fs/smb/smbdirect/socket.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 *   Copyright (c) 2025 Stefan Metzmacher
 */

#ifndef __FS_SMB_COMMON_SMBDIRECT_SMBDIRECT_SOCKET_H__
#define __FS_SMB_COMMON_SMBDIRECT_SMBDIRECT_SOCKET_H__

#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/kref.h>
#include <linux/mempool.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/completion.h>
#include <rdma/rw.h>

enum smbdirect_socket_status {
	SMBDIRECT_SOCKET_CREATED,
	SMBDIRECT_SOCKET_LISTENING,
	SMBDIRECT_SOCKET_RESOLVE_ADDR_NEEDED,
	SMBDIRECT_SOCKET_RESOLVE_ADDR_RUNNING,
	SMBDIRECT_SOCKET_RESOLVE_ADDR_FAILED,
	SMBDIRECT_SOCKET_RESOLVE_ROUTE_NEEDED,
	SMBDIRECT_SOCKET_RESOLVE_ROUTE_RUNNING,
	SMBDIRECT_SOCKET_RESOLVE_ROUTE_FAILED,
	SMBDIRECT_SOCKET_RDMA_CONNECT_NEEDED,
	SMBDIRECT_SOCKET_RDMA_CONNECT_RUNNING,
	SMBDIRECT_SOCKET_RDMA_CONNECT_FAILED,
	SMBDIRECT_SOCKET_NEGOTIATE_NEEDED,
	SMBDIRECT_SOCKET_NEGOTIATE_RUNNING,
	SMBDIRECT_SOCKET_NEGOTIATE_FAILED,
	SMBDIRECT_SOCKET_CONNECTED,
	SMBDIRECT_SOCKET_ERROR,
	SMBDIRECT_SOCKET_DISCONNECTING,
	SMBDIRECT_SOCKET_DISCONNECTED,
	SMBDIRECT_SOCKET_DESTROYED
};

static __always_inline
const char *smbdirect_socket_status_string(enum smbdirect_socket_status status)
{
	switch (status) {
	case SMBDIRECT_SOCKET_CREATED:
		return "CREATED";
	case SMBDIRECT_SOCKET_LISTENING:
		return "LISTENING";
	case SMBDIRECT_SOCKET_RESOLVE_ADDR_NEEDED:
		return "RESOLVE_ADDR_NEEDED";
	case SMBDIRECT_SOCKET_RESOLVE_ADDR_RUNNING:
		return "RESOLVE_ADDR_RUNNING";
	case SMBDIRECT_SOCKET_RESOLVE_ADDR_FAILED:
		return "RESOLVE_ADDR_FAILED";
	case SMBDIRECT_SOCKET_RESOLVE_ROUTE_NEEDED:
		return "RESOLVE_ROUTE_NEEDED";
	case SMBDIRECT_SOCKET_RESOLVE_ROUTE_RUNNING:
		return "RESOLVE_ROUTE_RUNNING";
	case SMBDIRECT_SOCKET_RESOLVE_ROUTE_FAILED:
		return "RESOLVE_ROUTE_FAILED";
	case SMBDIRECT_SOCKET_RDMA_CONNECT_NEEDED:
		return "RDMA_CONNECT_NEEDED";
	case SMBDIRECT_SOCKET_RDMA_CONNECT_RUNNING:
		return "RDMA_CONNECT_RUNNING";
	case SMBDIRECT_SOCKET_RDMA_CONNECT_FAILED:
		return "RDMA_CONNECT_FAILED";
	case SMBDIRECT_SOCKET_NEGOTIATE_NEEDED:
		return "NEGOTIATE_NEEDED";
	case SMBDIRECT_SOCKET_NEGOTIATE_RUNNING:
		return "NEGOTIATE_RUNNING";
	case SMBDIRECT_SOCKET_NEGOTIATE_FAILED:
		return "NEGOTIATE_FAILED";
	case SMBDIRECT_SOCKET_CONNECTED:
		return "CONNECTED";
	case SMBDIRECT_SOCKET_ERROR:
		return "ERROR";
	case SMBDIRECT_SOCKET_DISCONNECTING:
		return "DISCONNECTING";
	case SMBDIRECT_SOCKET_DISCONNECTED:
		return "DISCONNECTED";
	case SMBDIRECT_SOCKET_DESTROYED:
		return "DESTROYED";
	}

	return "<unknown>";
}

/*
 * This can be used with %1pe to print errors as strings or '0'
 * And it avoids warnings like: warn: passing zero to 'ERR_PTR'
 * from smatch -p=kernel --pedantic
 */
static __always_inline
const void * __must_check SMBDIRECT_DEBUG_ERR_PTR(long error)
{
	if (error == 0)
		return NULL;
	return ERR_PTR(error);
}

enum smbdirect_keepalive_status {
	SMBDIRECT_KEEPALIVE_NONE,
	SMBDIRECT_KEEPALIVE_PENDING,
	SMBDIRECT_KEEPALIVE_SENT
};

struct smbdirect_socket {
	enum smbdirect_socket_status status;
	wait_queue_head_t status_wait;
	int first_error;

