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, 65 insertions, 0 deletions

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
new file mode 100644
index 000000000..f71775090
--- /dev/null
+++ b/net/mptcp/fastopen.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+/* MPTCP Fast Open Mechanism
+ *
+ * Copyright (c) 2021-2022, Dmytro SHYTYI
+ */
+
+#include "protocol.h"
+
+void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
+					      struct request_sock *req)
+{
+	struct sock *sk, *ssk;
+	struct sk_buff *skb;
+	struct tcp_sock *tp;
+	bool has_rxtstamp;
+
+	/* on early fallback the subflow context is deleted by
+	 * subflow_syn_recv_sock()
+	 */
+	if (!subflow)
+		return;
+
+	ssk = subflow->tcp_sock;
+	sk = subflow->conn;
+	tp = tcp_sk(ssk);
+
+	/* A valid TFO cookie does not guarantee SYN data. */
+	skb = skb_peek(&ssk->sk_receive_queue);
+	if (!skb)
+		return;
+
+	subflow->is_mptfo = 1;
+
+	/* dequeue the skb from sk receive queue */
+	__skb_unlink(skb, &ssk->sk_receive_queue);
+	skb_ext_reset(skb);
+
+	mptcp_subflow_lend_fwdmem(subflow, skb);
+
+	/* We copy the fastopen data, but that don't belong to the mptcp sequence
+	 * space, need to offset it in the subflow sequence, see mptcp_subflow_get_map_offset()
+	 */
+	tp->copied_seq += skb->len;
+	subflow->ssn_offset += skb->len;
+	has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
+
+	/* Only the sequence delta is relevant */
+	MPTCP_SKB_CB(skb)->map_seq = -skb->len;
+	MPTCP_SKB_CB(skb)->end_seq = 0;
+	MPTCP_SKB_CB(skb)->offset = 0;
+	MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
+	MPTCP_SKB_CB(skb)->cant_coalesce = 1;
+
+	mptcp_data_lock(sk);
+	DEBUG_NET_WARN_ON_ONCE(sock_owned_by_user_nocheck(sk));
+
+	mptcp_borrow_fwdmem(sk, skb);
+	skb_set_owner_r(skb, sk);
+	__skb_queue_tail(&sk->sk_receive_queue, skb);
+	mptcp_sk(sk)->bytes_received += skb->len;
+
+	sk->sk_data_ready(sk);
+
+	mptcp_data_unlock(sk);
+}