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

2 files changed, 465 insertions, 0 deletions

diff --git a/include/net/iucv/af_iucv.h b/include/net/iucv/af_iucv.h
new file mode 100644
index 000000000..df85d19fb
--- /dev/null
+++ b/include/net/iucv/af_iucv.h
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2006 IBM Corporation
+ * IUCV protocol stack for Linux on zSeries
+ * Version 1.0
+ * Author(s): Jennifer Hunt <jenhunt@us.ibm.com>
+ *
+ */
+
+#ifndef __AFIUCV_H
+#define __AFIUCV_H
+
+#include <asm/types.h>
+#include <asm/byteorder.h>
+#include <linux/list.h>
+#include <linux/poll.h>
+#include <linux/socket.h>
+#include <net/iucv/iucv.h>
+
+#ifndef AF_IUCV
+#define AF_IUCV		32
+#define PF_IUCV		AF_IUCV
+#endif
+
+/* Connection and socket states */
+enum {
+	IUCV_CONNECTED = 1,
+	IUCV_OPEN,
+	IUCV_BOUND,
+	IUCV_LISTEN,
+	IUCV_DISCONN,
+	IUCV_CLOSING,
+	IUCV_CLOSED
+};
+
+#define IUCV_QUEUELEN_DEFAULT	65535
+#define IUCV_HIPER_MSGLIM_DEFAULT	128
+#define IUCV_CONN_TIMEOUT	(HZ * 40)
+#define IUCV_DISCONN_TIMEOUT	(HZ * 2)
+#define IUCV_CONN_IDLE_TIMEOUT	(HZ * 60)
+#define IUCV_BUFSIZE_DEFAULT	32768
+
+/* IUCV socket address */
+struct sockaddr_iucv {
+	sa_family_t	siucv_family;
+	unsigned short	siucv_port;		/* Reserved */
+	unsigned int	siucv_addr;		/* Reserved */
+	char		siucv_nodeid[8];	/* Reserved */
+	char		siucv_user_id[8];	/* Guest User Id */
+	char		siucv_name[8];		/* Application Name */
+};
+
+
+/* Common socket structures and functions */
+struct sock_msg_q {
+	struct iucv_path	*path;
+	struct iucv_message	msg;
+	struct list_head	list;
+	spinlock_t		lock;
+};
+
+#define AF_IUCV_FLAG_ACK 0x1
+#define AF_IUCV_FLAG_SYN 0x2
+#define AF_IUCV_FLAG_FIN 0x4
+#define AF_IUCV_FLAG_WIN 0x8
+#define AF_IUCV_FLAG_SHT 0x10
+
+struct af_iucv_trans_hdr {
+	u16 magic;
+	u8 version;
+	u8 flags;
+	u16 window;
+	char destNodeID[8];
+	char destUserID[8];
+	char destAppName[16];
+	char srcNodeID[8];
+	char srcUserID[8];
+	char srcAppName[16];             /* => 70 bytes */
+	struct iucv_message iucv_hdr;    /* => 33 bytes */
+	u8 pad;                          /* total 104 bytes */
+} __packed;
+
+static inline struct af_iucv_trans_hdr *iucv_trans_hdr(struct sk_buff *skb)
+{
+	return (struct af_iucv_trans_hdr *)skb_network_header(skb);
+}
+
+enum iucv_tx_notify {
+	/* transmission of skb is completed and was successful */
+	TX_NOTIFY_OK = 0,
+	/* target is unreachable */
+	TX_NOTIFY_UNREACHABLE = 1,
+	/* transfer pending queue full */
+	TX_NOTIFY_TPQFULL = 2,
+	/* general error */
+	TX_NOTIFY_GENERALERROR = 3,
+	/* transmission of skb is pending - may interleave
+	 * with TX_NOTIFY_DELAYED_* */
+	TX_NOTIFY_PENDING = 4,
+	/* transmission of skb was done successfully (delayed) */
+	TX_NOTIFY_DELAYED_OK = 5,
+	/* target unreachable (detected delayed) */
+	TX_NOTIFY_DELAYED_UNREACHABLE = 6,
+	/* general error (detected delayed) */
+	TX_NOTIFY_DELAYED_GENERALERROR = 7,
+};
+
+#define iucv_sk(__sk) ((struct iucv_sock *) __sk)
+
+#define AF_IUCV_TRANS_IUCV 0
+#define AF_IUCV_TRANS_HIPER 1
+
+struct iucv_sock {
+	struct sock		sk;
+	struct_group(init,
+		char		src_user_id[8];
+		char		src_name[8];
+		char		dst_user_id[8];
+		char		dst_name[8];
+	);
+	struct list_head	accept_q;
+	spinlock_t		accept_q_lock;
+	struct sock		*parent;
+	struct iucv_path	*path;
+	struct net_device	*hs_dev;
+	struct sk_buff_head	send_skb_q;
+	struct sk_buff_head	backlog_skb_q;
+	struct sock_msg_q	message_q;
+	unsigned int		send_tag;
+	u8			flags;
+	u16			msglimit;
+	u16			msglimit_peer;
+	atomic_t		skbs_in_xmit;
+	atomic_t		msg_sent;
+	atomic_t		msg_recv;
