#ifndef _RDS_RDS_H
#define _RDS_RDS_H
#include <net/sock.h>
#include <linux/scatterlist.h>
#include <linux/highmem.h>
#include <rdma/rdma_cm.h>
#include <linux/mutex.h>
#include <linux/rds.h>
#include "info.h"
/*
* RDS Network protocol version
*/
#define RDS_PROTOCOL_3_0 0x0300
#define RDS_PROTOCOL_3_1 0x0301
#define RDS_PROTOCOL_VERSION RDS_PROTOCOL_3_1
#define RDS_PROTOCOL_MAJOR(v) ((v) >> 8)
#define RDS_PROTOCOL_MINOR(v) ((v) & 255)
#define RDS_PROTOCOL(maj, min) (((maj) << 8) | min)
/*
* XXX randomly chosen, but at least seems to be unused:
* # 18464-18768 Unassigned
* We should do better. We want a reserved port to discourage unpriv'ed
* userspace from listening.
*/
#define RDS_PORT 18634
#ifdef ATOMIC64_INIT
#define KERNEL_HAS_ATOMIC64
#endif
#ifdef DEBUG
#define rdsdebug(fmt, args...) pr_debug("%s(): " fmt, __func__ , ##args)
#else
/* sigh, pr_debug() causes unused variable warnings */
static inline void __attribute__ ((format (printf, 1, 2)))
rdsdebug(char *fmt, ...)
{
}
#endif
/* XXX is there one of these somewhere? */
#define ceil(x, y) \
({ unsigned long __x = (x), __y = (y); (__x + __y - 1) / __y; })
#define RDS_FRAG_SHIFT 12
#define RDS_FRAG_SIZE ((unsigned int)(1 << RDS_FRAG_SHIFT))
#define RDS_CONG_MAP_BYTES (65536 / 8)
#define RDS_CONG_MAP_LONGS (RDS_CONG_MAP_BYTES / sizeof(unsigned long))
#define RDS_CONG_MAP_PAGES (PAGE_ALIGN(RDS_CONG_MAP_BYTES) / PAGE_SIZE)
#define RDS_CONG_MAP_PAGE_BITS (PAGE_SIZE * 8)
struct rds_cong_map {
struct rb_node m_rb_node;
__be32 m_addr;
wait_queue_head_t m_waitq;
struct list_head m_conn_list;
unsigned long m_page_addrs[RDS_CONG_MAP_PAGES];
};
/*
* This is how we will track the connection state:
* A connection is always in one of the following
* states. Updates to the state are atomic and imply
* a memory barrier.
*/
enum {
RDS_CONN_DOWN = 0,
RDS_CONN_CONNECTING,
RDS_CONN_DISCONNECTING,
RDS_CONN_UP,
RDS_CONN_ERROR,
};
/* Bits for c_flags */
#define RDS_LL_SEND_FULL 0
#define RDS_RECONNECT_PENDING 1
struct rds_connection {
struct hlist_node c_hash_node;
__be32 c_laddr;
__be32 c_faddr;
unsigned int c_loopback:1;
struct rds_connection *c_passive;
struct rds_cong_map *c_lcong;
struct rds_cong_map *c_fcong;
struct mutex c_send_lock; /* protect send ring */
struct rds_message *c_xmit_rm;
unsigned long c_xmit_sg;
unsigned int c_xmit_hdr_off;
unsigned int c_xmit_data_off;
unsigned int c_xmit_rdma_sent;
spinlock_t c_lock; /* protect msg queues */
u64 c_next_tx_seq;
struct list_head c_send_queue;
struct list_head c_retrans;
u64 c_next_rx_seq;
struct rds_transport *c_trans;
void *c_transport_data;
atomic_t c_state;
unsigned long c_flags;
unsigned long c_reconnect_jiffies;
struct delayed_work c_send_w;
struct delayed_work c_recv_w;
struct delayed_work c_conn_w;
struct work_struct c_down_w;
struct mutex c_cm_lock; /* protect conn state & cm */
struct list_head c_map_item;
unsigned long c_map_queued;
unsigned long c_map_offset;
unsigned long c_map_bytes;
unsigned int c_unacked_packets;
unsigned int c_unacked_bytes;
/* Protocol version */
unsigned int c_version;
};
#define RDS_FLAG_CONG_BITMAP 0x01
#define RDS_FLAG_ACK_REQUIRED 0x02
#define RDS_FLAG_RETRANSMITTED 0x04
#define RDS_MAX_ADV_CREDIT 255
/*
* Maximum space available for extension headers.