	/*
	 * This points to the workqueues to
	 * be used for this socket.
	 */
	struct {
		struct workqueue_struct *accept;
		struct workqueue_struct *connect;
		struct workqueue_struct *idle;
		struct workqueue_struct *refill;
		struct workqueue_struct *immediate;
		struct workqueue_struct *cleanup;
	} workqueues;

	struct work_struct disconnect_work;

	/*
	 * The reference counts.
	 */
	struct {
		/*
		 * This holds the references by the
		 * frontend, typically the smb layer.
		 *
		 * It is typically 1 and a disconnect
		 * will happen if it reaches 0.
		 */
		struct kref disconnect;

		/*
		 * This holds the reference by the
		 * backend, the code that manages
		 * the lifetime of the whole
		 * struct smbdirect_socket,
		 * if this reaches 0 it can will
		 * be freed.
		 *
		 * Can be REFCOUNT_MAX is part
		 * of another structure.
		 *
		 * This is equal or higher than
		 * the disconnect refcount.
		 */
		struct kref destroy;
	} refs;

	/* RDMA related */
	struct {
		struct rdma_cm_id *cm_id;
		/*
		 * The expected event in our current
		 * cm_id->event_handler, all other events
		 * are treated as an error.
		 */
		enum rdma_cm_event_type expected_event;
		/*
		 * This is for iWarp MPA v1
		 */
		bool legacy_iwarp;
	} rdma;

	/* IB verbs related */
	struct {
		struct ib_pd *pd;
		enum ib_poll_context poll_ctx;
		struct ib_cq *send_cq;
		struct ib_cq *recv_cq;

		/*
		 * shortcuts for rdma.cm_id->{qp,device};
		 */
		struct ib_qp *qp;
		struct ib_device *dev;
	} ib;

	struct smbdirect_socket_parameters parameters;

	/*
	 * The state for connect/negotiation
	 */
	struct {
		spinlock_t lock;
		struct work_struct work;
	} connect;

	/*
	 * The state for keepalive and timeout handling
	 */
	struct {
		enum smbdirect_keepalive_status keepalive;
		struct work_struct immediate_work;
		struct delayed_work timer_work;
	} idle;

	/*
	 * The state for listen sockets
	 */
	struct {
		spinlock_t lock;
		struct list_head pending;
		struct list_head ready;
		wait_queue_head_t wait_queue;
		/*
		 * This starts as -1 and a value != -1
		 * means this socket was in LISTENING state
		 * before. Note the valid backlog can
		 * only be > 0.
		 */
		int backlog;
	} listen;

	/*
	 * The state for sockets waiting
	 * for accept, either still waiting
	 * for the negotiation to finish
	 * or already ready with a usable
	 * connection.
	 */
	struct {
		struct smbdirect_socket *listener;
		struct list_head list;
	} accept;

	/*
	 * The state for posted send buffers
	 */
	struct {
		/*
		 * Memory pools for preallocating
		 * smbdirect_send_io buffers
		 */
		struct {
			struct kmem_cache *cache;
			mempool_t *pool;
			gfp_t gfp_mask;
		} mem;

		/*
		 * This is a coordination for smbdirect_send_batch.
		 *
		 * There's only one possible credit, which means
		 * only one instance is running at a time.
		 */
		struct {
			atomic_t count;
			wait_queue_head_t wait_queue;
		} bcredits;

		/*
		 * The local credit state for ib_post_send()
		 */
		struct {
			atomic_t count;
			wait_queue_head_t wait_queue;
		} lcredits;

		/*
		 * The remote credit state for the send side
		 */
		struct {
			atomic_t count;
			wait_queue_head_t wait_queue;
		} credits;

		/*
		 * The state about posted/pending sends
		 */
		struct {
			atomic_t count;
			/*
			 * woken when count reached zero
			 */
			wait_queue_head_t zero_wait_queue;
		} pending;
	} send_io;