+	atomic_t		pendings;
+	int			transport;
+	void			(*sk_txnotify)(struct sock *sk,
+					       enum iucv_tx_notify n);
+};
+
+struct iucv_skb_cb {
+	u32	class;		/* target class of message */
+	u32	tag;		/* tag associated with message */
+	u32	offset;		/* offset for skb receival */
+};
+
+#define IUCV_SKB_CB(__skb)	((struct iucv_skb_cb *)&((__skb)->cb[0]))
+
+/* iucv socket options (SOL_IUCV) */
+#define SO_IPRMDATA_MSG	0x0080		/* send/recv IPRM_DATA msgs */
+#define SO_MSGLIMIT	0x1000		/* get/set IUCV MSGLIMIT */
+#define SO_MSGSIZE	0x0800		/* get maximum msgsize */
+
+/* iucv related control messages (scm) */
+#define SCM_IUCV_TRGCLS	0x0001		/* target class control message */
+
+struct iucv_sock_list {
+	struct hlist_head head;
+	rwlock_t	  lock;
+	atomic_t	  autobind_name;
+};
+
+#endif /* __IUCV_H */
diff --git a/include/net/iucv/iucv.h b/include/net/iucv/iucv.h
new file mode 100644
index 000000000..18f511da9
--- /dev/null
+++ b/include/net/iucv/iucv.h
@@ -0,0 +1,301 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  drivers/s390/net/iucv.h
+ *    IUCV base support.
+ *
+ *  S390 version
+ *    Copyright 2000, 2006 IBM Corporation
+ *    Author(s):Alan Altmark (Alan_Altmark@us.ibm.com)
+ *		Xenia Tkatschow (xenia@us.ibm.com)
+ *    Rewritten for af_iucv:
+ *	Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *
+ *
+ * Functionality:
+ * To explore any of the IUCV functions, one must first register their
+ * program using iucv_register(). Once your program has successfully
+ * completed a register, it can exploit the other functions.
+ * For further reference on all IUCV functionality, refer to the
+ * CP Programming Services book, also available on the web thru
+ * www.vm.ibm.com/pubs, manual # SC24-6084
+ *
+ * Definition of Return Codes
+ * - All positive return codes including zero are reflected back
+ *   from CP. The definition of each return code can be found in
+ *   CP Programming Services book.
+ * - Return Code of:
+ *   -EINVAL: Invalid value
+ *   -ENOMEM: storage allocation failed
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <asm/dma-types.h>
+#include <asm/debug.h>
+
+/*
+ * IUCV option flags usable by device drivers:
+ *
+ * IUCV_IPRMDATA  Indicates that your program can handle a message in the
+ *		  parameter list / a message is sent in the parameter list.
+ *		  Used for iucv_path_accept, iucv_path_connect,
+ *		  iucv_message_reply, iucv_message_send, iucv_message_send2way.
+ * IUCV_IPQUSCE	  Indicates that you do not want to receive messages on this
+ *		  path until an iucv_path_resume is issued.
+ *		  Used for iucv_path_accept, iucv_path_connect.
+ * IUCV_IPBUFLST  Indicates that an address list is used for the message data.
+ *		  Used for iucv_message_receive, iucv_message_send,
+ *		  iucv_message_send2way.
+ * IUCV_IPPRTY	  Specifies that you want to send priority messages.
+ *		  Used for iucv_path_accept, iucv_path_connect,
+ *		  iucv_message_reply, iucv_message_send, iucv_message_send2way.
+ * IUCV_IPSYNC	  Indicates a synchronous send request.
+ *		  Used for iucv_message_send, iucv_message_send2way.
+ * IUCV_IPANSLST  Indicates that an address list is used for the reply data.
+ *		  Used for iucv_message_reply, iucv_message_send2way.
+ * IUCV_IPLOCAL	  Specifies that the communication partner has to be on the
+ *		  local system. If local is specified no target class can be
+ *		  specified.
+ *		  Used for iucv_path_connect.
+ *
+ * All flags are defined in the input field IPFLAGS1 of each function
+ * and can be found in CP Programming Services.
