path: root/net/rds/rds.h

#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 __printf(1, 2)
void 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_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
#define RDS_IN_XMIT		2

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 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_atomic_sent;
	unsigned int		c_xmit_rdma_sent;
	unsigned int		c_xmit_data_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 */
	wait_queue_head_t	c_waitq;

	struct list_head	c_map_item;
	unsigned long		c_map_queued;

	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;
};

struct rds_mr {
	struct rb_node		r_rb_node;
	atomic_t		r_refcount;
	u32			r_key;

	/* A copy of the creation flags */
	unsigned int		r_use_once:1;
	unsigned int		r_invalidate:1;
	unsigned int		r_write:1;

	/* This is for RDS_MR_DEAD.
	 * It would be nice & consistent to make this part of the above
	 * bit field here, but we need to use test_and_set_bit.
	 */
	unsigned long		r_state;
	struct rds_sock		*r_sock; /* back pointer to the socket that owns us */
	struct rds_transport	*r_trans;
	void			*r_trans_private;
};

/* Flags for mr->r_state */
#define RDS_MR_DEAD		0

static inline rds_rdma_cookie_t rds_rdma_make_cookie(u32 r_key, u32 offset)
{
	return r_key | (((u64) offset) << 32);
}

static inline u32 rds_rdma_cookie_key(rds_rdma_cookie_t cookie)
{
	return cookie;
}

static inline u32 rds_rdma_cookie_offset(rds_rdma_cookie_t cookie)
{
	return cookie >> 32;
}

/* atomic operation types */
#define RDS_ATOMIC_TYPE_CSWP		0
#define RDS_ATOMIC_TYPE_FADD		1

/*
 * 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;
	wait_queue_head_t	m_flush_wait;

	struct rds_sock		*m_rs;

	/* cookie to send to remote, in rds header */
	rds_rdma_cookie_t	m_rdma_cookie;

	unsigned int		m_used_sgs;
	unsigned int		m_total_sgs;

	void			*m_final_op;

	struct {
		struct rm_atomic_op {
			int			op_type;
			union {
				struct {
					uint64_t