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77a23c21aa
linux-next/include/scsi/scsi_transport_iscsi.h
Mike Christie 77a23c21aa [SCSI] libiscsi: fix iscsi cmdsn allocation 
The cmdsn allocation and pdu transmit code can race, and we can end
up sending a pdu with cmdsn 10 before a pdu with 5. The target will
then fail the connection/session. This patch fixes the problem by
delaying the cmdsn allocation until we are about to send the pdu.

This also removes the xmitmutex. We were using the connection xmitmutex
during error handling to handle races with mtask and ctask cleanup and
completion. For ctasks we now have nice refcounting and for the mtask,
if we hit the case where the mtask timesout and it is floating
around somewhere in the driver, we end up dropping the session.
And to handle session level cleanup, we use the xmit suspend bit
along with scsi_flush_queue and the session lock to make sure
that the xmit thread is not possibly transmitting a task while
we are trying to kill it.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Cc: Roland Dreier <rdreier@cisco.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2007-06-02 15:34:14 -04:00

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/*
* iSCSI transport class definitions
*
* Copyright (C) IBM Corporation, 2004
* Copyright (C) Mike Christie, 2004 - 2006
* Copyright (C) Dmitry Yusupov, 2004 - 2005
* Copyright (C) Alex Aizman, 2004 - 2005
*
* 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 SCSI_TRANSPORT_ISCSI_H
#define SCSI_TRANSPORT_ISCSI_H
#include <linux/device.h>
#include <scsi/iscsi_if.h>
struct scsi_transport_template;
struct iscsi_transport;
struct Scsi_Host;
struct iscsi_cls_conn;
struct iscsi_conn;
struct iscsi_cmd_task;
struct iscsi_mgmt_task;
struct sockaddr;
/**
* struct iscsi_transport - iSCSI Transport template
*
* @name: transport name
* @caps: iSCSI Data-Path capabilities
* @create_session: create new iSCSI session object
* @destroy_session: destroy existing iSCSI session object
* @create_conn: create new iSCSI connection
* @bind_conn: associate this connection with existing iSCSI session
* and specified transport descriptor
* @destroy_conn: destroy inactive iSCSI connection
* @set_param: set iSCSI parameter. Return 0 on success, -ENODATA
* when param is not supported, and a -Exx value on other
* error.
* @get_param get iSCSI parameter. Must return number of bytes
* copied to buffer on success, -ENODATA when param
* is not supported, and a -Exx value on other error
* @start_conn: set connection to be operational
* @stop_conn: suspend/recover/terminate connection
* @send_pdu: send iSCSI PDU, Login, Logout, NOP-Out, Reject, Text.
* @session_recovery_timedout: notify LLD a block during recovery timed out
* @init_cmd_task: Initialize a iscsi_cmd_task and any internal structs.
* Called from queuecommand with session lock held.
* @init_mgmt_task: Initialize a iscsi_mgmt_task and any internal structs.
* Called from iscsi_conn_send_generic with xmitmutex.
* @xmit_cmd_task: Requests LLD to transfer cmd task. Returns 0 or the
* the number of bytes transferred on success, and -Exyz
* value on error.
* @xmit_mgmt_task: Requests LLD to transfer mgmt task. Returns 0 or the
* the number of bytes transferred on success, and -Exyz
* value on error.
* @cleanup_cmd_task: requests LLD to fail cmd task. Called with xmitmutex
* and session->lock after the connection has been
* suspended and terminated during recovery. If called
* from abort task then connection is not suspended
* or terminated but sk_callback_lock is held
*
* Template API provided by iSCSI Transport
*/
struct iscsi_transport {
struct module *owner;
char *name;
unsigned int caps;
/* LLD sets this to indicate what values it can export to sysfs */
uint64_t param_mask;
uint64_t host_param_mask;
struct scsi_host_template *host_template;
/* LLD connection data size */
int conndata_size;
/* LLD session data size */
int sessiondata_size;
int max_lun;
unsigned int max_conn;
unsigned int max_cmd_len;
struct iscsi_cls_session *(*create_session) (struct iscsi_transport *it,
struct scsi_transport_template *t, uint32_t sn, uint32_t *hn);
void (*destroy_session) (struct iscsi_cls_session *session);
struct iscsi_cls_conn *(*create_conn) (struct iscsi_cls_session *sess,
uint32_t cid);
int (*bind_conn) (struct iscsi_cls_session *session,
struct iscsi_cls_conn *cls_conn,
uint64_t transport_eph, int is_leading);
int (*start_conn) (struct iscsi_cls_conn *conn);