+ */
+#define IUCV_IPRMDATA	0x80
+#define IUCV_IPQUSCE	0x40
+#define IUCV_IPBUFLST	0x40
+#define IUCV_IPPRTY	0x20
+#define IUCV_IPANSLST	0x08
+#define IUCV_IPSYNC	0x04
+#define IUCV_IPLOCAL	0x01
+
+/*
+ * iucv_array : Defines buffer array.
+ * Inside the array may be 31- bit addresses and 31-bit lengths.
+ * Use a pointer to an iucv_array as the buffer, reply or answer
+ * parameter on iucv_message_send, iucv_message_send2way, iucv_message_receive
+ * and iucv_message_reply if IUCV_IPBUFLST or IUCV_IPANSLST are used.
+ */
+struct iucv_array {
+	dma32_t address;
+	u32 length;
+} __attribute__ ((aligned (8)));
+
+extern const struct bus_type iucv_bus;
+
+struct device_driver;
+
+struct device *iucv_alloc_device(const struct attribute_group **attrs,
+				 struct device_driver *driver, void *priv,
+				 const char *fmt, ...) __printf(4, 5);
+
+/*
+ * struct iucv_path
+ * pathid: 16 bit path identification
+ * msglim: 16 bit message limit
+ * flags: properties of the path: IPRMDATA, IPQUSCE, IPPRTY
+ * handler:  address of iucv handler structure
+ * private: private information of the handler associated with the path
+ * list: list_head for the iucv_handler path list.
+ */
+struct iucv_path {
+	u16 pathid;
+	u16 msglim;
+	u8  flags;
+	void *private;
+	struct iucv_handler *handler;
+	struct list_head list;
+};
+
+/*
+ * struct iucv_message
+ * id: 32 bit message id
+ * audit: 32 bit error information of purged or replied messages
+ * class: 32 bit target class of a message (source class for replies)
+ * tag: 32 bit tag to be associated with the message
+ * length: 32 bit length of the message / reply
+ * reply_size: 32 bit maximum allowed length of the reply
+ * rmmsg: 8 byte inline message
+ * flags: message properties (IUCV_IPPRTY)
+ */
+struct iucv_message {
+	u32 id;
+	u32 audit;
+	u32 class;
+	u32 tag;
+	u32 length;
+	u32 reply_size;
+	u8  rmmsg[8];
+	u8  flags;
+} __packed;
+
+/*
+ * struct iucv_handler
+ *
+ * A vector of functions that handle IUCV interrupts. Each functions gets
+ * a parameter area as defined by the CP Programming Services and private
+ * pointer that is provided by the user of the interface.
+ */
+struct iucv_handler {
+	 /*
+	  * The path_pending function is called after an iucv interrupt
+	  * type 0x01 has been received. The base code allocates a path
+	  * structure and "asks" the handler if this path belongs to the
+	  * handler. To accept the path the path_pending function needs
+	  * to call iucv_path_accept and return 0. If the callback returns
+	  * a value != 0 the iucv base code will continue with the next
+	  * handler. The order in which the path_pending functions are
+	  * called is the order of the registration of the iucv handlers
+	  * to the base code.
+	  */
+	int  (*path_pending)(struct iucv_path *, u8 *ipvmid, u8 *ipuser);
+	/*
+	 * The path_complete function is called after an iucv interrupt
+	 * type 0x02 has been received for a path that has been established
+	 * for this handler with iucv_path_connect and got accepted by the
+	 * peer with iucv_path_accept.
+	 */
+	void (*path_complete)(struct iucv_path *, u8 *ipuser);
+	 /*
+	  * The path_severed function is called after an iucv interrupt
+	  * type 0x03 has been received. The communication peer shutdown
+	  * his end of the communication path. The path still exists and
+	  * remaining messages can be received until a iucv_path_sever
+	  * shuts down the other end of the path as well.
+	  */
+	void (*path_severed)(struct iucv_path *, u8 *ipuser);
+	/*
+	 * The path_quiesced function is called after an icuv interrupt
+	 * type 0x04 has been received. The communication peer has quiesced
+	 * the path. Delivery of messages is stopped until iucv_path_resume
+	 * has been called.
+	 */
+	void (*path_quiesced)(struct iucv_path *, u8 *ipuser);
+	/*
+	 * The path_resumed function is called after an icuv interrupt
+	 * type 0x05 has been received. The communication peer has resumed
+	 * the path.
+	 */
+	void (*path_resumed)(struct iucv_path *, u8 *ipuser);
+	/*
+	 * The message_pending function is called after an icuv interrupt
+	 * type 0x06 or type 0x07 has been received. A new message is
+	 * available and can be received with iucv_message_receive.
+	 */
+	void (*message_pending)(struct iucv_path *, struct iucv_message *);
+	/*
+	 * The message_complete function is called after an icuv interrupt
+	 * type 0x08 or type 0x09 has been received. A message send with
+	 * iucv_message_send2way has been replied to. The reply can be
+	 * received with iucv_message_receive.