	/*
	 * The state for posted receive buffers
	 */
	struct {
		/*
		 * The type of PDU we are expecting
		 */
		enum {
			SMBDIRECT_EXPECT_NEGOTIATE_REQ = 1,
			SMBDIRECT_EXPECT_NEGOTIATE_REP = 2,
			SMBDIRECT_EXPECT_DATA_TRANSFER = 3,
		} expected;

		/*
		 * Memory pools for preallocating
		 * smbdirect_recv_io buffers
		 */
		struct {
			struct kmem_cache *cache;
			mempool_t *pool;
			gfp_t gfp_mask;
		} mem;

		/*
		 * The list of free smbdirect_recv_io
		 * structures
		 */
		struct {
			struct list_head list;
			spinlock_t lock;
		} free;

		/*
		 * The state for posted recv_io messages
		 * and the refill work struct.
		 */
		struct {
			atomic_t count;
			struct work_struct refill_work;
		} posted;

		/*
		 * The credit state for the recv side
		 */
		struct {
			u16 target;
			atomic_t available;
			atomic_t count;
		} credits;

		/*
		 * The list of arrived non-empty smbdirect_recv_io
		 * structures
		 *
		 * This represents the reassembly queue.
		 */
		struct {
			struct list_head list;
			spinlock_t lock;
			wait_queue_head_t wait_queue;
			/* total data length of reassembly queue */
			int data_length;
			int queue_length;
			/* the offset to first buffer in reassembly queue */
			int first_entry_offset;
			/*
			 * Indicate if we have received a full packet on the
			 * connection This is used to identify the first SMBD
			 * packet of a assembled payload (SMB packet) in
			 * reassembly queue so we can return a RFC1002 length to
			 * upper layer to indicate the length of the SMB packet
			 * received
			 */
			bool full_packet_received;
		} reassembly;
	} recv_io;

	/*
	 * The state for Memory registrations on the client
	 */
	struct {
		enum ib_mr_type type;

		/*
		 * The list of free smbdirect_mr_io
		 * structures
		 */
		struct {
			struct list_head list;
			spinlock_t lock;
		} all;

		/*
		 * The number of available MRs ready for memory registration
		 */
		struct {
			atomic_t count;
			wait_queue_head_t wait_queue;
		} ready;

		/*
		 * The number of used MRs
		 */
		struct {
			atomic_t count;
		} used;
	} mr_io;

	/*
	 * The state for RDMA read/write requests on the server
	 */
	struct {
		/*
		 * Memory hints for
		 * smbdirect_rw_io structs
		 */
		struct {
			gfp_t gfp_mask;
		} mem;

		/*
		 * The credit state for the send side
		 */
		struct {
			/*
			 * The maximum number of rw credits
			 */
			size_t max;
			/*
			 * The number of pages per credit
			 */
			size_t num_pages;
			atomic_t count;
			wait_queue_head_t wait_queue;
		} credits;
	} rw_io;

	/*
	 * For debug purposes
	 */
	struct {
		u64 get_receive_buffer;
		u64 put_receive_buffer;
		u64 enqueue_reassembly_queue;
		u64 dequeue_reassembly_queue;
		u64 send_empty;
	} statistics;

	struct {
		void *private_ptr;
		bool (*needed)(struct smbdirect_socket *sc,
			       void *private_ptr,
			       unsigned int lvl,
			       unsigned int cls);
		void (*vaprintf)(struct smbdirect_socket *sc,
				 const char *func,
				 unsigned int line,
				 void *private_ptr,
				 unsigned int lvl,
				 unsigned int cls,
				 struct va_format *vaf);
	} logging;
};

static void __smbdirect_socket_disabled_work(struct work_struct *work)
{
	/*
	 * Should never be called as disable_[delayed_]work_sync() was used.
	 */
	WARN_ON_ONCE(1);
}

static bool __smbdirect_log_needed(struct smbdirect_socket *sc,
				   void *private_ptr,
				   unsigned int lvl,
				   unsigned int cls)
{
	/*
	 * Should never be called, the caller should
	 * set it's own functions.
	 */
	WARN_ON_ONCE(1);
	return false;
}

static void __smbdirect_log_vaprintf(struct smbdirect_socket *sc,
				     const char *func,
				     unsigned int line,
				     void *private_ptr,
				     unsigned int lvl,
				     unsigned int cls,
				     struct va_format *vaf)
{
	/*
	 * Should never be called, the caller should
	 * set it's own functions.
	 */
	WARN_ON_ONCE(1);
}

