[SCSI] iscsi: add libiscsi

There is a lot of code duplcited between iscsi_tcp
and the upcoming iscsi_iser driver. This patch puts
the duplicated code in a lib. There is more code
to move around but this takes care of the
basics. For iscsi_offload if they use the lib we will
probably move some things around. For example in the
queuecommand we will not assume that the LLD wants
to do queue_work, but it is better to handle that
later when we know for sure what iscsi_offload looks
like (we could probably do this for iscsi_iser though to).

Ideally I would like to get the iscsi_transports modules
to a place where all they really have to do is put data
on the wire, but how to do that will hopefully be more clear
when we see other modules like iscsi_offload. Or maybe
iscsi_offload will not use the lib and it will just be
iscsi_iser and iscsi_tcp and maybe the iscsi_tcp_tgt if that
is allowed in mainline.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 286 insertions, 0 deletions

diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
new file mode 100644
index 0000000..830700a
--- /dev/null
+++ b/include/scsi/libiscsi.h
@@ -0,0 +1,286 @@
+/*
+ * iSCSI lib definitions
+ *
+ * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2004 - 2006 Mike Christie
+ * Copyright (C) 2004 - 2005 Dmitry Yusupov
+ * Copyright (C) 2004 - 2005 Alex Aizman
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#ifndef LIBISCSI_H
+#define LIBISCSI_H
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <scsi/iscsi_proto.h>
+#include <scsi/iscsi_if.h>
+
+struct scsi_transport_template;
+struct scsi_device;
+struct Scsi_Host;
+struct scsi_cmnd;
+struct socket;
+struct iscsi_transport;
+struct iscsi_cls_session;
+struct iscsi_cls_conn;
+struct iscsi_session;
+struct iscsi_nopin;
+
+/* #define DEBUG_SCSI */
+#ifdef DEBUG_SCSI
+#define debug_scsi(fmt...) printk(KERN_INFO "scsi: " fmt)
+#else
+#define debug_scsi(fmt...)
+#endif
+
+#define ISCSI_XMIT_CMDS_MAX	128	/* must be power of 2 */
+#define ISCSI_MGMT_CMDS_MAX	32	/* must be power of 2 */
+#define ISCSI_CONN_MAX			1
+
+#define ISCSI_MGMT_ITT_OFFSET	0xa00
+
+#define ISCSI_DEF_CMD_PER_LUN		32
+#define ISCSI_MAX_CMD_PER_LUN		128
+
+/* Task Mgmt states */
+#define TMABORT_INITIAL			0x0
+#define TMABORT_SUCCESS			0x1
+#define TMABORT_FAILED			0x2
+#define TMABORT_TIMEDOUT		0x3
+
+/* Connection suspend "bit" */
+#define ISCSI_SUSPEND_BIT		1
+
+#define ISCSI_ITT_MASK			(0xfff)
+#define ISCSI_CID_SHIFT			12
+#define ISCSI_CID_MASK			(0xffff << ISCSI_CID_SHIFT)
+#define ISCSI_AGE_SHIFT			28
+#define ISCSI_AGE_MASK			(0xf << ISCSI_AGE_SHIFT)
+
+struct iscsi_mgmt_task {
+	/*
+	 * Becuae LLDs allocate their hdr differently, this is a pointer to
+	 * that storage. It must be setup at session creation time.
+	 */
+	struct iscsi_hdr	*hdr;
+	char			*data;		/* mgmt payload */
+	int			data_count;	/* counts data to be sent */
+	uint32_t		itt;		/* this ITT */
+	void			*dd_data;	/* driver/transport data */
+	struct list_head	running;
+};
+
+struct iscsi_cmd_task {
+	/*
+	 * Becuae LLDs allocate their hdr differently, this is a pointer to
+	 * that storage. It must be setup at session creation time.