*/
#define RDS_HEADER_EXT_SPACE 16
struct rds_header {
__be64 h_sequence;
__be64 h_ack;
__be32 h_len;
__be16 h_sport;
__be16 h_dport;
u8 h_flags;
u8 h_credit;
u8 h_padding[4];
__sum16 h_csum;
u8 h_exthdr[RDS_HEADER_EXT_SPACE];
};
/*
* Reserved - indicates end of extensions
*/
#define RDS_EXTHDR_NONE 0
/*
* This extension header is included in the very
* first message that is sent on a new connection,
* and identifies the protocol level. This will help
* rolling updates if a future change requires breaking
* the protocol.
* NB: This is no longer true for IB, where we do a version
* negotiation during the connection setup phase (protocol
* version information is included in the RDMA CM private data).
*/
#define RDS_EXTHDR_VERSION 1
struct rds_ext_header_version {
__be32 h_version;
};
/*
* This extension header is included in the RDS message
* chasing an RDMA operation.
*/
#define RDS_EXTHDR_RDMA 2
struct rds_ext_header_rdma {
__be32 h_rdma_rkey;
};
/*
* This extension header tells the peer about the
* destination <R_Key,offset> of the requested RDMA
* operation.
*/
#define RDS_EXTHDR_RDMA_DEST 3
struct rds_ext_header_rdma_dest {
__be32 h_rdma_rkey;
__be32 h_rdma_offset;
};
#define __RDS_EXTHDR_MAX 16 /* for now */
struct rds_incoming {
atomic_t i_refcount;
struct list_head i_item;
struct rds_connection *i_conn;
struct rds_header i_hdr;
unsigned long i_rx_jiffies;
__be32 i_saddr;
rds_rdma_cookie_t i_rdma_cookie;
};
/*
* m_sock_item and m_conn_item are on lists that are serialized under
* conn->c_lock. m_sock_item has additional meaning in that once it is empty
* the message will not be put back on the retransmit list after being sent.
* messages that are canceled while being sent rely on this.
*
* m_inc is used by loopback so that it can pass an incoming message straight
* back up into the rx path. It embeds a wire header which is also used by
* the send path, which is kind of awkward.
*
* m_sock_item indicates the message's presence on a socket's send or receive
* queue. m_rs will point to that socket.
*
* m_daddr is used by cancellation to prune messages to a given destination.
*
* The RDS_MSG_ON_SOCK and RDS_MSG_ON_CONN flags are used to avoid lock
* nesting. As paths iterate over messages on a sock, or conn, they must
* also lock the conn, or sock, to remove the message from those lists too.
* Testing the flag to determine if the message is still on the lists lets
* us avoid testing the list_head directly. That means each path can use
* the message's list_head to keep it on a local list while juggling locks
* without confusing the other path.
*
* m_ack_seq is an optional field set by transports who need a different
* sequence number range to invalidate. They can use this in a callback
* that they pass to rds_send_drop_acked() to see if each message has been
* acked. The HAS_ACK_SEQ flag can be used to detect messages which haven't
* had ack_seq set yet.
*/
#define RDS_MSG_ON_SOCK 1
#define RDS_MSG_ON_CONN 2
#define RDS_MSG_HAS_ACK_SEQ 3
#define RDS_MSG_ACK_REQUIRED 4
#define RDS_MSG_RETRANSMITTED 5
#define RDS_MSG_MAPPED 6
#define RDS_MSG_PAGEVEC 7
struct rds_message {
atomic_t m_refcount;
struct list_head m_sock_item;
struct list_head m_conn_item;
struct rds_incoming m_inc;
u64 m_ack_seq;
__be32 m_daddr;
unsigned long m_flags;
/* Never access m_rs without holding m_rs_lock.
