On Tue, Sep 14, 2021 at 07:07:40PM +0200, Heiner Kallweit wrote:
> On 14.09.2021 13:26, Bjorn Helgaas wrote:
> > On Tue, Sep 14, 2021 at 08:21:46AM +0200, Heiner Kallweit wrote:
> >> On 14.09.2021 01:46, Bjorn Helgaas wrote:
> >
> >>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATTANSIC, PCI_ANY_ID, quirk_blacklist_vpd);
> >>> /*
> >>
> >> Leaving the quirks in FIXUP_HEADER stage would have the advantage that for
> >> blacklisted devices the vpd sysfs attribute isn't visibale. The needed
> >> changes to the patch are minimal.
> >
> > What do you have in mind? The only thing I can think of would be to
> > add a "pci_dev.no_vpd" bit. "vpd.cap == 0" means the device has no
> > VPD, and "vpd.len == 0" means we haven't determined the size yet. All
> > devices start off with vpd.cap == 0 and vpd.len == 0, so a
> > FIXUP_HEADER quirk would have to set a sentinel value or some other
> > bit.
>
> Why not leave vpd.len == PCI_VPD_SZ_INVALID as sentinel?
Sentinel values aren't really my favorite thing, but it certainly does
have the advantage of hiding the sysfs attribute.
> And one more question: Why do you move the "if (!vpd->cap)" check from
> pci_vpd_read() to pci_read_vpd()? At a first glance I see no benefit.
I'm pretty sure I *had* a reason, but I can't remember right now :(
Moving it sure does uglify pci_read_vpd() and pci_write_vpd(), though.
What do you think of the following? (This is a diff from v5.15-rc1.)
diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index 25557b272a4f..4be24890132e 100644
--- a/drivers/pci/vpd.c
+++ b/drivers/pci/vpd.c
@@ -99,6 +99,24 @@ static size_t pci_vpd_size(struct pci_dev *dev)
return off ?: PCI_VPD_SZ_INVALID;
}
+static bool pci_vpd_available(struct pci_dev *dev)
+{
+ struct pci_vpd *vpd = &dev->vpd;
+
+ if (!vpd->cap)
+ return false;
+
+ if (vpd->len == 0) {
+ vpd->len = pci_vpd_size(dev);
+ if (vpd->len == PCI_VPD_SZ_INVALID) {
+ vpd->cap = 0;
+ return false;
+ }
+ }
+
+ return true;
+}
+
/*
* Wait for last operation to complete.
* This code has to spin since there is no other notification from the PCI
@@ -145,7 +163,7 @@ static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,
loff_t end = pos + count;
u8 *buf = arg;
- if (!vpd->cap)
+ if (!pci_vpd_available(dev))
return -ENODEV;
if (pos < 0)
@@ -206,7 +224,7 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
loff_t end = pos + count;
int ret = 0;
- if (!vpd->cap)
+ if (!pci_vpd_available(dev))
return -ENODEV;
if (pos < 0 || (pos & 3) || (count & 3))
@@ -242,14 +260,11 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
void pci_vpd_init(struct pci_dev *dev)
{
+ if (dev->vpd.len == PCI_VPD_SZ_INVALID)
+ return;
+
dev->vpd.cap = pci_find_capability(dev, PCI_CAP_ID_VPD);
mutex_init(&dev->vpd.lock);
-
- if (!dev->vpd.len)
- dev->vpd.len = pci_vpd_size(dev);
-
- if (dev->vpd.len == PCI_VPD_SZ_INVALID)
- dev->vpd.cap = 0;
}
static ssize_t vpd_read(struct file *filp, struct kobject *kobj,
@@ -294,13 +309,14 @@ const struct attribute_group pci_dev_vpd_attr_group = {
void *pci_vpd_alloc(struct pci_dev *dev, unsigned int *size)
{
- unsigned int len = dev->vpd.len;
+ unsigned int len;
void *buf;
int cnt;
- if (!dev->vpd.cap)
+ if (!pci_vpd_available(dev))
return ERR_PTR(-ENODEV);
+ len = dev->vpd.len;
buf = kmalloc(len, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
