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, 39 insertions, 0 deletions

diff --git a/drivers/interconnect/qcom/icc-common.c b/drivers/interconnect/qcom/icc-common.c
new file mode 100644
index 000000000..a25564fe1
--- /dev/null
+++ b/drivers/interconnect/qcom/icc-common.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include "icc-common.h"
+
+struct icc_node_data *qcom_icc_xlate_extended(const struct of_phandle_args *spec,
+					      void *data)
+{
+	struct icc_node_data *ndata;
+	struct icc_node *node;
+
+	node = of_icc_xlate_onecell(spec, data);
+	if (IS_ERR(node))
+		return ERR_CAST(node);
+
+	ndata = kzalloc_obj(*ndata);
+	if (!ndata)
+		return ERR_PTR(-ENOMEM);
+
+	ndata->node = node;
+
+	if (spec->args_count == 2)
+		ndata->tag = spec->args[1];
+
+	if (spec->args_count > 2)
+		pr_warn("%pOF: Too many arguments, path tag is not parsed\n", spec->np);
+
+	return ndata;
+}
+EXPORT_SYMBOL_GPL(qcom_icc_xlate_extended);
+
+MODULE_DESCRIPTION("Qualcomm interconnect common functions");
+MODULE_LICENSE("GPL");