* Lock nesting is
* rm->m_rs_lock
* -> rs->rs_lock
*/
spinlock_t m_rs_lock;
struct rds_sock *m_rs;
struct rds_rdma_op *m_rdma_op;
rds_rdma_cookie_t m_rdma_cookie;
struct rds_mr *m_rdma_mr;
unsigned int m_nents;
unsigned int m_count;
struct scatterlist m_sg[0];
};
/*
* The RDS notifier is used (optionally) to tell the application about
* completed RDMA operations. Rather than keeping the whole rds message
* around on the queue, we allocate a small notifier that is put on the
* socket's notifier_list. Notifications are delivered to the application
* through control messages.
*/
struct rds_notifier {
struct list_head n_list;
uint64_t n_user_token;
int n_status;
};
/**
* struct rds_transport - transport specific behavioural hooks
*
* @xmit: .xmit is called by rds_send_xmit() to tell the transport to send
* part of a message. The caller serializes on the send_sem so this
* doesn't need to be reentrant for a given conn. The header must be
* sent before the data payload. .xmit must be prepared to send a
* message with no data payload. .xmit should return the number of
* bytes that were sent down the connection, including header bytes.
* Returning 0 tells the caller that it doesn't need to perform any
* additional work now. This is usually the case when the transport has
* filled the sending queue for its connection and will handle
* triggering the rds thread to continue the send when space becomes
* available. Returning -EAGAIN tells the caller to retry the send
* immediately. Returning -ENOMEM tells the caller to retry the send at
* some point in the future.
*
* @conn_shutdown: conn_shutdown stops traffic on the given connection. Once
* it returns the connection can not call rds_recv_incoming().
* This will only be called once after conn_connect returns
* non-zero success and will The caller serializes this with
* the send and connecting paths (xmit_* and conn_*). The
* transport is responsible for other serialization, including
* rds_recv_incoming(). This is called in process context but
* should try hard not to block.
*
* @xmit_cong_map: This asks the transport to send the local bitmap down the
* given connection. XXX get a better story about the bitmap
* flag and header.
*/
#define RDS_TRANS_IB 0
#define RDS_TRANS_IWARP 1
#define RDS_TRANS_TCP 2
#define RDS_TRANS_COUNT 3
struct rds_transport {
char t_name[TRANSNAMSIZ];
struct list_head t_item;
struct module *t_owner;
unsigned int t_prefer_loopback:1;
unsigned int t_type;
int (*laddr_check)(__be32 addr);
int (*conn_alloc)(struct rds_connection *conn, gfp_t gfp);
void (*conn_free)(void *data);
int (*conn_connect)(struct rds_connection *conn);
void (*conn_shutdown)(struct rds_connection *conn);
void (*xmit_prepare)(struct rds_connection *conn);
void (*xmit_complete)(struct rds_connection *conn);
int (*xmit)(struct rds_connection *conn, struct rds_message *rm,
unsigned int hdr_off, unsigned int sg, unsigned int off);
int (*xmit_cong_map)(struct rds_connection *conn,
struct rds_cong_map *map, unsigned long offset);
int (*xmit_rdma)(struct rds_connection *conn, struct rds_rdma_op *op);
int (*recv)(struct rds_connection *conn);
int (*inc_copy_to_user)(struct rds_incoming *inc, struct iovec *iov,
size_t size);
void (*inc_purge)(struct rds_incoming *inc);
void (*inc_free)(struct rds_incoming *inc);
int (*cm_handle_connect)(struct rdma_cm_id *cm_id,
struct rdma_cm_event *event);
int (*cm_initiate_connect)(struct rdma_cm_id *cm_id);
void (*cm_connect_complete)(struct rds_connection *conn,
struct rdma_cm_event *event);
unsigned int (*stats_info_copy)(struct rds_info_iterator *iter,
unsigned int avail);
void (*exit)(void);
void *(*get_mr)(struct scatterlist *sg, unsigned long nr_sg,
struct rds_sock *rs, u32 *key_ret);
void (*sync_mr)(void *trans_private, int direction);
void (*free_mr)(void *trans_private, int invalidate);
void (*flush_mrs)(void);
};
struct rds_sock {
struct sock rs_sk;
u64 rs_user_addr;
u64 rs_user_bytes;
/*
* bound_addr used for both incoming and outgoing, no INADDR_ANY
* support.