__printf(6, 7)
static void __smbdirect_log_printf(struct smbdirect_socket *sc,
				   const char *func,
				   unsigned int line,
				   unsigned int lvl,
				   unsigned int cls,
				   const char *fmt,
				   ...);
__maybe_unused
static void __smbdirect_log_printf(struct smbdirect_socket *sc,
				   const char *func,
				   unsigned int line,
				   unsigned int lvl,
				   unsigned int cls,
				   const char *fmt,
				   ...)
{
	struct va_format vaf;
	va_list args;

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	sc->logging.vaprintf(sc,
			     func,
			     line,
			     sc->logging.private_ptr,
			     lvl,
			     cls,
			     &vaf);
	va_end(args);
}

#define ___smbdirect_log_generic(sc, func, line, lvl, cls, fmt, args...) do {	\
	if (sc->logging.needed(sc, sc->logging.private_ptr, lvl, cls)) {	\
		__smbdirect_log_printf(sc, func, line, lvl, cls, fmt, ##args);	\
	}									\
} while (0)
#define __smbdirect_log_generic(sc, lvl, cls, fmt, args...) \
	___smbdirect_log_generic(sc, __func__, __LINE__, lvl, cls, fmt, ##args)

#define smbdirect_log_outgoing(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_OUTGOING, fmt, ##args)
#define smbdirect_log_incoming(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_INCOMING, fmt, ##args)
#define smbdirect_log_read(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_READ, fmt, ##args)
#define smbdirect_log_write(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_WRITE, fmt, ##args)
#define smbdirect_log_rdma_send(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_RDMA_SEND, fmt, ##args)
#define smbdirect_log_rdma_recv(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_RDMA_RECV, fmt, ##args)
#define smbdirect_log_keep_alive(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_KEEP_ALIVE, fmt, ##args)
#define smbdirect_log_rdma_event(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_RDMA_EVENT, fmt, ##args)
#define smbdirect_log_rdma_mr(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_RDMA_MR, fmt, ##args)
#define smbdirect_log_rdma_rw(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_RDMA_RW, fmt, ##args)
#define smbdirect_log_negotiate(sc, lvl, fmt, args...) \
		__smbdirect_log_generic(sc, lvl, SMBDIRECT_LOG_NEGOTIATE, fmt, ##args)

static __always_inline void smbdirect_socket_init(struct smbdirect_socket *sc)
{
	/*
	 * This also sets status = SMBDIRECT_SOCKET_CREATED
	 */
	BUILD_BUG_ON(SMBDIRECT_SOCKET_CREATED != 0);
	memset(sc, 0, sizeof(*sc));

	init_waitqueue_head(&sc->status_wait);

	sc->workqueues.accept = smbdirect_globals.workqueues.accept;
	sc->workqueues.connect = smbdirect_globals.workqueues.connect;
	sc->workqueues.idle = smbdirect_globals.workqueues.idle;
	sc->workqueues.refill = smbdirect_globals.workqueues.refill;
	sc->workqueues.immediate = smbdirect_globals.workqueues.immediate;
	sc->workqueues.cleanup = smbdirect_globals.workqueues.cleanup;

	INIT_WORK(&sc->disconnect_work, __smbdirect_socket_disabled_work);
	disable_work_sync(&sc->disconnect_work);

	kref_init(&sc->refs.disconnect);
	sc->refs.destroy = (struct kref) KREF_INIT(REFCOUNT_MAX);

	sc->rdma.expected_event = RDMA_CM_EVENT_INTERNAL;

	sc->ib.poll_ctx = IB_POLL_UNBOUND_WORKQUEUE;

	spin_lock_init(&sc->connect.lock);
	INIT_WORK(&sc->connect.work, __smbdirect_socket_disabled_work);
	disable_work_sync(&sc->connect.work);

	INIT_WORK(&sc->idle.immediate_work, __smbdirect_socket_disabled_work);
	disable_work_sync(&sc->idle.immediate_work);
	INIT_DELAYED_WORK(&sc->idle.timer_work, __smbdirect_socket_disabled_work);
	disable_delayed_work_sync(&sc->idle.timer_work);

	spin_lock_init(&sc->listen.lock);
	INIT_LIST_HEAD(&sc->listen.pending);
	INIT_LIST_HEAD(&sc->listen.ready);
	sc->listen.backlog = -1; /* not a listener */
	init_waitqueue_head(&sc->listen.wait_queue);

