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linux/include/scsi/scsi_transport_iscsi.h
Mike Christie 7c6e99c181 scsi: iscsi: Fix conn cleanup and stop race during iscsid restart 
If iscsid is doing a stop_conn at the same time the kernel is starting
error recovery we can hit a race that allows the cleanup work to run on a
valid connection. In the race, iscsi_if_stop_conn sees the cleanup bit set,
but it calls flush_work on the clean_work before iscsi_conn_error_event has
queued it. The flush then returns before the queueing and so the
cleanup_work can run later and disconnect/stop a conn while it's in a
connected state.

The patch:

Commit 0ab710458d ("scsi: iscsi: Perform connection failure entirely in
kernel space")

added the late stop_conn call bug originally, and the patch:

Commit 23d6fefbb3 ("scsi: iscsi: Fix in-kernel conn failure handling")

attempted to fix it but only fixed the normal EH case and left the above
race for the iscsid restart case. For the normal EH case we don't hit the
race because we only signal userspace to start recovery after we have done
the queueing, so the flush will always catch the queued work or see it
completed.

For iscsid restart cases like boot, we can hit the race because iscsid will
call down to the kernel before the kernel has signaled any error, so both
code paths can be running at the same time. This adds a lock around the
setting of the cleanup bit and queueing so they happen together.

