[PATCH] ocxl: fix pci device refcount leak when calling get_function_0()

[Yang Yingliang]

As comment of pci_get_domain_bus_and_slot() says, it returns
a pci device with refcount increment, so when finish using it,
pci_dev_put() needs be called.

In get_dvsec_vendor0(), in normal path, the returned pci device
is passed to dev0, so after using dev0 in the callers, it need
be put, in error path, pci_dev_put() also needs be called.

pci_get_domain_bus_and_slot() is called when PCI_FUNC() returns
non-zero, check this before put.

Fixes: 87db7579ebd5 ("ocxl: control via sysfs whether the FPGA is reloaded on a link reset")
Signed-off-by: Yang Yingliang <yangyingliang at huawei.com>
---
 drivers/misc/ocxl/config.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ocxl/config.c b/drivers/misc/ocxl/config.c
index e401a51596b9..4da5a2b8514c 100644
--- a/drivers/misc/ocxl/config.c
+++ b/drivers/misc/ocxl/config.c
@@ -196,16 +196,21 @@ static int read_dvsec_vendor(struct pci_dev *dev)
 static int get_dvsec_vendor0(struct pci_dev *dev, struct pci_dev **dev0,
 			     int *out_pos)
 {
+	bool need_put;
 	int pos;
 
 	if (PCI_FUNC(dev->devfn) != 0) {
 		dev = get_function_0(dev);
 		if (!dev)
 			return -1;
+		need_put = true;
 	}
 	pos = find_dvsec(dev, OCXL_DVSEC_VENDOR_ID);
-	if (!pos)
+	if (!pos) {
+		if (need_put)
+			pci_dev_put(dev);
 		return -1;
+	}
 	*dev0 = dev;
 	*out_pos = pos;
 	return 0;
@@ -222,6 +227,8 @@ int ocxl_config_get_reset_reload(struct pci_dev *dev, int *val)
 
 	pci_read_config_dword(dev0, pos + OCXL_DVSEC_VENDOR_RESET_RELOAD,
 			      &reset_reload);
+	if (PCI_FUNC(dev->devfn) != 0)
+		pci_dev_put(dev0);
 	*val = !!(reset_reload & BIT(0));
 	return 0;
 }
@@ -243,6 +250,8 @@ int ocxl_config_set_reset_reload(struct pci_dev *dev, int val)
 		reset_reload &= ~BIT(0);
 	pci_write_config_dword(dev0, pos + OCXL_DVSEC_VENDOR_RESET_RELOAD,
 			       reset_reload);
+	if (PCI_FUNC(dev->devfn) != 0)
+		pci_dev_put(dev0);
 	return 0;
 }
 
-- 
2.25.1