text: #ifndef _RDS_IW_H
  #define _RDS_IW_H
  
  #include <linux/interrupt.h>
  #include <rdma/ib_verbs.h>
  #include <rdma/rdma_cm.h>
  #include "rds.h"
  #include "rdma_transport.h"
  
  #define RDS_FASTREG_SIZE		20
  #define RDS_FASTREG_POOL_SIZE		2048
  
  #define RDS_IW_MAX_SGE			8
  #define RDS_IW_RECV_SGE 		2
  
  #define RDS_IW_DEFAULT_RECV_WR		1024
  #define RDS_IW_DEFAULT_SEND_WR		256
  
  #define RDS_IW_SUPPORTED_PROTOCOLS	0x00000003	/* minor versions supported */
  
  extern struct list_head rds_iw_devices;
  
  /*
   * IB posts RDS_FRAG_SIZE fragments of pages to the receive queues to
   * try and minimize the amount of memory tied up both the device and
   * socket receive queues.
   */
  /* page offset of the final full frag that fits in the page */
  #define RDS_PAGE_LAST_OFF (((PAGE_SIZE  / RDS_FRAG_SIZE) - 1) * RDS_FRAG_SIZE)
  struct rds_page_frag {
  	struct list_head	f_item;
  	struct page		*f_page;
  	unsigned long		f_offset;
  	dma_addr_t 		f_mapped;
  };
  
  struct rds_iw_incoming {
  	struct list_head	ii_frags;
  	struct rds_incoming	ii_inc;
  };
  
  struct rds_iw_connect_private {
  	/* Add new fields at the end, and don't permute existing fields. */
  	__be32			dp_saddr;
  	__be32			dp_daddr;
  	u8			dp_protocol_major;
  	u8			dp_protocol_minor;
  	__be16			dp_protocol_minor_mask; /* bitmask */
  	__be32			dp_reserved1;
  	__be64			dp_ack_seq;
  	__be32			dp_credit;		/* non-zero enables flow ctl */
  };
  
  struct rds_iw_scatterlist {
  	struct scatterlist	*list;
  	unsigned int		len;
  	int			dma_len;
  	unsigned int		dma_npages;
  	unsigned int		bytes;
  };
  
  struct rds_iw_mapping {
  	spinlock_t		m_lock;	/* protect the mapping struct */
  	struct list_head	m_list;
  	struct rds_iw_mr	*m_mr;
  	uint32_t		m_rkey;
  	struct rds_iw_scatterlist m_sg;
  };
  
  struct rds_iw_send_work {
  	struct rds_message	*s_rm;
  
  	/* We should really put these into a union: */
  	struct rm_rdma_op	*s_op;
  	struct rds_iw_mapping	*s_mapping;
  	struct ib_mr		*s_mr;
  	struct ib_fast_reg_page_list *s_page_list;
  	unsigned char		s_remap_count;
  
  	struct ib_send_wr	s_wr;
  	struct ib_sge		s_sge[RDS_IW_MAX_SGE];
  	unsigned long		s_queued;
  };
  
  struct rds_iw_recv_work {
  	struct rds_iw_incoming 	*r_iwinc;
  	struct rds_page_frag	*r_frag;
  	struct ib_recv_wr	r_wr;
  	struct ib_sge		r_sge[2];
  };
  
  struct rds_iw_work_ring {
  	u32		w_nr;
  	u32		w_alloc_ptr;
  	u32		w_alloc_ctr;
  	u32		w_free_ptr;
  	atomic_t	w_free_ctr;
  };
  
  struct rds_iw_device;
  
  struct rds_iw_connection {
  
  	struct list_head	iw_node;
  	struct rds_iw_device 	*rds_iwdev;
  	struct rds_connection	*conn;
  
  	/* alphabet soup, IBTA style */
  	struct rdma_cm_id	*i_cm_id;
  	struct ib_pd		*i_pd;
  	struct ib_mr		*i_mr;
  	struct ib_cq		*i_send_cq;
  	struct ib_cq		*i_recv_cq;
  
  	/* tx */
  	struct rds_iw_work_ring	i_send_ring;
  	struct rds_message	*i_rm;
  	struct rds_header	*i_send_hdrs;
  	u64			i_send_hdrs_dma;
  	struct rds_iw_send_work *i_sends;
  