Link: https://lore.kernel.org/r/20220408001314.5014-6-michael.christie@oracle.com
Fixes: 0ab710458d ("scsi: iscsi: Perform connection failure entirely in kernel space")
Tested-by: Manish Rangankar <mrangankar@marvell.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2022-04-11 22:09:34 -04:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* 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
*/
#ifndef SCSI_TRANSPORT_ISCSI_H
#define SCSI_TRANSPORT_ISCSI_H
#include <linux/device.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <scsi/iscsi_if.h>
struct scsi_transport_template;
struct iscsi_transport;
struct iscsi_endpoint;
struct Scsi_Host;
struct scsi_cmnd;
struct iscsi_cls_conn;
struct iscsi_conn;
struct iscsi_task;
struct sockaddr;
struct iscsi_iface;
struct bsg_job;
struct iscsi_bus_flash_session;
struct iscsi_bus_flash_conn;
/**
* 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_task: Initialize a iscsi_task and any internal structs.
* When offloading the data path, this is called from
* queuecommand with the session lock, or from the
* iscsi_conn_send_pdu context with the session lock.
* When not offloading the data path, this is called
* from the scsi work queue without the session lock.
* @xmit_task Requests LLD to transfer cmd task. Returns 0 or the
* number of bytes transferred on success, and -Exyz
* value on error. When offloading the data path, this
* is called from queuecommand with the session lock, or
* from the iscsi_conn_send_pdu context with the session
* lock. When not offloading the data path, this is called
* from the scsi work queue without the session lock.
* @cleanup_task: requests LLD to fail task. Called with session lock
* and 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;
struct iscsi_cls_session *(*create_session) (struct iscsi_endpoint *ep,
uint16_t cmds_max, uint16_t qdepth,
uint32_t sn);
void (*destroy_session) (struct iscsi_cls_session *session);
struct iscsi_cls_conn *(*create_conn) (struct iscsi_cls_session *sess,
uint32_t cid);
void (*unbind_conn) (struct iscsi_cls_conn *conn, bool is_active);
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_ep_param) (struct iscsi_endpoint *ep, enum iscsi_param param,
char *buf);
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);
int (*init_task) (struct iscsi_task *task);
int (*xmit_task) (struct iscsi_task *task);
void (*cleanup_task) (struct iscsi_task *task);
int (*alloc_pdu) (struct iscsi_task *task, uint8_t opcode);
int (*xmit_pdu) (struct iscsi_task *task);
int (*init_pdu) (struct iscsi_task *task, unsigned int offset,
unsigned int count);
void (*parse_pdu_itt) (struct iscsi_conn *conn, itt_t itt,
int *index, int *age);
void (*session_recovery_timedout) (struct iscsi_cls_session *session);
struct iscsi_endpoint *(*ep_connect) (struct Scsi_Host *shost,
struct sockaddr *dst_addr,
int non_blocking);
int (*ep_poll) (struct iscsi_endpoint *ep, int timeout_ms);
void (*ep_disconnect) (struct iscsi_endpoint *ep);
int (*tgt_dscvr) (struct Scsi_Host *shost, enum iscsi_tgt_dscvr type,
uint32_t enable, struct sockaddr *dst_addr);
int (*set_path) (struct Scsi_Host *shost, struct iscsi_path *params);
int (*set_iface_param) (struct Scsi_Host *shost, void *data,
uint32_t len);
int (*get_iface_param) (struct iscsi_iface *iface,
enum iscsi_param_type param_type,
int param, char *buf);
umode_t (*attr_is_visible)(int param_type, int param);
int (*bsg_request)(struct bsg_job *job);
int (*send_ping) (struct Scsi_Host *shost, uint32_t iface_num,
uint32_t iface_type, uint32_t payload_size,
uint32_t pid, struct sockaddr *dst_addr);
int (*get_chap) (struct Scsi_Host *shost, uint16_t chap_tbl_idx,
uint32_t *num_entries, char *buf);
int (*delete_chap) (struct Scsi_Host *shost, uint16_t chap_tbl_idx);
int (*set_chap) (struct Scsi_Host *shost, void *data, int len);
int (*get_flashnode_param) (struct iscsi_bus_flash_session *fnode_sess,
int param, char *buf);
int (*set_flashnode_param) (struct iscsi_bus_flash_session *fnode_sess,
struct iscsi_bus_flash_conn *fnode_conn,
void *data, int len);
int (*new_flashnode) (struct Scsi_Host *shost, const char *buf,
int len);
int (*del_flashnode) (struct iscsi_bus_flash_session *fnode_sess);
int (*login_flashnode) (struct iscsi_bus_flash_session *fnode_sess,
struct iscsi_bus_flash_conn *fnode_conn);
int (*logout_flashnode) (struct iscsi_bus_flash_session *fnode_sess,
struct iscsi_bus_flash_conn *fnode_conn);
int (*logout_flashnode_sid) (struct iscsi_cls_session *cls_sess);
int (*get_host_stats) (struct Scsi_Host *shost, char *buf, int len);
u8 (*check_protection)(struct iscsi_task *task, sector_t *sector);
};
/*
* 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_event(struct iscsi_cls_conn *conn,
