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, 112 insertions, 0 deletions

diff --git a/net/mac80211/rate.h b/net/mac80211/rate.h
new file mode 100644
index 000000000..5e4bde598
--- /dev/null
+++ b/net/mac80211/rate.h
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2002-2005, Instant802 Networks, Inc.
+ * Copyright 2005, Devicescape Software, Inc.
+ * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
+ * Copyright (C) 2022, 2024 Intel Corporation
+ */
+
+#ifndef IEEE80211_RATE_H
+#define IEEE80211_RATE_H
+
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/types.h>
+#include <net/mac80211.h>
+#include "ieee80211_i.h"
+#include "sta_info.h"
+#include "driver-ops.h"
+
+struct rate_control_ref {
+	const struct rate_control_ops *ops;
+	void *priv;
+};
+
+void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
+			   struct sta_info *sta,
+			   struct ieee80211_tx_rate_control *txrc);
+
+void rate_control_tx_status(struct ieee80211_local *local,
+			    struct ieee80211_tx_status *st);
+
+void rate_control_rate_init(struct link_sta_info *link_sta);
+void rate_control_rate_init_all_links(struct sta_info *sta);
+void rate_control_rate_update(struct ieee80211_local *local,
+			      struct ieee80211_supported_band *sband,
+			      struct link_sta_info *link_sta,
+			      u32 changed);
+
+static inline void *rate_control_alloc_sta(struct rate_control_ref *ref,
+					   struct sta_info *sta, gfp_t gfp)
+{
+	spin_lock_init(&sta->rate_ctrl_lock);
+	return ref->ops->alloc_sta(ref->priv, &sta->sta, gfp);
+}
+
+static inline void rate_control_free_sta(struct sta_info *sta)
+{
+	struct rate_control_ref *ref = sta->rate_ctrl;
+	struct ieee80211_sta *ista = &sta->sta;
+	void *priv_sta = sta->rate_ctrl_priv;
+
+	ref->ops->free_sta(ref->priv, ista, priv_sta);
+}
+
+static inline void rate_control_add_sta_debugfs(struct sta_info *sta)
+{
+#ifdef CONFIG_MAC80211_DEBUGFS
+	struct rate_control_ref *ref = sta->rate_ctrl;
+	if (ref && sta->debugfs_dir && ref->ops->add_sta_debugfs)
+		ref->ops->add_sta_debugfs(ref->priv, sta->rate_ctrl_priv,
+					  sta->debugfs_dir);
+#endif
+}
+
+extern const struct debugfs_short_fops rcname_ops;
+
+static inline void rate_control_add_debugfs(struct ieee80211_local *local)
+{
+#ifdef CONFIG_MAC80211_DEBUGFS
+	struct dentry *debugfsdir;
+
+	if (!local->rate_ctrl)
+		return;
+
+	if (!local->rate_ctrl->ops->add_debugfs)
+		return;
+
+	debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
+	local->debugfs.rcdir = debugfsdir;
+	debugfs_create_file("name", 0400, debugfsdir,
+			    local->rate_ctrl, &rcname_ops);
+
+	local->rate_ctrl->ops->add_debugfs(&local->hw, local->rate_ctrl->priv,
+					   debugfsdir);
+#endif
+}
+
+void ieee80211_check_rate_mask(struct ieee80211_link_data *link);
+
+/* Get a reference to the rate control algorithm. If `name' is NULL, get the
+ * first available algorithm. */
+int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
+				 const char *name);
+void rate_control_deinitialize(struct ieee80211_local *local);
+
+
+/* Rate control algorithms */
+#ifdef CONFIG_MAC80211_RC_MINSTREL
+int rc80211_minstrel_init(void);
+void rc80211_minstrel_exit(void);
+#else
+static inline int rc80211_minstrel_init(void)
+{
+	return 0;
+}
+static inline void rc80211_minstrel_exit(void)
+{
+}
+#endif
+
+
+#endif /* IEEE80211_RATE_H */