  	/* rx */
  	struct tasklet_struct	i_recv_tasklet;
  	struct mutex		i_recv_mutex;
  	struct rds_iw_work_ring	i_recv_ring;
  	struct rds_iw_incoming	*i_iwinc;
  	u32			i_recv_data_rem;
  	struct rds_header	*i_recv_hdrs;
  	u64			i_recv_hdrs_dma;
  	struct rds_iw_recv_work *i_recvs;
  	struct rds_page_frag	i_frag;
  	u64			i_ack_recv;	/* last ACK received */
  
  	/* sending acks */
  	unsigned long		i_ack_flags;
  #ifdef KERNEL_HAS_ATOMIC64
  	atomic64_t		i_ack_next;	/* next ACK to send */
  #else
  	spinlock_t		i_ack_lock;	/* protect i_ack_next */
  	u64			i_ack_next;	/* next ACK to send */
  #endif
  	struct rds_header	*i_ack;
  	struct ib_send_wr	i_ack_wr;
  	struct ib_sge		i_ack_sge;
  	u64			i_ack_dma;
  	unsigned long		i_ack_queued;
  
  	/* Flow control related information
  	 *
  	 * Our algorithm uses a pair variables that we need to access
  	 * atomically - one for the send credits, and one posted
  	 * recv credits we need to transfer to remote.
  	 * Rather than protect them using a slow spinlock, we put both into
  	 * a single atomic_t and update it using cmpxchg
  	 */
  	atomic_t		i_credits;
  
  	/* Protocol version specific information */
  	unsigned int		i_flowctl:1;	/* enable/disable flow ctl */
  	unsigned int		i_dma_local_lkey:1;
  	unsigned int		i_fastreg_posted:1; /* fastreg posted on this connection */
  	/* Batched completions */
  	unsigned int		i_unsignaled_wrs;
  	long			i_unsignaled_bytes;
  };
  
  /* This assumes that atomic_t is at least 32 bits */
  #define IB_GET_SEND_CREDITS(v)	((v) & 0xffff)
  #define IB_GET_POST_CREDITS(v)	((v) >> 16)
  #define IB_SET_SEND_CREDITS(v)	((v) & 0xffff)
  #define IB_SET_POST_CREDITS(v)	((v) << 16)
  
  struct rds_iw_cm_id {
  	struct list_head	list;
  	struct rdma_cm_id	*cm_id;
  };
  
  struct rds_iw_device {
  	struct list_head	list;
  	struct list_head	cm_id_list;
  	struct list_head	conn_list;
  	struct ib_device	*dev;
  	struct ib_pd		*pd;
  	struct ib_mr		*mr;
  	struct rds_iw_mr_pool	*mr_pool;
  	int			max_sge;
  	unsigned int		max_wrs;
  	unsigned int		dma_local_lkey:1;
  	spinlock_t		spinlock;	/* protect the above */
  };
  
  /* bits for i_ack_flags */
  #define IB_ACK_IN_FLIGHT	0
  #define IB_ACK_REQUESTED	1
  
  /* Magic WR_ID for ACKs */
  #define RDS_IW_ACK_WR_ID	((u64)0xffffffffffffffffULL)
  #define RDS_IW_FAST_REG_WR_ID	((u64)0xefefefefefefefefULL)
  #define RDS_IW_LOCAL_INV_WR_ID	((u64)0xdfdfdfdfdfdfdfdfULL)
  
  struct rds_iw_statistics {
  	uint64_t	s_iw_connect_raced;
  	uint64_t	s_iw_listen_closed_stale;
  	uint64_t	s_iw_tx_cq_call;
  	uint64_t	s_iw_tx_cq_event;
  	uint64_t	s_iw_tx_ring_full;
  	uint64_t	s_iw_tx_throttle;
  	uint64_t	s_iw_tx_sg_mapping_failure;
  	uint64_t	s_iw_tx_stalled;
  	uint64_t	s_iw_tx_credit_updates;
  	uint64_t	s_iw_rx_cq_call;
  	uint64_t	s_iw_rx_cq_event;
  	uint64_t	s_iw_rx_ring_empty;
  	uint64_t	s_iw_rx_refill_from_cq;
  	uint64_t	s_iw_rx_refill_from_thread;
  	uint64_t	s_iw_rx_alloc_limit;
  	uint64_t	s_iw_rx_credit_updates;
  	uint64_t	s_iw_ack_sent;
  	uint64_t	s_iw_ack_send_failure;
  	uint64_t	s_iw_ack_send_delayed;
  	uint64_t	s_iw_ack_send_piggybacked;
  	uint64_t	s_iw_ack_received;
  	uint64_t	s_iw_rdma_mr_alloc;
  	uint64_t	s_iw_rdma_mr_free;
  	uint64_t	s_iw_rdma_mr_used;
  	uint64_t	s_iw_rdma_mr_pool_flush;
  	uint64_t	s_iw_rdma_mr_pool_wait;
  	uint64_t	s_iw_rdma_mr_pool_depleted;
  };
  
  extern struct workqueue_struct *rds_iw_wq;
  
