PCI/VPD: Add pci_vpd_alloc()

Several users of the VPD API use a fixed-size buffer and read the VPD into
it for further usage. This requires special handling for the case that the
buffer isn't big enough to hold the full VPD data.  Also the buffer is
often allocated on the stack, which isn't too nice.

Add pci_vpd_alloc() to dynamically allocate buffer of the correct size and
read VPD into it.

Link: https://lore.kernel.org/r/955ff598-0021-8446-f856-0c2c077635d7@gmail.com
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index 3b0425fb49f5..7c3a097379bb 100644
--- a/drivers/pci/vpd.c
+++ b/drivers/pci/vpd.c
@@ -270,6 +270,32 @@ const struct attribute_group pci_dev_vpd_attr_group = {
 	.is_bin_visible = vpd_attr_is_visible,
 };
 
+void *pci_vpd_alloc(struct pci_dev *dev, unsigned int *size)
+{
+	unsigned int len = dev->vpd.len;
+	void *buf;
+	int cnt;
+
+	if (!dev->vpd.cap)
+		return ERR_PTR(-ENODEV);
+
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	cnt = pci_read_vpd(dev, 0, len, buf);
+	if (cnt != len) {
+		kfree(buf);
+		return ERR_PTR(-EIO);
+	}
+
+	if (size)
+		*size = len;
+
+	return buf;
+}
+EXPORT_SYMBOL_GPL(pci_vpd_alloc);
+
 int pci_vpd_find_tag(const u8 *buf, unsigned int len, u8 rdt)
 {
 	int i = 0;