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linux/include/scsi/scsi_transport_iscsi.h
Mike Christie 3219e52941 [SCSI] iscsi: fix writepsace race 
We can race and misset the suspend bit if iscsi_write_space is
called then iscsi_send returns with a failure indicating
there is no space.

To handle this this patch returns a error upwards allowing xmitworker
to decide if we need to try and transmit again. For the no
write space case xmitworker will not retry, and instead
let iscsi_write_space queue it back up if needed (this relies
on the work queue code to properly requeue us if needed).

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-06-05 19:12:25 -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 mempool_zone;
struct iscsi_cls_conn;
struct iscsi_conn;
struct iscsi_cmd_task;
struct iscsi_mgmt_task;
/**
* 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 Data-Path operational parameter
* @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
* @suspend_conn_recv: susepend the recv side of the connection
* @termincate_conn: destroy socket connection. Called with mutex lock.
* @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 */
unsigned int 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,
uint32_t value);
int (*get_conn_param) (struct iscsi_cls_conn *conn,
enum iscsi_param param, uint32_t *value);
int (*get_session_param) (struct iscsi_cls_session *session,
enum iscsi_param param, uint32_t *value);
int (*get_conn_str_param) (struct iscsi_cls_conn *conn,
enum iscsi_param param, char *buf);
int (*get_session_str_param) (struct iscsi_cls_session *session,
enum iscsi_param param, char *buf);
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 (*suspend_conn_recv) (struct iscsi_conn *conn);
void (*terminate_conn) (struct iscsi_conn *conn);
void (*init_cmd_task) (struct iscsi_cmd_task *ctask);
void (*init_mgmt_task) (struct iscsi_conn *conn,
struct iscsi_mgmt_task *mtask,
char *data, uint32_t data_size);
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);
};
/*
* 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 */
/* portal/group values we got during discovery */
char *persistent_address;
int persistent_port;
/* portal/group values we are currently using */
char *address;
int port;
int active; /* must be accessed with the connlock */
struct device dev; /* sysfs transport/container device */
struct mempool_zone *z_error;
struct mempool_zone *z_pdu;
struct list_head freequeue;
};
#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;
/* iSCSI values used as unique id by userspace. */
char *targetname;
int tpgt;
/* recovery fields */
int recovery_tmo;
struct work_struct recovery_work;
int target_id;
int channel;
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)
struct iscsi_host {
int next_target_id;
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_create_session(struct Scsi_Host *shost,
struct iscsi_transport *t, int channel);
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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