iommu/vt-d: Fix PCI device refcount leak in has_external_pci()

[ Upstream commit afca9e19cc ]

for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.

If we break for_each_pci_dev() loop with pdev not NULL, we need to call
pci_dev_put() to decrease the reference count. Add the missing
pci_dev_put() before 'return true' to avoid reference count leak.

Fixes: 89a6079df7 ("iommu/vt-d: Force IOMMU on for platform opt in hint")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Link: https://lore.kernel.org/r/20221121113649.190393-2-wangxiongfeng2@huawei.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/iommu/intel/iommu.c

@@ -4241,8 +4241,10 @@ static inline bool has_external_pci(void)
 	struct pci_dev *pdev = NULL;
 
 	for_each_pci_dev(pdev)
-		if (pdev->external_facing)
+		if (pdev->external_facing) {
+			pci_dev_put(pdev);
 			return true;
+		}
 
 	return false;
 }