iscsi-target: Drop legacy iscsi_target_tq.c logic

Now that iscsi_conn allocates new [rx,tx] threads using kthread.h
primitives on the fly, and kthread_stop() is called directly during
connection shutdown, it's time to go ahead and drop iscsi_target_tq.c
legacy code.

The use of multiple struct completion in iscsi_activate_thread_set()
has been proven to cause issues during repeated iser login/logout.
Tested-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Slava Shwartsman <valyushash@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/Makefile

 iscsi_target_mod-y +=		iscsi_target_parameters.o \
 				iscsi_target_seq_pdu_list.o \
-				iscsi_target_tq.o \
 				iscsi_target_auth.o \
 				iscsi_target_datain_values.o \
 				iscsi_target_device.o \

drivers/target/iscsi/iscsi_target.c

@@ -33,7 +33,6 @@
 #include <target/iscsi/iscsi_target_core.h>
 #include "iscsi_target_parameters.h"
 #include "iscsi_target_seq_pdu_list.h"
-#include "iscsi_target_tq.h"
 #include "iscsi_target_configfs.h"
 #include "iscsi_target_datain_values.h"
 #include "iscsi_target_erl0.h"
@@ -4360,8 +4359,6 @@ int iscsit_close_connection(
 
 	iscsit_put_transport(conn->conn_transport);
 
-	conn->thread_set = NULL;
-
 	pr_debug("Moving to TARG_CONN_STATE_FREE.\n");
 	conn->conn_state = TARG_CONN_STATE_FREE;
 	kfree(conn);

drivers/target/iscsi/iscsi_target_erl0.c

@@ -24,7 +24,6 @@
 #include <target/iscsi/iscsi_target_core.h>
 #include <target/iscsi/iscsi_transport.h>
 #include "iscsi_target_seq_pdu_list.h"
-#include "iscsi_target_tq.h"
 #include "iscsi_target_erl0.h"
 #include "iscsi_target_erl1.h"
 #include "iscsi_target_erl2.h"

drivers/target/iscsi/iscsi_target_login.c

@@ -26,7 +26,6 @@
 
 #include <target/iscsi/iscsi_target_core.h>
 #include <target/iscsi/iscsi_target_stat.h>
-#include "iscsi_target_tq.h"
 #include "iscsi_target_device.h"
 #include "iscsi_target_nego.h"
 #include "iscsi_target_erl0.h"