enum iscsi_err error);
extern void iscsi_conn_login_event(struct iscsi_cls_conn *conn,
enum iscsi_conn_state state);
extern int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
char *data, uint32_t data_size);
extern int iscsi_offload_mesg(struct Scsi_Host *shost,
struct iscsi_transport *transport, uint32_t type,
char *data, uint16_t data_size);
extern void iscsi_post_host_event(uint32_t host_no,
struct iscsi_transport *transport,
enum iscsi_host_event_code code,
uint32_t data_size,
uint8_t *data);
extern void iscsi_ping_comp_event(uint32_t host_no,
struct iscsi_transport *transport,
uint32_t status, uint32_t pid,
uint32_t data_size, uint8_t *data);
/* iscsi class connection state */
enum iscsi_connection_state {
ISCSI_CONN_UP = 0,
ISCSI_CONN_DOWN,
ISCSI_CONN_FAILED,
ISCSI_CONN_BOUND,
};
#define ISCSI_CLS_CONN_BIT_CLEANUP 1
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 */
/*
* This protects the conn startup and binding/unbinding of the ep to
* the conn. Unbinding includes ep_disconnect and stop_conn.
*/
struct mutex ep_mutex;
struct iscsi_endpoint *ep;
/* Used when accessing flags and queueing work. */
spinlock_t lock;
unsigned long flags;
struct work_struct cleanup_work;
struct device dev; /* sysfs transport/container device */
enum iscsi_connection_state state;
};
#define iscsi_dev_to_conn(_dev) \
container_of(_dev, struct iscsi_cls_conn, dev)
#define transport_class_to_conn(_cdev) \
iscsi_dev_to_conn(_cdev->parent)
#define iscsi_conn_to_session(_conn) \
iscsi_dev_to_session(_conn->dev.parent)
/* iscsi class session state */
enum {
ISCSI_SESSION_LOGGED_IN,
ISCSI_SESSION_FAILED,
ISCSI_SESSION_FREE,
};
#define ISCSI_MAX_TARGET -1
struct iscsi_cls_session {
struct list_head sess_list; /* item in session_list */
struct iscsi_transport *transport;
spinlock_t lock;
struct work_struct block_work;
struct work_struct unblock_work;
struct work_struct scan_work;
struct work_struct unbind_work;
struct work_struct destroy_work;
/* recovery fields */
int recovery_tmo;
bool recovery_tmo_sysfs_override;
struct delayed_work recovery_work;
struct workqueue_struct *workq;
unsigned int target_id;
bool ida_used;
/*
* pid of userspace process that created session or -1 if
* created by the kernel.
*/
pid_t creator;
int state;
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 transport_class_to_session(_cdev) \
iscsi_dev_to_session(_cdev->parent)
#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_cls_host {
struct mutex mutex;
struct request_queue *bsg_q;
uint32_t port_speed;
uint32_t port_state;
};
#define iscsi_job_to_shost(_job) \
dev_to_shost(_job->dev)
extern void iscsi_host_for_each_session(struct Scsi_Host *shost,
void (*fn)(struct iscsi_cls_session *));
struct iscsi_endpoint {
void *dd_data; /* LLD private data */
struct device dev;
int id;
struct iscsi_cls_conn *conn;
};
struct iscsi_iface {
struct device dev;
struct iscsi_transport *transport;
uint32_t iface_type; /* IPv4 or IPv6 */
uint32_t iface_num; /* iface number, 0 - n */
void *dd_data; /* LLD private data */
};
#define iscsi_dev_to_iface(_dev) \
container_of(_dev, struct iscsi_iface, dev)
#define iscsi_iface_to_shost(_iface) \
dev_to_shost(_iface->dev.parent)
struct iscsi_bus_flash_conn {
struct list_head conn_list; /* item in connlist */
void *dd_data; /* LLD private data */
struct iscsi_transport *transport;
struct device dev; /* sysfs transport/container device */
/* iscsi connection parameters */
uint32_t exp_statsn;
uint32_t statsn;
unsigned max_recv_dlength; /* initiator_max_recv_dsl*/
unsigned max_xmit_dlength; /* target_max_recv_dsl */
unsigned max_segment_size;
unsigned tcp_xmit_wsf;
unsigned tcp_recv_wsf;
int hdrdgst_en;
int datadgst_en;
int port;
char *ipaddress;
char *link_local_ipv6_addr;
char *redirect_ipaddr;
uint16_t keepalive_timeout;
uint16_t local_port;
uint8_t snack_req_en;
/* tcp timestamp negotiation status */
uint8_t tcp_timestamp_stat;
uint8_t tcp_nagle_disable;
/* tcp window scale factor */
uint8_t tcp_wsf_disable;
uint8_t tcp_timer_scale;
uint8_t tcp_timestamp_en;
uint8_t ipv4_tos;
uint8_t ipv6_traffic_class;
uint8_t ipv6_flow_label;
uint8_t fragment_disable;
/* Link local IPv6 address is assigned by firmware or driver */
uint8_t is_fw_assigned_ipv6;
};
#define iscsi_dev_to_flash_conn(_dev) \
container_of(_dev, struct iscsi_bus_flash_conn, dev)
#define iscsi_flash_conn_to_flash_session(_conn) \
iscsi_dev_to_flash_session(_conn->dev.parent)
#define ISID_SIZE 6
struct iscsi_bus_flash_session {
struct list_head sess_list; /* item in session_list */
struct iscsi_transport *transport;
unsigned int target_id;
int flash_state; /* persistent or non-persistent */
void *dd_data; /* LLD private data */