	INIT_LIST_HEAD(&sc->accept.list);

	sc->send_io.mem.gfp_mask = GFP_KERNEL;

	atomic_set(&sc->send_io.bcredits.count, 0);
	init_waitqueue_head(&sc->send_io.bcredits.wait_queue);

	atomic_set(&sc->send_io.lcredits.count, 0);
	init_waitqueue_head(&sc->send_io.lcredits.wait_queue);

	atomic_set(&sc->send_io.credits.count, 0);
	init_waitqueue_head(&sc->send_io.credits.wait_queue);

	atomic_set(&sc->send_io.pending.count, 0);
	init_waitqueue_head(&sc->send_io.pending.zero_wait_queue);

	sc->recv_io.mem.gfp_mask = GFP_KERNEL;

	INIT_LIST_HEAD(&sc->recv_io.free.list);
	spin_lock_init(&sc->recv_io.free.lock);

	atomic_set(&sc->recv_io.posted.count, 0);
	INIT_WORK(&sc->recv_io.posted.refill_work, __smbdirect_socket_disabled_work);
	disable_work_sync(&sc->recv_io.posted.refill_work);

	atomic_set(&sc->recv_io.credits.available, 0);
	atomic_set(&sc->recv_io.credits.count, 0);

	INIT_LIST_HEAD(&sc->recv_io.reassembly.list);
	spin_lock_init(&sc->recv_io.reassembly.lock);
	init_waitqueue_head(&sc->recv_io.reassembly.wait_queue);

	sc->rw_io.mem.gfp_mask = GFP_KERNEL;
	atomic_set(&sc->rw_io.credits.count, 0);
	init_waitqueue_head(&sc->rw_io.credits.wait_queue);

	spin_lock_init(&sc->mr_io.all.lock);
	INIT_LIST_HEAD(&sc->mr_io.all.list);
	atomic_set(&sc->mr_io.ready.count, 0);
	init_waitqueue_head(&sc->mr_io.ready.wait_queue);
	atomic_set(&sc->mr_io.used.count, 0);

	sc->logging.private_ptr = NULL;
	sc->logging.needed = __smbdirect_log_needed;
	sc->logging.vaprintf = __smbdirect_log_vaprintf;
}

#define __SMBDIRECT_CHECK_STATUS_FAILED(__sc, __expected_status, __error_cmd, __unexpected_cmd) ({ \
	bool __failed = false; \
	if (unlikely((__sc)->first_error)) { \
		__failed = true; \
		__error_cmd \
	} else if (unlikely((__sc)->status != (__expected_status))) { \
		__failed = true; \
		__unexpected_cmd \
	} \
	__failed; \
})

#define __SMBDIRECT_CHECK_STATUS_WARN(__sc, __expected_status, __unexpected_cmd) \
	__SMBDIRECT_CHECK_STATUS_FAILED(__sc, __expected_status, \
	{ \
		const struct sockaddr_storage *__src = NULL; \
		const struct sockaddr_storage *__dst = NULL; \
		if ((__sc)->rdma.cm_id) { \
			__src = &(__sc)->rdma.cm_id->route.addr.src_addr; \
			__dst = &(__sc)->rdma.cm_id->route.addr.dst_addr; \
		} \
		smbdirect_log_rdma_event(sc, SMBDIRECT_LOG_INFO, \
			"expected[%s] != %s first_error=%1pe local=%pISpsfc remote=%pISpsfc\n", \
			smbdirect_socket_status_string(__expected_status), \
			smbdirect_socket_status_string((__sc)->status), \
			SMBDIRECT_DEBUG_ERR_PTR((__sc)->first_error), \
			__src, __dst); \
	}, \
	{ \
		const struct sockaddr_storage *__src = NULL; \
		const struct sockaddr_storage *__dst = NULL; \
		if ((__sc)->rdma.cm_id) { \
			__src = &(__sc)->rdma.cm_id->route.addr.src_addr; \
			__dst = &(__sc)->rdma.cm_id->route.addr.dst_addr; \
		} \
		smbdirect_log_rdma_event(sc, SMBDIRECT_LOG_ERR, \
			"expected[%s] != %s first_error=%1pe local=%pISpsfc remote=%pISpsfc\n", \
			smbdirect_socket_status_string(__expected_status), \
			smbdirect_socket_status_string((__sc)->status), \
			SMBDIRECT_DEBUG_ERR_PTR((__sc)->first_error), \
			__src, __dst); \
		WARN_ONCE(1, \
			"expected[%s] != %s first_error=%1pe local=%pISpsfc remote=%pISpsfc\n", \
			smbdirect_socket_status_string(__expected_status), \
			smbdirect_socket_status_string((__sc)->status), \
			SMBDIRECT_DEBUG_ERR_PTR((__sc)->first_error), \
			__src, __dst); \
		__unexpected_cmd \
	})

