[PATCH 1/8] PCI/VPD: Add pci_vpd_alloc

[Heiner Kallweit <hkallweit1@gmail.com>]

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 what's not too nice.
So let's extend the VPD API with a function that dynamically allocates
a properly sized buffer.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/pci/vpd.c   | 26 ++++++++++++++++++++++++++
 include/linux/pci.h |  9 +++++++++
 2 files changed, 35 insertions(+)

diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index 3b0425fb4..7c3a09737 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;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index e752cc39a..3061cc943 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2330,6 +2330,15 @@ static inline u8 pci_vpd_info_field_size(const u8 *info_field)
 	return info_field[2];
 }
 
+/**
+ * pci_vpd_alloc - Allocates buffer and reads VPD into it
+ * @dev: PCI device
+ * @size: pointer to field where VPD length is returned
+ *
+ * Returns pointer to allocated buffer or an ERR_PTR in case of failure
+ */
+void *pci_vpd_alloc(struct pci_dev *dev, unsigned int *size);
+
 /**
  * pci_vpd_find_tag - Locates the Resource Data Type tag provided
  * @buf: Pointer to buffered vpd data
-- 
2.32.0