struct device dev; /* sysfs transport/container device */
/* iscsi session parameters */
unsigned first_burst;
unsigned max_burst;
unsigned short max_r2t;
int default_taskmgmt_timeout;
int initial_r2t_en;
int imm_data_en;
int time2wait;
int time2retain;
int pdu_inorder_en;
int dataseq_inorder_en;
int erl;
int tpgt;
char *username;
char *username_in;
char *password;
char *password_in;
char *targetname;
char *targetalias;
char *portal_type;
uint16_t tsid;
uint16_t chap_in_idx;
uint16_t chap_out_idx;
/* index of iSCSI discovery session if the entry is
* discovered by iSCSI discovery session
*/
uint16_t discovery_parent_idx;
/* indicates if discovery was done through iSNS discovery service
* or through sendTarget */
uint16_t discovery_parent_type;
/* Firmware auto sendtarget discovery disable */
uint8_t auto_snd_tgt_disable;
uint8_t discovery_sess;
/* indicates if this flashnode entry is enabled or disabled */
uint8_t entry_state;
uint8_t chap_auth_en;
/* enables firmware to auto logout the discovery session on discovery
* completion
*/
uint8_t discovery_logout_en;
uint8_t bidi_chap_en;
/* makes authentication for discovery session optional */
uint8_t discovery_auth_optional;
uint8_t isid[ISID_SIZE];
uint8_t is_boot_target;
};
#define iscsi_dev_to_flash_session(_dev) \
container_of(_dev, struct iscsi_bus_flash_session, dev)
#define iscsi_flash_session_to_shost(_session) \
dev_to_shost(_session->dev.parent)
/*
* session and connection functions that can be used by HW iSCSI LLDs
*/
#define iscsi_cls_session_printk(prefix, _cls_session, fmt, a...) \
dev_printk(prefix, &(_cls_session)->dev, fmt, ##a)
#define iscsi_cls_conn_printk(prefix, _cls_conn, fmt, a...) \
dev_printk(prefix, &(_cls_conn)->dev, fmt, ##a)
extern int iscsi_session_chkready(struct iscsi_cls_session *session);
extern int iscsi_is_session_online(struct iscsi_cls_session *session);
extern struct iscsi_cls_session *iscsi_alloc_session(struct Scsi_Host *shost,
struct iscsi_transport *transport, int dd_size);
extern int iscsi_add_session(struct iscsi_cls_session *session,
unsigned int target_id);
extern int iscsi_session_event(struct iscsi_cls_session *session,
enum iscsi_uevent_e event);
extern struct iscsi_cls_session *iscsi_create_session(struct Scsi_Host *shost,
struct iscsi_transport *t,
int dd_size,
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 struct iscsi_cls_conn *iscsi_alloc_conn(struct iscsi_cls_session *sess,
int dd_size, uint32_t cid);
extern int iscsi_add_conn(struct iscsi_cls_conn *conn);
extern void iscsi_remove_conn(struct iscsi_cls_conn *conn);
extern void iscsi_put_conn(struct iscsi_cls_conn *conn);
extern void iscsi_get_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);
extern struct iscsi_endpoint *iscsi_create_endpoint(int dd_size);
extern void iscsi_destroy_endpoint(struct iscsi_endpoint *ep);
extern struct iscsi_endpoint *iscsi_lookup_endpoint(u64 handle);
extern void iscsi_put_endpoint(struct iscsi_endpoint *ep);
extern int iscsi_block_scsi_eh(struct scsi_cmnd *cmd);
extern struct iscsi_iface *iscsi_create_iface(struct Scsi_Host *shost,
struct iscsi_transport *t,
uint32_t iface_type,
uint32_t iface_num, int dd_size);
extern void iscsi_destroy_iface(struct iscsi_iface *iface);
extern struct iscsi_iface *iscsi_lookup_iface(int handle);
extern char *iscsi_get_port_speed_name(struct Scsi_Host *shost);
extern char *iscsi_get_port_state_name(struct Scsi_Host *shost);
extern int iscsi_is_session_dev(const struct device *dev);
extern char *iscsi_get_discovery_parent_name(int parent_type);
extern struct device *
iscsi_find_flashnode(struct Scsi_Host *shost, void *data,
int (*fn)(struct device *dev, void *data));
extern struct iscsi_bus_flash_session *
iscsi_create_flashnode_sess(struct Scsi_Host *shost, int index,
struct iscsi_transport *transport, int dd_size);
extern struct iscsi_bus_flash_conn *
iscsi_create_flashnode_conn(struct Scsi_Host *shost,
struct iscsi_bus_flash_session *fnode_sess,
struct iscsi_transport *transport, int dd_size);
extern void
iscsi_destroy_flashnode_sess(struct iscsi_bus_flash_session *fnode_sess);
extern void iscsi_destroy_all_flashnode(struct Scsi_Host *shost);
extern int iscsi_flashnode_bus_match(struct device *dev,
struct device_driver *drv);
extern struct device *
iscsi_find_flashnode_sess(struct Scsi_Host *shost, void *data,
int (*fn)(struct device *dev, void *data));
extern struct device *
iscsi_find_flashnode_conn(struct iscsi_bus_flash_session *fnode_sess);
extern char *
iscsi_get_ipaddress_state_name(enum iscsi_ipaddress_state port_state);
extern char *iscsi_get_router_state_name(enum iscsi_router_state router_state);
#endif
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