[RFC PATCH] cxl: Use pci_find_vsec_capability() to simplify the code

[Xiongfeng Wang]

PCI core add pci_find_vsec_capability() to query VSEC. We can use that
core API to simplify the code.

The only logical change is that pci_find_vsec_capability check the
Vendor ID before finding the VSEC.

PCI spec rev 5.0 says in 7.9.5.2 Vendor-Specific Header:
  VSEC ID - This field is a vendor-defined ID number that indicates the
  nature and format of the VSEC structure
  Software must qualify the Vendor ID before interpreting this field.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2 at huawei.com>
---
 drivers/misc/cxl/pci.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 0ff944860dda..f3108977755d 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -150,16 +150,8 @@ static inline resource_size_t p2_size(struct pci_dev *dev)
 
 static int find_cxl_vsec(struct pci_dev *dev)
 {
-	int vsec = 0;
-	u16 val;
-
-	while ((vsec = pci_find_next_ext_capability(dev, vsec, PCI_EXT_CAP_ID_VNDR))) {
-		pci_read_config_word(dev, vsec + 0x4, &val);
-		if (val == CXL_PCI_VSEC_ID)
-			return vsec;
-	}
-	return 0;
-
+	return pci_find_vsec_capability(dev, PCI_VENDOR_ID_IBM,
+					CXL_PCI_VSEC_ID);
 }
 
 static void dump_cxl_config_space(struct pci_dev *dev)
-- 
2.20.1