#define SMBDIRECT_CHECK_STATUS_WARN(__sc, __expected_status) \
	__SMBDIRECT_CHECK_STATUS_WARN(__sc, __expected_status, /* nothing */)

#ifndef __SMBDIRECT_SOCKET_DISCONNECT
#define __SMBDIRECT_SOCKET_DISCONNECT(__sc) \
		smbdirect_socket_schedule_cleanup(__sc, -ECONNABORTED)
#endif /* ! __SMBDIRECT_SOCKET_DISCONNECT */

#define SMBDIRECT_CHECK_STATUS_DISCONNECT(__sc, __expected_status) \
	__SMBDIRECT_CHECK_STATUS_WARN(__sc, __expected_status, \
		__SMBDIRECT_SOCKET_DISCONNECT(__sc);)

struct smbdirect_send_io {
	struct smbdirect_socket *socket;
	struct ib_cqe cqe;

	/*
	 * The SGE entries for this work request
	 *
	 * The first points to the packet header
	 */
#define SMBDIRECT_SEND_IO_MAX_SGE 6
	size_t num_sge;
	struct ib_sge sge[SMBDIRECT_SEND_IO_MAX_SGE];

	/*
	 * Link to the list of sibling smbdirect_send_io
	 * messages.
	 */
	struct list_head sibling_list;
	struct ib_send_wr wr;

	/* SMBD packet header follows this structure */
	u8 packet[];
};

struct smbdirect_send_batch {
	/*
	 * List of smbdirect_send_io messages
	 */
	struct list_head msg_list;
	/*
	 * Number of list entries
	 */
	size_t wr_cnt;

	/*
	 * Possible remote key invalidation state
	 */
	bool need_invalidate_rkey;
	u32 remote_key;

	int credit;
};

struct smbdirect_recv_io {
	struct smbdirect_socket *socket;
	struct ib_cqe cqe;

	/*
	 * For now we only use a single SGE
	 * as we have just one large buffer
	 * per posted recv.
	 */
#define SMBDIRECT_RECV_IO_MAX_SGE 1
	struct ib_sge sge;

	/* Link to free or reassembly list */
	struct list_head list;

	/* Indicate if this is the 1st packet of a payload */
	bool first_segment;

	/* SMBD packet header and payload follows this structure */
	u8 packet[];
};

enum smbdirect_mr_state {
	SMBDIRECT_MR_READY,
	SMBDIRECT_MR_REGISTERED,
	SMBDIRECT_MR_INVALIDATED,
	SMBDIRECT_MR_ERROR,
	SMBDIRECT_MR_DISABLED
};

struct smbdirect_mr_io {
	struct smbdirect_socket *socket;
	struct ib_cqe cqe;

	/*
	 * We can have up to two references:
	 * 1. by the connection
	 * 2. by the registration
	 */
	struct kref kref;
	struct mutex mutex;

	struct list_head list;

	enum smbdirect_mr_state state;
	struct ib_mr *mr;
	struct sg_table sgt;
	enum dma_data_direction dir;
	union {
		struct ib_reg_wr wr;
		struct ib_send_wr inv_wr;
	};

	bool need_invalidate;
	struct completion invalidate_done;
};

struct smbdirect_rw_io {
	struct smbdirect_socket *socket;
	struct ib_cqe cqe;

	struct list_head list;

	int error;
	struct completion *completion;

	struct rdma_rw_ctx rdma_ctx;
	struct sg_table sgt;
	struct scatterlist sg_list[];
};

static inline size_t smbdirect_get_buf_page_count(const void *buf, size_t size)
{
	return DIV_ROUND_UP((uintptr_t)buf + size, PAGE_SIZE) -
		(uintptr_t)buf / PAGE_SIZE;
}

/*
 * Maximum number of retries on data transfer operations
 */
#define SMBDIRECT_RDMA_CM_RETRY 6
/*
 * No need to retry on Receiver Not Ready since SMB_DIRECT manages credits
 */
#define SMBDIRECT_RDMA_CM_RNR_RETRY 0

#endif /* __FS_SMB_COMMON_SMBDIRECT_SMBDIRECT_SOCKET_H__ */