*/
struct rb_node rs_bound_node;
__be32 rs_bound_addr;
__be32 rs_conn_addr;
__be16 rs_bound_port;
__be16 rs_conn_port;
/*
* This is only used to communicate the transport between bind and
* initiating connections. All other trans use is referenced through
* the connection.
*/
struct rds_transport *rs_transport;
/*
* rds_sendmsg caches the conn it used the last time around.
* This helps avoid costly lookups.
*/
struct rds_connection *rs_conn;
/* flag indicating we were congested or not */
int rs_congested;
/* rs_lock protects all these adjacent members before the newline */
spinlock_t rs_lock;
struct list_head rs_send_queue;
u32 rs_snd_bytes;
int rs_rcv_bytes;
struct list_head rs_notify_queue; /* currently used for failed RDMAs */
/* Congestion wake_up. If rs_cong_monitor is set, we use cong_mask
* to decide whether the application should be woken up.
* If not set, we use rs_cong_track to find out whether a cong map
* update arrived.
*/
uint64_t rs_cong_mask;
uint64_t rs_cong_notify;
struct list_head rs_cong_list;
unsigned long rs_cong_track;
/*
* rs_recv_lock protects the receive queue, and is
* used to serialize with rds_release.
*/
rwlock_t rs_recv_lock;
struct list_head rs_recv_queue;
/* just for stats reporting */
struct list_head rs_item;
/* these have their own lock */
spinlock_t rs_rdma_lock;
struct rb_root rs_rdma_keys;
/* Socket options - in case there will be more */
unsigned char rs_recverr,
rs_cong_monitor;
};
static inline struct rds_sock *rds_sk_to_rs(const struct sock *sk)
{
return container_of(sk, struct rds_sock, rs_sk);
}
static inline struct sock *rds_rs_to_sk(struct rds_sock *rs)
{
return &rs->rs_sk;
}
/*
* The stack assigns sk_sndbuf and sk_rcvbuf to twice the specified value
* to account for overhead. We don't account for overhead, we just apply
* the number of payload bytes to the specified value.
*/
static inline int rds_sk_sndbuf(struct rds_sock *rs)
{
return rds_rs_to_sk(rs)->sk_sndbuf / 2;
}
static inline int rds_sk_rcvbuf(struct rds_sock *rs)
{
return rds_rs_to_sk(rs)->sk_rcvbuf / 2;
}
struct rds_statistics {
uint64_t s_conn_reset;
uint64_t s_recv_drop_bad_checksum;
uint64_t s_recv_drop_old_seq;
uint64_t s_recv_drop_no_sock;
uint64_t s_recv_drop_dead_sock;
uint64_t s_recv_deliver_raced;
uint64_t s_recv_delivered;
uint64_t s_recv_queued;
uint64_t s_recv_immediate_retry;
uint64_t s_recv_delayed_retry;
uint64_t s_recv_ack_required;
uint64_t s_recv_rdma_bytes;
uint64_t s_recv_ping;
uint64_t s_send_queue_empty;
uint64_t s_send_queue_full;
uint64_t s_send_sem_contention;
uint64_t s_send_sem_queue_raced;
uint64_t s_send_immediate_retry;
uint64_t s_send_delayed_retry;
uint64_t s_send_drop_acked;
uint64_t s_send_ack_required;
uint64_t s_send_queued;
uint64_t s_send_rdma;
uint64_t s_send_rdma_bytes;
uint64_t s_send_pong;
uint64_t s_page_remainder_hit;
uint64_t s_page_remainder_miss;
uint64_t s_copy_to_user;
uint64_t s_copy_from_user;
uint64_t s_cong_update_queued;
uint64_t s_cong_update_received;
uint64_t s_cong_send_error;
uint64_t s_cong_send_blocked;
};
/* af_rds.c */
void rds_sock_addref(struct rds_sock *rs);
void rds_sock_put(struct rds_sock *rs);
void rds_wake_sk_sleep(struct rds_sock *rs);
static inline void __rds_wake_sk_sleep(struct sock *sk)
{
wait_queue_head_t *waitq = sk->sk_sleep;
if (!sock_flag(sk, SOCK_DEAD) && waitq)
wake_up(waitq);
}
extern wait_queue_head_t rds_poll_waitq;
/* bind.c */
int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len);
void rds_remove_bound(struct rds_sock *rs);
struct rds_sock *rds_find_bound(__be32 addr, __be16 port);
/* cong.c */
int rds_cong_get_maps(struct rds_connection *conn);
