262,6 +262,7 @@ struct pci_sriov {
u16 num_VFs; /* number of VFs available */
u16 offset; /* first VF Routing ID offset */
u16 stride; /* following VF stride */
+ u16 vf_did; /* VF device ID */
u32 pgsz; /* page size for BAR alignment */
u8 link; /* Function Dependency Link */
u8 max_VF_buses; /* max buses consumed by VFs */
--
2.7.4