+	 */
+	struct iscsi_cmd	*hdr;
+	int			itt;		/* this ITT */
+	int			datasn;		/* DataSN */
+
+	uint32_t		unsol_datasn;
+	int			imm_count;	/* imm-data (bytes)   */
+	int			unsol_count;	/* unsolicited (bytes)*/
+	int			data_count;	/* remaining Data-Out */
+	struct scsi_cmnd	*sc;		/* associated SCSI cmd*/
+	int			total_length;
+	struct iscsi_conn	*conn;		/* used connection    */
+	struct iscsi_mgmt_task	*mtask;		/* tmf mtask in progr */
+
+	struct list_head	running;	/* running cmd list */
+	void			*dd_data;	/* driver/transport data */
+};
+
+struct iscsi_conn {
+	struct iscsi_cls_conn	*cls_conn;	/* ptr to class connection */
+	void			*dd_data;	/* iscsi_transport data */
+	struct iscsi_session	*session;	/* parent session */
+	/*
+	 * LLDs should set this lock. It protects the transport recv
+	 * code
+	 */
+	rwlock_t		*recv_lock;
+	/*
+	 * conn_stop() flag: stop to recover, stop to terminate
+	 */
+        int			stop_stage;
+
+	/* iSCSI connection-wide sequencing */
+	uint32_t		exp_statsn;
+
+	/* control data */
+	int			id;		/* CID */
+	struct list_head	item;		/* maintains list of conns */
+	int			c_stage;	/* connection state */
+	struct iscsi_mgmt_task	*login_mtask;	/* mtask used for login/text */
+	struct iscsi_mgmt_task	*mtask;		/* xmit mtask in progress */
+	struct iscsi_cmd_task	*ctask;		/* xmit ctask in progress */
+
+	/* xmit */
+	struct kfifo		*immqueue;	/* immediate xmit queue */
+	struct kfifo		*mgmtqueue;	/* mgmt (control) xmit queue */
+	struct list_head	mgmt_run_list;	/* list of control tasks */
+	struct kfifo		*xmitqueue;	/* data-path cmd queue */
+	struct list_head	run_list;	/* list of cmds in progress */
+	struct work_struct	xmitwork;	/* per-conn. xmit workqueue */
+	/*
+	 * serializes connection xmit, access to kfifos:
+	 * xmitqueue, immqueue, mgmtqueue
+	 */
+	struct mutex		xmitmutex;
+
+	unsigned long		suspend_tx;	/* suspend Tx */
+	unsigned long		suspend_rx;	/* suspend Rx */
+
+	/* abort */
+	wait_queue_head_t	ehwait;		/* used in eh_abort() */
+	struct iscsi_tm		tmhdr;
+	struct timer_list	tmabort_timer;
+	int			tmabort_state;	/* see TMABORT_INITIAL, etc.*/
+
+	/* negotiated params */
+	int			max_recv_dlength; /* initiator_max_recv_dsl*/
+	int			max_xmit_dlength; /* target_max_recv_dsl */
+	int			hdrdgst_en;
+	int			datadgst_en;
+
+	/* MIB-statistics */
+	uint64_t		txdata_octets;
+	uint64_t		rxdata_octets;
+	uint32_t		scsicmd_pdus_cnt;
+	uint32_t		dataout_pdus_cnt;
+	uint32_t		scsirsp_pdus_cnt;
+	uint32_t		datain_pdus_cnt;
+	uint32_t		r2t_pdus_cnt;
+	uint32_t		tmfcmd_pdus_cnt;
+	int32_t			tmfrsp_pdus_cnt;
+
+	/* custom statistics */
+	uint32_t		eh_abort_cnt;
+};
+
+struct iscsi_queue {
+	struct kfifo		*queue;		/* FIFO Queue */
+	void			**pool;		/* Pool of elements */
+	int			max;		/* Max number of elements */
+};
+
+struct iscsi_session {
+	/* iSCSI session-wide sequencing */
+	uint32_t		cmdsn;
+	uint32_t		exp_cmdsn;
+	uint32_t		max_cmdsn;
+
+	/* configuration */
+	int			initial_r2t_en;
+	int			max_r2t;
+	int			imm_data_en;
+	int			first_burst;
+	int			max_burst;
+	int			time2wait;
+	int			time2retain;
+	int			pdu_inorder_en;
+	int			dataseq_inorder_en;
