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, 105 insertions, 0 deletions

diff --git a/net/bluetooth/hci_drv.c b/net/bluetooth/hci_drv.c
new file mode 100644
index 000000000..3dd2d8a00
--- /dev/null
+++ b/net/bluetooth/hci_drv.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 Google Corporation
+ */
+
+#include <linux/skbuff.h>
+#include <linux/types.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/hci_drv.h>
+
+int hci_drv_cmd_status(struct hci_dev *hdev, u16 cmd, u8 status)
+{
+	struct hci_drv_ev_hdr *hdr;
+	struct hci_drv_ev_cmd_status *ev;
+	struct sk_buff *skb;
+
+	skb = bt_skb_alloc(sizeof(*hdr) + sizeof(*ev), GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	hdr = skb_put(skb, sizeof(*hdr));
+	hdr->opcode = __cpu_to_le16(HCI_DRV_EV_CMD_STATUS);
+	hdr->len = __cpu_to_le16(sizeof(*ev));
+
+	ev = skb_put(skb, sizeof(*ev));
+	ev->opcode = __cpu_to_le16(cmd);
+	ev->status = status;
+
+	hci_skb_pkt_type(skb) = HCI_DRV_PKT;
+
+	return hci_recv_frame(hdev, skb);
+}
+EXPORT_SYMBOL(hci_drv_cmd_status);
+
+int hci_drv_cmd_complete(struct hci_dev *hdev, u16 cmd, u8 status, void *rp,
+			 size_t rp_len)
+{
+	struct hci_drv_ev_hdr *hdr;
+	struct hci_drv_ev_cmd_complete *ev;
+	struct sk_buff *skb;
+
+	skb = bt_skb_alloc(sizeof(*hdr) + sizeof(*ev) + rp_len, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	hdr = skb_put(skb, sizeof(*hdr));
+	hdr->opcode = __cpu_to_le16(HCI_DRV_EV_CMD_COMPLETE);
+	hdr->len = __cpu_to_le16(sizeof(*ev) + rp_len);
+
+	ev = skb_put(skb, sizeof(*ev));
+	ev->opcode = __cpu_to_le16(cmd);
+	ev->status = status;
+
+	skb_put_data(skb, rp, rp_len);
+
+	hci_skb_pkt_type(skb) = HCI_DRV_PKT;
+
+	return hci_recv_frame(hdev, skb);
+}
+EXPORT_SYMBOL(hci_drv_cmd_complete);
+
+int hci_drv_process_cmd(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hci_drv_cmd_hdr *hdr;
+	const struct hci_drv_handler *handler = NULL;
+	u16 opcode, len, ogf, ocf;
+
+	hdr = skb_pull_data(skb, sizeof(*hdr));
+	if (!hdr)
+		return -EILSEQ;
+
+	opcode = __le16_to_cpu(hdr->opcode);
+	len = __le16_to_cpu(hdr->len);
+	if (len != skb->len)
+		return -EILSEQ;
+
+	ogf = hci_opcode_ogf(opcode);
+	ocf = hci_opcode_ocf(opcode);
+
+	if (!hdev->hci_drv)
+		return hci_drv_cmd_status(hdev, opcode,
+					  HCI_DRV_STATUS_UNKNOWN_COMMAND);
+
+	if (ogf != HCI_DRV_OGF_DRIVER_SPECIFIC) {
+		if (opcode < hdev->hci_drv->common_handler_count)
+			handler = &hdev->hci_drv->common_handlers[opcode];
+	} else {
+		if (ocf < hdev->hci_drv->specific_handler_count)
+			handler = &hdev->hci_drv->specific_handlers[ocf];
+	}
+
+	if (!handler || !handler->func)
+		return hci_drv_cmd_status(hdev, opcode,
+					  HCI_DRV_STATUS_UNKNOWN_COMMAND);
+
+	if (len != handler->data_len)
+		return hci_drv_cmd_status(hdev, opcode,
+					  HCI_DRV_STATUS_INVALID_PARAMETERS);
+
+	return handler->func(hdev, skb->data, len);
+}
+EXPORT_SYMBOL(hci_drv_process_cmd);