+	 */
+	void (*message_complete)(struct iucv_path *, struct iucv_message *);
+
+	struct list_head list;
+	struct list_head paths;
+};
+
+int iucv_register(struct iucv_handler *handler, int smp);
+void iucv_unregister(struct iucv_handler *handler, int smp);
+
+/**
+ * iucv_path_alloc - Allocate a new path structure for use with iucv_connect.
+ * @msglim: initial message limit
+ * @flags: initial flags
+ * @gfp: kmalloc allocation flag
+ *
+ * Returns: NULL if the memory allocation failed or a pointer to the
+ * path structure.
+ */
+static inline struct iucv_path *iucv_path_alloc(u16 msglim, u8 flags, gfp_t gfp)
+{
+	struct iucv_path *path;
+
+	path = kzalloc_obj(struct iucv_path, gfp);
+	if (path) {
+		path->msglim = msglim;
+		path->flags = flags;
+	}
+	return path;
+}
+
+/**
+ * iucv_path_free - Frees a path structure.
+ * @path: address of iucv path structure
+ */
+static inline void iucv_path_free(struct iucv_path *path)
+{
+	kfree(path);
+}
+
+int iucv_path_accept(struct iucv_path *path, struct iucv_handler *handler,
+		     u8 *userdata, void *private);
+
+int iucv_path_connect(struct iucv_path *path, struct iucv_handler *handler,
+		      u8 *userid, u8 *system, u8 *userdata,
+		      void *private);
+
+int iucv_path_quiesce(struct iucv_path *path, u8 *userdata);
+
+int iucv_path_resume(struct iucv_path *path, u8 *userdata);
+
+int iucv_path_sever(struct iucv_path *path, u8 *userdata);
+
+int iucv_message_purge(struct iucv_path *path, struct iucv_message *msg,
+		       u32 srccls);
+
+int iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
+			 u8 flags, void *buffer, size_t size, size_t *residual);
+
+int __iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
+			   u8 flags, void *buffer, size_t size,
+			   size_t *residual);
+
+int iucv_message_reject(struct iucv_path *path, struct iucv_message *msg);
+
+int iucv_message_reply(struct iucv_path *path, struct iucv_message *msg,
+		       u8 flags, void *reply, size_t size);
+
+int iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
+		      u8 flags, u32 srccls, void *buffer, size_t size);
+
+int __iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
+			u8 flags, u32 srccls, void *buffer, size_t size);
+
+int iucv_message_send2way(struct iucv_path *path, struct iucv_message *msg,
+			  u8 flags, u32 srccls, void *buffer, size_t size,
+			  void *answer, size_t asize, size_t *residual);
+
+struct iucv_interface {
+	int (*message_receive)(struct iucv_path *path, struct iucv_message *msg,
+		u8 flags, void *buffer, size_t size, size_t *residual);
+	int (*__message_receive)(struct iucv_path *path,
+		struct iucv_message *msg, u8 flags, void *buffer, size_t size,
+		size_t *residual);
+	int (*message_reply)(struct iucv_path *path, struct iucv_message *msg,
+		u8 flags, void *reply, size_t size);
+	int (*message_reject)(struct iucv_path *path, struct iucv_message *msg);
+	int (*message_send)(struct iucv_path *path, struct iucv_message *msg,
+		u8 flags, u32 srccls, void *buffer, size_t size);
+	int (*__message_send)(struct iucv_path *path, struct iucv_message *msg,
+		u8 flags, u32 srccls, void *buffer, size_t size);
+	int (*message_send2way)(struct iucv_path *path,
+		struct iucv_message *msg, u8 flags, u32 srccls, void *buffer,
+		size_t size, void *answer, size_t asize, size_t *residual);
+	int (*message_purge)(struct iucv_path *path, struct iucv_message *msg,
+		u32 srccls);
+	int (*path_accept)(struct iucv_path *path, struct iucv_handler *handler,
+		u8 userdata[16], void *private);
+	int (*path_connect)(struct iucv_path *path,
+		struct iucv_handler *handler,
+		u8 userid[8], u8 system[8], u8 userdata[16], void *private);
+	int (*path_quiesce)(struct iucv_path *path, u8 userdata[16]);
+	int (*path_resume)(struct iucv_path *path, u8 userdata[16]);
+	int (*path_sever)(struct iucv_path *path, u8 userdata[16]);
+	int (*iucv_register)(struct iucv_handler *handler, int smp);
+	void (*iucv_unregister)(struct iucv_handler *handler, int smp);
+	const struct bus_type *bus;
+	struct device *root;
+};
+
+extern struct iucv_interface iucv_if;