void (*stop_conn) (struct iscsi_cls_conn *conn, int flag);
void (*destroy_conn) (struct iscsi_cls_conn *conn);
int (*set_param) (struct iscsi_cls_conn *conn, enum iscsi_param param,
char *buf, int buflen);
int (*get_conn_param) (struct iscsi_cls_conn *conn,
enum iscsi_param param, char *buf);
int (*get_session_param) (struct iscsi_cls_session *session,
enum iscsi_param param, char *buf);
int (*get_host_param) (struct Scsi_Host *shost,
enum iscsi_host_param param, char *buf);
int (*set_host_param) (struct Scsi_Host *shost,
enum iscsi_host_param param, char *buf,
int buflen);
int (*send_pdu) (struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
char *data, uint32_t data_size);
void (*get_stats) (struct iscsi_cls_conn *conn,
struct iscsi_stats *stats);
void (*init_cmd_task) (struct iscsi_cmd_task *ctask);
void (*init_mgmt_task) (struct iscsi_conn *conn,
struct iscsi_mgmt_task *mtask);
int (*xmit_cmd_task) (struct iscsi_conn *conn,
struct iscsi_cmd_task *ctask);
void (*cleanup_cmd_task) (struct iscsi_conn *conn,
struct iscsi_cmd_task *ctask);
int (*xmit_mgmt_task) (struct iscsi_conn *conn,
struct iscsi_mgmt_task *mtask);
void (*session_recovery_timedout) (struct iscsi_cls_session *session);
int (*ep_connect) (struct sockaddr *dst_addr, int non_blocking,
uint64_t *ep_handle);
int (*ep_poll) (uint64_t ep_handle, int timeout_ms);
void (*ep_disconnect) (uint64_t ep_handle);
int (*tgt_dscvr) (struct Scsi_Host *shost, enum iscsi_tgt_dscvr type,
uint32_t enable, struct sockaddr *dst_addr);
};
/*
* transport registration upcalls
*/
extern struct scsi_transport_template *iscsi_register_transport(struct iscsi_transport *tt);
extern int iscsi_unregister_transport(struct iscsi_transport *tt);
/*
* control plane upcalls
*/
extern void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error);
extern int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
char *data, uint32_t data_size);
/* Connection's states */
#define ISCSI_CONN_INITIAL_STAGE 0
#define ISCSI_CONN_STARTED 1
#define ISCSI_CONN_STOPPED 2
#define ISCSI_CONN_CLEANUP_WAIT 3
struct iscsi_cls_conn {
struct list_head conn_list; /* item in connlist */
void *dd_data; /* LLD private data */
struct iscsi_transport *transport;
uint32_t cid; /* connection id */
int active; /* must be accessed with the connlock */
struct device dev; /* sysfs transport/container device */
};
#define iscsi_dev_to_conn(_dev) \
container_of(_dev, struct iscsi_cls_conn, dev)
/* Session's states */
#define ISCSI_STATE_FREE 1
#define ISCSI_STATE_LOGGED_IN 2
#define ISCSI_STATE_FAILED 3
#define ISCSI_STATE_TERMINATE 4
#define ISCSI_STATE_IN_RECOVERY 5
#define ISCSI_STATE_RECOVERY_FAILED 6
struct iscsi_cls_session {
struct list_head sess_list; /* item in session_list */
struct list_head host_list;
struct iscsi_transport *transport;
/* recovery fields */
int recovery_tmo;
struct delayed_work recovery_work;
int target_id;
int sid; /* session id */
void *dd_data; /* LLD private data */
struct device dev; /* sysfs transport/container device */
};
#define iscsi_dev_to_session(_dev) \
container_of(_dev, struct iscsi_cls_session, dev)
#define iscsi_session_to_shost(_session) \
dev_to_shost(_session->dev.parent)
#define starget_to_session(_stgt) \
iscsi_dev_to_session(_stgt->dev.parent)
struct iscsi_host {
struct list_head sessions;
struct mutex mutex;
};
/*
* session and connection functions that can be used by HW iSCSI LLDs
*/
extern struct iscsi_cls_session *iscsi_alloc_session(struct Scsi_Host *shost,
struct iscsi_transport *transport);
extern int iscsi_add_session(struct iscsi_cls_session *session,
unsigned int target_id);
extern int iscsi_if_create_session_done(struct iscsi_cls_conn *conn);
extern int iscsi_if_destroy_session_done(struct iscsi_cls_conn *conn);
extern struct iscsi_cls_session *iscsi_create_session(struct Scsi_Host *shost,
struct iscsi_transport *t,
unsigned int target_id);
extern void iscsi_remove_session(struct iscsi_cls_session *session);
extern void iscsi_free_session(struct iscsi_cls_session *session);
extern int iscsi_destroy_session(struct iscsi_cls_session *session);
extern struct iscsi_cls_conn *iscsi_create_conn(struct iscsi_cls_session *sess,
uint32_t cid);
extern int iscsi_destroy_conn(struct iscsi_cls_conn *conn);
extern void iscsi_unblock_session(struct iscsi_cls_session *session);
extern void iscsi_block_session(struct iscsi_cls_session *session);
#endif
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