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authorBjorn Helgaas <bhelgaas@google.com>2021-09-14 00:13:26 +0300
committerBjorn Helgaas <bhelgaas@google.com>2021-09-16 00:26:13 +0300
commit00e1a5d21b4ff514593554167b28a8caeda1497f (patch)
treeb0cdf9e81d20a35bdbf3e1efb0e228c7dd28972b /drivers/pci
parent6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f (diff)
downloadlinux-00e1a5d21b4ff514593554167b28a8caeda1497f.tar.xz
PCI/VPD: Defer VPD sizing until first access
7bac54497c3e ("PCI/VPD: Determine VPD size in pci_vpd_init()") reads VPD at enumeration-time to find the size. But this is quite slow, and we don't need the size until we actually need data from VPD. Dave reported a boot slowdown of more than two minutes [1]. Defer the VPD sizing until a driver or the user (via sysfs) requests information from VPD. If devices are quirked because VPD is known not to work, don't bother even looking for the VPD capability. The VPD will not be accessible at all. [1] https://lore.kernel.org/r/20210913141818.GA27911@codemonkey.org.uk/ Link: https://lore.kernel.org/r/20210914215543.GA1437800@bjorn-Precision-5520 Fixes: 7bac54497c3e ("PCI/VPD: Determine VPD size in pci_vpd_init()") Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/vpd.c36
1 files changed, 26 insertions, 10 deletions
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 @@ error:
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);