x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 73 insertions, 0 deletions

diff --git a/net/nfc/nci/lib.c b/net/nfc/nci/lib.c
new file mode 100644
index 000000000..473323f80
--- /dev/null
+++ b/net/nfc/nci/lib.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  The NFC Controller Interface is the communication protocol between an
+ *  NFC Controller (NFCC) and a Device Host (DH).
+ *
+ *  Copyright (C) 2011 Texas Instruments, Inc.
+ *
+ *  Written by Ilan Elias <ilane@ti.com>
+ *
+ *  Acknowledgements:
+ *  This file is based on lib.c, which was written
+ *  by Maxim Krasnyansky.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+
+#include <net/nfc/nci.h>
+#include <net/nfc/nci_core.h>
+
+/* NCI status codes to Unix errno mapping */
+int nci_to_errno(__u8 code)
+{
+	switch (code) {
+	case NCI_STATUS_OK:
+		return 0;
+
+	case NCI_STATUS_REJECTED:
+		return -EBUSY;
+
+	case NCI_STATUS_RF_FRAME_CORRUPTED:
+		return -EBADMSG;
+
+	case NCI_STATUS_NOT_INITIALIZED:
+		return -EHOSTDOWN;
+
+	case NCI_STATUS_SYNTAX_ERROR:
+	case NCI_STATUS_SEMANTIC_ERROR:
+	case NCI_STATUS_INVALID_PARAM:
+	case NCI_STATUS_RF_PROTOCOL_ERROR:
+	case NCI_STATUS_NFCEE_PROTOCOL_ERROR:
+		return -EPROTO;
+
+	case NCI_STATUS_UNKNOWN_GID:
+	case NCI_STATUS_UNKNOWN_OID:
+		return -EBADRQC;
+
+	case NCI_STATUS_MESSAGE_SIZE_EXCEEDED:
+		return -EMSGSIZE;
+
+	case NCI_STATUS_DISCOVERY_ALREADY_STARTED:
+		return -EALREADY;
+
+	case NCI_STATUS_DISCOVERY_TARGET_ACTIVATION_FAILED:
+	case NCI_STATUS_NFCEE_INTERFACE_ACTIVATION_FAILED:
+		return -ECONNREFUSED;
+
+	case NCI_STATUS_RF_TRANSMISSION_ERROR:
+	case NCI_STATUS_NFCEE_TRANSMISSION_ERROR:
+		return -ECOMM;
+
+	case NCI_STATUS_RF_TIMEOUT_ERROR:
+	case NCI_STATUS_NFCEE_TIMEOUT_ERROR:
+		return -ETIMEDOUT;
+
+	case NCI_STATUS_FAILED:
+	default:
+		return -ENOSYS;
+	}
+}
+EXPORT_SYMBOL(nci_to_errno);