void rds_cong_add_conn(struct rds_connection *conn);
void rds_cong_remove_conn(struct rds_connection *conn);
void rds_cong_set_bit(struct rds_cong_map *map, __be16 port);
void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port);
int rds_cong_wait(struct rds_cong_map *map, __be16 port, int nonblock, struct rds_sock *rs);
void rds_cong_queue_updates(struct rds_cong_map *map);
void rds_cong_map_updated(struct rds_cong_map *map, uint64_t);
int rds_cong_updated_since(unsigned long *recent);
void rds_cong_add_socket(struct rds_sock *);
void rds_cong_remove_socket(struct rds_sock *);
void rds_cong_exit(void);
struct rds_message *rds_cong_update_alloc(struct rds_connection *conn);
/* conn.c */
int __init rds_conn_init(void);
void rds_conn_exit(void);
struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
struct rds_transport *trans, gfp_t gfp);
struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
struct rds_transport *trans, gfp_t gfp);
void rds_conn_destroy(struct rds_connection *conn);
void rds_conn_reset(struct rds_connection *conn);
void rds_conn_drop(struct rds_connection *conn);
void rds_for_each_conn_info(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens,
int (*visitor)(struct rds_connection *, void *),
size_t item_len);
void __rds_conn_error(struct rds_connection *conn, const char *, ...)
__attribute__ ((format (printf, 2, 3)));
#define rds_conn_error(conn, fmt...) \
__rds_conn_error(conn, KERN_WARNING "RDS: " fmt)
static inline int
rds_conn_transition(struct rds_connection *conn, int old, int new)
{
return atomic_cmpxchg(&conn->c_state, old, new) == old;
}
static inline int
rds_conn_state(struct rds_connection *conn)
{
return atomic_read(&conn->c_state);
}
static inline int
rds_conn_up(struct rds_connection *conn)
{
return atomic_read(&conn->c_state) == RDS_CONN_UP;
}
static inline int
rds_conn_connecting(struct rds_connection *conn)
{
return atomic_read(&conn->c_state) == RDS_CONN_CONNECTING;
}
/* message.c */
struct rds_message *rds_message_alloc(unsigned int nents, gfp_t gfp);
struct rds_message *rds_message_copy_from_user(struct iovec *first_iov,
size_t total_len);
struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len);
void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
__be16 dport, u64 seq);
int rds_message_add_extension(struct rds_header *hdr,
unsigned int type, const void *data, unsigned int len);
int rds_message_next_extension(struct rds_header *hdr,
unsigned int *pos, void *buf, unsigned int *buflen);
int rds_message_add_version_extension(struct rds_header *hdr, unsigned int version);
int rds_message_get_version_extension(struct rds_header *hdr, unsigned int *version);
int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset);
int rds_message_inc_copy_to_user(struct rds_incoming *inc,
struct iovec *first_iov, size_t size);
void rds_message_inc_purge(struct rds_incoming *inc);
void rds_message_inc_free(struct rds_incoming *inc);
void rds_message_addref(struct rds_message *rm);
void rds_message_put(struct rds_message *rm);
void rds_message_wait(struct rds_message *rm);
void rds_message_unmapped(struct rds_message *rm);
static inline void rds_message_make_checksum(struct rds_header *hdr)
{
hdr->h_csum = 0;
hdr->h_csum = ip_fast_csum((void *) hdr, sizeof(*hdr) >> 2);
}
static inline int rds_message_verify_checksum(const struct rds_header *hdr)
{
return !hdr->h_csum || ip_fast_csum((void *) hdr, sizeof(*hdr) >> 2) == 0;
}
/* page.c */
int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
gfp_t gfp);
int rds_page_copy_user(struct page *page, unsigned long offset,
