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linux-next/include/target/target_core_fabric_ops.h
Nicholas Bellinger a17f091d1a target: Add generic active I/O shutdown logic
This patch adds the initial pieces of generic active I/O shutdown logic.
This is intended to be a 'opt-in' feature for fabric modules that
includes the following functions to provide a mechinism for fabric
modules to track se_cmd via se_session->sess_cmd_list:

*) target_get_sess_cmd() - Add se_cmd to sess->sess_cmd_list, called
   from fabric module incoming I/O path.
*) target_put_sess_cmd() - Check for completion or drop se_cmd from
   ->sess_cmd_list
*) target_splice_sess_cmd_list() - Splice active I/O list from
   ->sess_cmd_list to ->sess_wait_list, can called with HW fabric
   lock held.
*) target_wait_for_sess_cmds() - Walk ->sess_wait_list waiting on
   individual ->cmd_wait_comp.  Optional transport_wait_for_tasks()
   call.

target_splice_sess_cmd_list() is allowed to be called under HW fabric
lock, and performs the splice into se_sess->sess_wait_list and set
se_cmd->cmd_wait_set.  Then target_wait_for_sess_cmds() walks the list
waiting for individual target_put_sess_cmd() fabric callbacks to
complete.

It also adds TFO->check_release_cmd() to split the completion and memory
release calls, where a fabric module uses target_put_sess_cmd() to check
for I/O completion during session shutdown.  This is currently pushed out
into fabric modules as current fabric code may sleep here waiting for
TFO->check_stop_free() to complete in main response path, and because
target_wait_for_sess_cmds() calling TFO->release_cmd() to free fabric
descriptor memory directly.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-11-04 07:50:26 +00:00

106 lines
4.1 KiB
C

/* Defined in target_core_configfs.h */
struct target_fabric_configfs;
struct target_core_fabric_ops {
struct configfs_subsystem *tf_subsys;
/*
* Optional to signal struct se_task->task_sg[] padding entries
* for scatterlist chaining using transport_do_task_sg_link(),
* disabled by default
*/
bool task_sg_chaining;
char *(*get_fabric_name)(void);
u8 (*get_fabric_proto_ident)(struct se_portal_group *);
char *(*tpg_get_wwn)(struct se_portal_group *);
u16 (*tpg_get_tag)(struct se_portal_group *);
u32 (*tpg_get_default_depth)(struct se_portal_group *);
u32 (*tpg_get_pr_transport_id)(struct se_portal_group *,
struct se_node_acl *,
struct t10_pr_registration *, int *,
unsigned char *);
u32 (*tpg_get_pr_transport_id_len)(struct se_portal_group *,
struct se_node_acl *,
struct t10_pr_registration *, int *);
char *(*tpg_parse_pr_out_transport_id)(struct se_portal_group *,
const char *, u32 *, char **);
int (*tpg_check_demo_mode)(struct se_portal_group *);
int (*tpg_check_demo_mode_cache)(struct se_portal_group *);
int (*tpg_check_demo_mode_write_protect)(struct se_portal_group *);
int (*tpg_check_prod_mode_write_protect)(struct se_portal_group *);
/*
* Optionally used by fabrics to allow demo-mode login, but not
* expose any TPG LUNs, and return 'not connected' in standard
* inquiry response
*/
int (*tpg_check_demo_mode_login_only)(struct se_portal_group *);
struct se_node_acl *(*tpg_alloc_fabric_acl)(
struct se_portal_group *);
void (*tpg_release_fabric_acl)(struct se_portal_group *,
struct se_node_acl *);
u32 (*tpg_get_inst_index)(struct se_portal_group *);
/*
* Optional function pointer for TCM to perform command map
* from TCM processing thread context, for those struct se_cmd
* initially allocated in interrupt context.
*/
int (*new_cmd_map)(struct se_cmd *);
/*
* Optional to release struct se_cmd and fabric dependent allocated
* I/O descriptor in transport_cmd_check_stop().
*
* Returning 1 will signal a descriptor has been released.
* Returning 0 will signal a descriptor has not been released.
*/
int (*check_stop_free)(struct se_cmd *);
/*
* Optional check for active I/O shutdown
*/
int (*check_release_cmd)(struct se_cmd *);
void (*release_cmd)(struct se_cmd *);
/*
* Called with spin_lock_bh(struct se_portal_group->session_lock held.
*/
int (*shutdown_session)(struct se_session *);
void (*close_session)(struct se_session *);
void (*stop_session)(struct se_session *, int, int);
void (*fall_back_to_erl0)(struct se_session *);
int (*sess_logged_in)(struct se_session *);
u32 (*sess_get_index)(struct se_session *);
/*
* Used only for SCSI fabrics that contain multi-value TransportIDs
* (like iSCSI). All other SCSI fabrics should set this to NULL.
*/
u32 (*sess_get_initiator_sid)(struct se_session *,
unsigned char *, u32);
int (*write_pending)(struct se_cmd *);
int (*write_pending_status)(struct se_cmd *);
void (*set_default_node_attributes)(struct se_node_acl *);
u32 (*get_task_tag)(struct se_cmd *);
int (*get_cmd_state)(struct se_cmd *);
int (*queue_data_in)(struct se_cmd *);
int (*queue_status)(struct se_cmd *);
int (*queue_tm_rsp)(struct se_cmd *);
u16 (*set_fabric_sense_len)(struct se_cmd *, u32);
u16 (*get_fabric_sense_len)(void);
int (*is_state_remove)(struct se_cmd *);
/*
* fabric module calls for target_core_fabric_configfs.c
*/
struct se_wwn *(*fabric_make_wwn)(struct target_fabric_configfs *,
struct config_group *, const char *);
void (*fabric_drop_wwn)(struct se_wwn *);
struct se_portal_group *(*fabric_make_tpg)(struct se_wwn *,
struct config_group *, const char *);
void (*fabric_drop_tpg)(struct se_portal_group *);
int (*fabric_post_link)(struct se_portal_group *,
struct se_lun *);
void (*fabric_pre_unlink)(struct se_portal_group *,
struct se_lun *);
struct se_tpg_np *(*fabric_make_np)(struct se_portal_group *,
struct config_group *, const char *);
void (*fabric_drop_np)(struct se_tpg_np *);
struct se_node_acl *(*fabric_make_nodeacl)(struct se_portal_group *,
struct config_group *, const char *);
void (*fabric_drop_nodeacl)(struct se_node_acl *);
};