+	int			erl;
+	int			ifmarker_en;
+	int			ofmarker_en;
+
+	/* control data */
+	struct iscsi_transport	*tt;
+	struct Scsi_Host	*host;
+	struct iscsi_conn	*leadconn;	/* leading connection */
+	spinlock_t		lock;		/* protects session state, *
+						 * sequence numbers,       *
+						 * session resources:      *
+						 * - cmdpool,		   *
+						 * - mgmtpool,		   *
+						 * - r2tpool		   */
+	int			state;		/* session state           */
+	int			recovery_failed;
+	struct list_head	item;
+	int			conn_cnt;
+	int			age;		/* counts session re-opens */
+
+	struct list_head	connections;	/* list of connections */
+	int			cmds_max;	/* size of cmds array */
+	struct iscsi_cmd_task	**cmds;		/* Original Cmds arr */
+	struct iscsi_queue	cmdpool;	/* PDU's pool */
+	int			mgmtpool_max;	/* size of mgmt array */
+	struct iscsi_mgmt_task	**mgmt_cmds;	/* Original mgmt arr */
+	struct iscsi_queue	mgmtpool;	/* Mgmt PDU's pool */
+};
+
+/*
+ * scsi host template
+ */
+extern int iscsi_change_queue_depth(struct scsi_device *sdev, int depth);
+extern int iscsi_eh_abort(struct scsi_cmnd *sc);
+extern int iscsi_eh_host_reset(struct scsi_cmnd *sc);
+extern int iscsi_queuecommand(struct scsi_cmnd *sc,
+			      void (*done)(struct scsi_cmnd *));
+
+/*
+ * session management
+ */
+extern struct iscsi_cls_session *
+iscsi_session_setup(struct iscsi_transport *, struct scsi_transport_template *,
+		    int, int, uint32_t, uint32_t *);
+extern void iscsi_session_teardown(struct iscsi_cls_session *);
+extern struct iscsi_session *class_to_transport_session(struct iscsi_cls_session *);
+extern void iscsi_start_session_recovery(struct iscsi_session *,
+					struct iscsi_conn *, int);
+extern void iscsi_session_recovery_timedout(struct iscsi_cls_session *);
+
+#define session_to_cls(_sess) \
+	hostdata_session(_sess->host->hostdata)
+
+/*
+ * connection management
+ */
+extern struct iscsi_cls_conn *iscsi_conn_setup(struct iscsi_cls_session *,
+					       uint32_t);
+extern void iscsi_conn_teardown(struct iscsi_cls_conn *);
+extern int iscsi_conn_start(struct iscsi_cls_conn *);
+extern void iscsi_conn_stop(struct iscsi_cls_conn *, int);
+extern int iscsi_conn_bind(struct iscsi_cls_session *, struct iscsi_cls_conn *,
+			   int);
+extern void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err);
+
+/*
+ * pdu and task processing
+ */
+extern int iscsi_check_assign_cmdsn(struct iscsi_session *,
+				    struct iscsi_nopin *);
+extern void iscsi_prep_unsolicit_data_pdu(struct iscsi_cmd_task *,
+					struct iscsi_data *hdr,
+					int transport_data_cnt);
+extern int iscsi_conn_send_pdu(struct iscsi_cls_conn *, struct iscsi_hdr *,
+				char *, uint32_t);
+extern int iscsi_complete_pdu(struct iscsi_conn *, struct iscsi_hdr *,
+			      char *, int);
+extern int __iscsi_complete_pdu(struct iscsi_conn *, struct iscsi_hdr *,
+				char *, int);
+extern int iscsi_verify_itt(struct iscsi_conn *, struct iscsi_hdr *,
+			    uint32_t *);
+
+/*
+ * generic helpers
+ */
+extern void iscsi_pool_free(struct iscsi_queue *, void **);
+extern int iscsi_pool_init(struct iscsi_queue *, int, void ***, int);
+
+#endif