Re: [RFC Patch 01/12] PCI: Add virtfn_index for struct pci_device

From: Alexander Duyck
Date: Wed Oct 21 2015 - 14:07:30 EST


On 10/21/2015 09:37 AM, Lan Tianyu wrote:
Add "virtfn_index" member in the struct pci_device to record VF sequence
of PF. This will be used in the VF sysfs node handle.

Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
drivers/pci/iov.c | 1 +
include/linux/pci.h | 1 +
2 files changed, 2 insertions(+)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index ee0ebff..065b6bb 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -136,6 +136,7 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset)
virtfn->physfn = pci_dev_get(dev);
virtfn->is_virtfn = 1;
virtfn->multifunction = 0;
+ virtfn->virtfn_index = id;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = &dev->resource[i + PCI_IOV_RESOURCES];
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 353db8d..85c5531 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -356,6 +356,7 @@ struct pci_dev {
unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */
unsigned int irq_managed:1;
pci_dev_flags_t dev_flags;
+ unsigned int virtfn_index;
atomic_t enable_cnt; /* pci_enable_device has been called */
u32 saved_config_space[16]; /* config space saved at suspend time */


Can't you just calculate the VF index based on the VF BDF number combined with the information in the PF BDF number and VF offset/stride? Seems kind of pointless to add a variable that is only used by one driver and is in a slowpath when you can just calculate it pretty quickly.

- Alex
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