  /*
   * Fake ib_dma_sync_sg_for_{cpu,device} as long as ib_verbs.h
   * doesn't define it.
   */
  static inline void rds_iw_dma_sync_sg_for_cpu(struct ib_device *dev,
  		struct scatterlist *sg, unsigned int sg_dma_len, int direction)
  {
  	unsigned int i;
  
  	for (i = 0; i < sg_dma_len; ++i) {
  		ib_dma_sync_single_for_cpu(dev,
  				ib_sg_dma_address(dev, &sg[i]),
  				ib_sg_dma_len(dev, &sg[i]),
  				direction);
  	}
  }
  #define ib_dma_sync_sg_for_cpu	rds_iw_dma_sync_sg_for_cpu
  
  static inline void rds_iw_dma_sync_sg_for_device(struct ib_device *dev,
  		struct scatterlist *sg, unsigned int sg_dma_len, int direction)
  {
  	unsigned int i;
  
  	for (i = 0; i < sg_dma_len; ++i) {
  		ib_dma_sync_single_for_device(dev,
  				ib_sg_dma_address(dev, &sg[i]),
  				ib_sg_dma_len(dev, &sg[i]),
  				direction);
  	}
  }
  #define ib_dma_sync_sg_for_device	rds_iw_dma_sync_sg_for_device
  
  static inline u32 rds_iw_local_dma_lkey(struct rds_iw_connection *ic)
  {
  	return ic->i_dma_local_lkey ? ic->i_cm_id->device->local_dma_lkey : ic->i_mr->lkey;
  }
  
  /* ib.c */
  extern struct rds_transport rds_iw_transport;
  extern struct ib_client rds_iw_client;
  
  extern unsigned int fastreg_pool_size;
  extern unsigned int fastreg_message_size;
  
  extern spinlock_t iw_nodev_conns_lock;
  extern struct list_head iw_nodev_conns;
  
  /* ib_cm.c */
  int rds_iw_conn_alloc(struct rds_connection *conn, gfp_t gfp);
  void rds_iw_conn_free(void *arg);
  int rds_iw_conn_connect(struct rds_connection *conn);
  void rds_iw_conn_shutdown(struct rds_connection *conn);
  void rds_iw_state_change(struct sock *sk);
  int rds_iw_listen_init(void);
  void rds_iw_listen_stop(void);
  void __rds_iw_conn_error(struct rds_connection *conn, const char *, ...);
  int rds_iw_cm_handle_connect(struct rdma_cm_id *cm_id,
  			     struct rdma_cm_event *event);
  int rds_iw_cm_initiate_connect(struct rdma_cm_id *cm_id);
  void rds_iw_cm_connect_complete(struct rds_connection *conn,
  				struct rdma_cm_event *event);
  
  
  #define rds_iw_conn_error(conn, fmt...) \
  	__rds_iw_conn_error(conn, KERN_WARNING "RDS/IW: " fmt)
  
  /* ib_rdma.c */
  int rds_iw_update_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id);
  void rds_iw_add_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn);
  void rds_iw_remove_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn);
  void __rds_iw_destroy_conns(struct list_head *list, spinlock_t *list_lock);
  static inline void rds_iw_destroy_nodev_conns(void)
  {
  	__rds_iw_destroy_conns(&iw_nodev_conns, &iw_nodev_conns_lock);
  }
  static inline void rds_iw_destroy_conns(struct rds_iw_device *rds_iwdev)
  {
  	__rds_iw_destroy_conns(&rds_iwdev->conn_list, &rds_iwdev->spinlock);
  }
  struct rds_iw_mr_pool *rds_iw_create_mr_pool(struct rds_iw_device *);
  void rds_iw_get_mr_info(struct rds_iw_device *rds_iwdev, struct rds_info_rdma_connection *iinfo);
  void rds_iw_destroy_mr_pool(struct rds_iw_mr_pool *);
  void *rds_iw_get_mr(struct scatterlist *sg, unsigned long nents,
  		    struct rds_sock *rs, u32 *key_ret);
  void rds_iw_sync_mr(void *trans_private, int dir);
  void rds_iw_free_mr(void *trans_private, int invalidate);
  void rds_iw_flush_mrs(void);
  