void __user *ptr, unsigned long bytes,
int to_user);
#define rds_page_copy_to_user(page, offset, ptr, bytes) \
rds_page_copy_user(page, offset, ptr, bytes, 1)
#define rds_page_copy_from_user(page, offset, ptr, bytes) \
rds_page_copy_user(page, offset, ptr, bytes, 0)
void rds_page_exit(void);
/* recv.c */
void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
__be32 saddr);
void rds_inc_addref(struct rds_incoming *inc);
void rds_inc_put(struct rds_incoming *inc);
void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
struct rds_incoming *inc, gfp_t gfp, enum km_type km);
int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
size_t size, int msg_flags);
void rds_clear_recv_queue(struct rds_sock *rs);
int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msg);
void rds_inc_info_copy(struct rds_incoming *inc,
struct rds_info_iterator *iter,
__be32 saddr, __be32 daddr, int flip);
/* send.c */
int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
size_t payload_len);
void rds_send_reset(struct rds_connection *conn);
int rds_send_xmit(struct rds_connection *conn);
struct sockaddr_in;
void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest);
typedef int (*is_acked_func)(struct rds_message *rm, uint64_t ack);
void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
is_acked_func is_acked);
int rds_send_acked_before(struct rds_connection *conn, u64 seq);
void rds_send_remove_from_sock(struct list_head *messages, int status);
int rds_send_pong(struct rds_connection *conn, __be16 dport);
struct rds_message *rds_send_get_message(struct rds_connection *,
struct rds_rdma_op *);
/* rdma.c */
void rds_rdma_unuse(struct rds_sock *rs, u32 r_key, int force);
/* stats.c */
DECLARE_PER_CPU_SHARED_ALIGNED(struct rds_statistics, rds_stats);
#define rds_stats_inc_which(which, member) do { \
per_cpu(which, get_cpu()).member++; \
put_cpu(); \
} while (0)
#define rds_stats_inc(member) rds_stats_inc_which(rds_stats, member)
#define rds_stats_add_which(which, member, count) do { \
per_cpu(which, get_cpu()).member += count; \
put_cpu(); \
} while (0)
#define rds_stats_add(member, count) rds_stats_add_which(rds_stats, member, count)
int __init rds_stats_init(void);
void rds_stats_exit(void);
void rds_stats_info_copy(struct rds_info_iterator *iter,
uint64_t *values, const char *const *names,
size_t nr);
/* sysctl.c */
int __init rds_sysctl_init(void);
void rds_sysctl_exit(void);
extern unsigned long rds_sysctl_sndbuf_min;
extern unsigned long rds_sysctl_sndbuf_default;
extern unsigned long rds_sysctl_sndbuf_max;
extern unsigned long rds_sysctl_reconnect_min_jiffies;
extern unsigned long rds_sysctl_reconnect_max_jiffies;
extern unsigned int rds_sysctl_max_unacked_packets;
extern unsigned int rds_sysctl_max_unacked_bytes;
extern unsigned int rds_sysctl_ping_enable;
extern unsigned long rds_sysctl_trace_flags;
extern unsigned int rds_sysctl_trace_level;
/* threads.c */
int __init rds_threads_init(void);
void rds_threads_exit(void);
extern struct workqueue_struct *rds_wq;
void rds_connect_worker(struct work_struct *);
void rds_shutdown_worker(struct work_struct *);
void rds_send_worker(struct work_struct *);
void rds_recv_worker(struct work_struct *);
void rds_connect_complete(struct rds_connection *conn);
/* transport.c */
int rds_trans_register(struct rds_transport *trans);
void rds_trans_unregister(struct rds_transport *trans);
struct rds_transport *rds_trans_get_preferred(__be32 addr);
unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
unsigned int avail);
int __init rds_trans_init(void);
void rds_trans_exit(void);
#endif