drivers/target/iscsi/iscsi_target_tq.h

-#ifndef ISCSI_THREAD_QUEUE_H
-#define ISCSI_THREAD_QUEUE_H
-
-/*
- * Defines for thread sets.
- */
-extern int iscsi_thread_set_force_reinstatement(struct iscsi_conn *);
-extern int iscsi_allocate_thread_sets(u32);
-extern void iscsi_deallocate_thread_sets(void);
-extern void iscsi_activate_thread_set(struct iscsi_conn *, struct iscsi_thread_set *);
-extern struct iscsi_thread_set *iscsi_get_thread_set(void);
-extern void iscsi_set_thread_clear(struct iscsi_conn *, u8);
-extern void iscsi_set_thread_set_signal(struct iscsi_conn *, u8);
-extern int iscsi_release_thread_set(struct iscsi_conn *);
-extern struct iscsi_conn *iscsi_rx_thread_pre_handler(struct iscsi_thread_set *);
-extern struct iscsi_conn *iscsi_tx_thread_pre_handler(struct iscsi_thread_set *);
-extern int iscsi_thread_set_init(void);
-extern void iscsi_thread_set_free(void);
-
-extern int iscsi_target_tx_thread(void *);
-extern int iscsi_target_rx_thread(void *);
-
-#define TARGET_THREAD_SET_COUNT			4
-
-#define ISCSI_RX_THREAD                         1
-#define ISCSI_TX_THREAD                         2
-#define ISCSI_RX_THREAD_NAME			"iscsi_trx"
-#define ISCSI_TX_THREAD_NAME			"iscsi_ttx"
-#define ISCSI_BLOCK_RX_THREAD			0x1
-#define ISCSI_BLOCK_TX_THREAD			0x2
-#define ISCSI_CLEAR_RX_THREAD			0x1
-#define ISCSI_CLEAR_TX_THREAD			0x2
-#define ISCSI_SIGNAL_RX_THREAD			0x1
-#define ISCSI_SIGNAL_TX_THREAD			0x2
-
-/* struct iscsi_thread_set->status */
-#define ISCSI_THREAD_SET_FREE			1
-#define ISCSI_THREAD_SET_ACTIVE			2
-#define ISCSI_THREAD_SET_DIE			3
-#define ISCSI_THREAD_SET_RESET			4
-#define ISCSI_THREAD_SET_DEALLOCATE_THREADS	5
-
-/* By default allow a maximum of 32K iSCSI connections */
-#define ISCSI_TS_BITMAP_BITS			32768
-
-struct iscsi_thread_set {
-	/* flags used for blocking and restarting sets */
-	int	blocked_threads;
-	/* flag for creating threads */
-	int	create_threads;
-	/* flag for delaying readding to inactive list */
-	int	delay_inactive;
-	/* status for thread set */
-	int	status;
-	/* which threads have had signals sent */
-	int	signal_sent;
-	/* flag for which threads exited first */
-	int	thread_clear;
-	/* Active threads in the thread set */
-	int	thread_count;
-	/* Unique thread ID */
-	u32	thread_id;
-	/* pointer to connection if set is active */
-	struct iscsi_conn	*conn;
-	/* used for controlling ts state accesses */
-	spinlock_t	ts_state_lock;
-	/* used for restarting thread queue */
-	struct completion	rx_restart_comp;
-	/* used for restarting thread queue */
-	struct completion	tx_restart_comp;
-	/* used for normal unused blocking */
-	struct completion	rx_start_comp;
-	/* used for normal unused blocking */
-	struct completion	tx_start_comp;
-	/* OS descriptor for rx thread */
-	struct task_struct	*rx_thread;
-	/* OS descriptor for tx thread */
-	struct task_struct	*tx_thread;
-	/* struct iscsi_thread_set in list list head*/
-	struct list_head	ts_list;
-	struct semaphore	ts_activate_sem;
-};
-
-#endif   /*** ISCSI_THREAD_QUEUE_H ***/

drivers/target/iscsi/iscsi_target_util.c

@@ -33,7 +33,6 @@
 #include "iscsi_target_erl1.h"
 #include "iscsi_target_erl2.h"
 #include "iscsi_target_tpg.h"
-#include "iscsi_target_tq.h"
 #include "iscsi_target_util.h"
 #include "iscsi_target.h"
 

include/target/iscsi/iscsi_target_core.h

@@ -20,6 +20,8 @@
 #define ISCSIT_MIN_TAGS			16
 #define ISCSIT_EXTRA_TAGS		8
 #define ISCSIT_TCP_BACKLOG		256
+#define ISCSI_RX_THREAD_NAME		"iscsi_trx"
+#define ISCSI_TX_THREAD_NAME		"iscsi_ttx"
 
 /* struct iscsi_node_attrib sanity values */
 #define NA_DATAOUT_TIMEOUT		3
@@ -600,8 +602,6 @@ struct iscsi_conn {
 	struct iscsi_tpg_np	*tpg_np;
 	/* Pointer to parent session */
 	struct iscsi_session	*sess;
-	/* Pointer to thread_set in use for this conn's threads */
-	struct iscsi_thread_set	*thread_set;
 	int			bitmap_id;
 	int			rx_thread_active;
 	struct task_struct	*rx_thread;
@@ -877,8 +877,6 @@ struct iscsit_global {
 	u32			auth_id;
 	u32			inactive_ts;
 #define ISCSIT_BITMAP_BITS	262144
-	/* Thread Set bitmap count */
-	int			ts_bitmap_count;
 	/* Thread Set bitmap pointer */
 	unsigned long		*ts_bitmap;
 	spinlock_t		ts_bitmap_lock;