  /* ib_recv.c */
  int rds_iw_recv_init(void);
  void rds_iw_recv_exit(void);
  int rds_iw_recv(struct rds_connection *conn);
  int rds_iw_recv_refill(struct rds_connection *conn, gfp_t kptr_gfp,
  		       gfp_t page_gfp, int prefill);
  void rds_iw_inc_free(struct rds_incoming *inc);
  int rds_iw_inc_copy_to_user(struct rds_incoming *inc, struct iovec *iov,
  			     size_t size);
  void rds_iw_recv_cq_comp_handler(struct ib_cq *cq, void *context);
  void rds_iw_recv_tasklet_fn(unsigned long data);
  void rds_iw_recv_init_ring(struct rds_iw_connection *ic);
  void rds_iw_recv_clear_ring(struct rds_iw_connection *ic);
  void rds_iw_recv_init_ack(struct rds_iw_connection *ic);
  void rds_iw_attempt_ack(struct rds_iw_connection *ic);
  void rds_iw_ack_send_complete(struct rds_iw_connection *ic);
  u64 rds_iw_piggyb_ack(struct rds_iw_connection *ic);
  
  /* ib_ring.c */
  void rds_iw_ring_init(struct rds_iw_work_ring *ring, u32 nr);
  void rds_iw_ring_resize(struct rds_iw_work_ring *ring, u32 nr);
  u32 rds_iw_ring_alloc(struct rds_iw_work_ring *ring, u32 val, u32 *pos);
  void rds_iw_ring_free(struct rds_iw_work_ring *ring, u32 val);
  void rds_iw_ring_unalloc(struct rds_iw_work_ring *ring, u32 val);
  int rds_iw_ring_empty(struct rds_iw_work_ring *ring);
  int rds_iw_ring_low(struct rds_iw_work_ring *ring);
  u32 rds_iw_ring_oldest(struct rds_iw_work_ring *ring);
  u32 rds_iw_ring_completed(struct rds_iw_work_ring *ring, u32 wr_id, u32 oldest);
  extern wait_queue_head_t rds_iw_ring_empty_wait;
  
  /* ib_send.c */
  void rds_iw_xmit_complete(struct rds_connection *conn);
  int rds_iw_xmit(struct rds_connection *conn, struct rds_message *rm,
  		unsigned int hdr_off, unsigned int sg, unsigned int off);
  void rds_iw_send_cq_comp_handler(struct ib_cq *cq, void *context);
  void rds_iw_send_init_ring(struct rds_iw_connection *ic);
  void rds_iw_send_clear_ring(struct rds_iw_connection *ic);
  int rds_iw_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op);
  void rds_iw_send_add_credits(struct rds_connection *conn, unsigned int credits);
  void rds_iw_advertise_credits(struct rds_connection *conn, unsigned int posted);
  int rds_iw_send_grab_credits(struct rds_iw_connection *ic, u32 wanted,
  			     u32 *adv_credits, int need_posted, int max_posted);
  
  /* ib_stats.c */
  DECLARE_PER_CPU(struct rds_iw_statistics, rds_iw_stats);
  #define rds_iw_stats_inc(member) rds_stats_inc_which(rds_iw_stats, member)
  unsigned int rds_iw_stats_info_copy(struct rds_info_iterator *iter,
  				    unsigned int avail);
  
  /* ib_sysctl.c */
  int rds_iw_sysctl_init(void);
  void rds_iw_sysctl_exit(void);
  extern unsigned long rds_iw_sysctl_max_send_wr;
  extern unsigned long rds_iw_sysctl_max_recv_wr;
  extern unsigned long rds_iw_sysctl_max_unsig_wrs;
  extern unsigned long rds_iw_sysctl_max_unsig_bytes;
  extern unsigned long rds_iw_sysctl_max_recv_allocation;
  extern unsigned int rds_iw_sysctl_flow_control;
  
  /*
   * Helper functions for getting/setting the header and data SGEs in
   * RDS packets (not RDMA)
   */
  static inline struct ib_sge *
  rds_iw_header_sge(struct rds_iw_connection *ic, struct ib_sge *sge)
  {
  	return &sge[0];
  }
  
  static inline struct ib_sge *
  rds_iw_data_sge(struct rds_iw_connection *ic, struct ib_sge *sge)
  {
  	return &sge[1];
  }
  
  #endif
  