Re: [PATCH][RFC 6/12/1/5] SCST core's private header

[Vladislav Bolkhovitin <vst@vlnb.net>]

This patch contains file scst_priv.h, which contains internal SCST types, constants
and declarations.

Signed-off-by: Vladislav Bolkhovitin <vst@vlnb.net>
---
 scst_priv.h |  609 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 609 insertions(+)

diff -uprN orig/linux-2.6.33/drivers/scst/scst_priv.h linux-2.6.33/drivers/scst/scst_priv.h
--- orig/linux-2.6.33/drivers/scst/scst_priv.h
+++ linux-2.6.33/drivers/scst/scst_priv.h
@@ -0,0 +1,609 @@
+/*
+ *  scst_priv.h
+ *
+ *  Copyright (C) 2004 - 2010 Vladislav Bolkhovitin <vst@vlnb.net>
+ *  Copyright (C) 2004 - 2005 Leonid Stoljar
+ *  Copyright (C) 2007 - 2010 ID7 Ltd.
+ *
+ *  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, version 2
+ *  of the License.
+ *
+ *  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.
+ */
+
+#ifndef __SCST_PRIV_H
+#define __SCST_PRIV_H
+
+#include <linux/types.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+
+#define LOG_PREFIX "scst"
+
+#include "scst_debug.h"
+
+#define TRACE_RTRY              0x80000000
+#define TRACE_SCSI_SERIALIZING  0x40000000
+/** top being the edge away from the interupt */
+#define TRACE_SND_TOP		0x20000000
+#define TRACE_RCV_TOP		0x01000000
+/** bottom being the edge toward the interupt */
+#define TRACE_SND_BOT		0x08000000
+#define TRACE_RCV_BOT		0x04000000
+
+#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
+#define trace_flag scst_trace_flag
+extern unsigned long scst_trace_flag;
+#endif
+
+#ifdef CONFIG_SCST_DEBUG
+
+#define SCST_DEFAULT_LOG_FLAGS (TRACE_OUT_OF_MEM | TRACE_MINOR | TRACE_PID | \
+	TRACE_LINE | TRACE_FUNCTION | TRACE_SPECIAL | TRACE_MGMT | \
+	TRACE_MGMT_DEBUG | TRACE_RTRY)
+
+#define TRACE_RETRY(args...)	TRACE_DBG_FLAG(TRACE_RTRY, args)
+#define TRACE_SN(args...)	TRACE_DBG_FLAG(TRACE_SCSI_SERIALIZING, args)
+#define TRACE_SEND_TOP(args...)	TRACE_DBG_FLAG(TRACE_SND_TOP, args)
+#define TRACE_RECV_TOP(args...)	TRACE_DBG_FLAG(TRACE_RCV_TOP, args)
+#define TRACE_SEND_BOT(args...)	TRACE_DBG_FLAG(TRACE_SND_BOT, args)
+#define TRACE_RECV_BOT(args...)	TRACE_DBG_FLAG(TRACE_RCV_BOT, args)
+
+#else /* CONFIG_SCST_DEBUG */
+
+# ifdef CONFIG_SCST_TRACING
+#define SCST_DEFAULT_LOG_FLAGS (TRACE_OUT_OF_MEM | TRACE_MGMT | \
+	TRACE_SPECIAL)
+# else
+#define SCST_DEFAULT_LOG_FLAGS 0
+# endif
+
+#define TRACE_RETRY(args...)
+#define TRACE_SN(args...)
+#define TRACE_SEND_TOP(args...)
+#define TRACE_RECV_TOP(args...)
+#define TRACE_SEND_BOT(args...)
+#define TRACE_RECV_BOT(args...)
+
+#endif
+
+/**
+ ** Bits for scst_flags
+ **/
+
+/*
+ * Set if new commands initialization is being suspended for a while.
+ * Used to let TM commands execute while preparing the suspend, since
+ * RESET or ABORT could be necessary to free SCSI commands.
+ */
+#define SCST_FLAG_SUSPENDING		     0
+
+/* Set if new commands initialization is suspended for a while */
+#define SCST_FLAG_SUSPENDED		     1
+
+/**
+ ** Return codes for cmd state process functions. Codes are the same as
+ ** for SCST_EXEC_* to avoid translation to them and, hence, have better code.
+ **/
+#define SCST_CMD_STATE_RES_CONT_NEXT         SCST_EXEC_COMPLETED
+#define SCST_CMD_STATE_RES_CONT_SAME         SCST_EXEC_NOT_COMPLETED
+#define SCST_CMD_STATE_RES_NEED_THREAD       SCST_EXEC_NEED_THREAD
+
+/**
+ ** Maximum count of uncompleted commands that an initiator could
+ ** queue on any device. Then it will start getting TASK QUEUE FULL status.
+ **/
+#define SCST_MAX_TGT_DEV_COMMANDS            48
+
+/**
+ ** Maximum count of uncompleted commands that could be queued on any device.
+ ** Then initiators sending commands to this device will start getting
+ ** TASK QUEUE FULL status.
+ **/
+#define SCST_MAX_DEV_COMMANDS                256
+
+#define SCST_TGT_RETRY_TIMEOUT               (3/2*HZ)
+
+/* Definitions of symbolic constants for LUN addressing method */
+#define SCST_LUN_ADDR_METHOD_PERIPHERAL	0
+#define SCST_LUN_ADDR_METHOD_FLAT 	1
+
+extern int scst_threads;
+
+extern unsigned int scst_max_dev_cmd_mem;
+
+extern mempool_t *scst_mgmt_mempool;
+extern mempool_t *scst_mgmt_stub_mempool;
+extern mempool_t *scst_ua_mempool;
+extern mempool_t *scst_sense_mempool;
+extern mempool_t *scst_aen_mempool;
+
+extern struct kmem_cache *scst_cmd_cachep;
+extern struct kmem_cache *scst_sess_cachep;
+extern struct kmem_cache *scst_tgtd_cachep;
+extern struct kmem_cache *scst_acgd_cachep;
+
+extern spinlock_t scst_main_lock;
+
+extern struct scst_sgv_pools scst_sgv;
+
+extern unsigned long scst_flags;
+extern atomic_t scst_cmd_count;
+extern struct list_head scst_template_list;
+extern struct list_head scst_dev_list;
+extern struct list_head scst_dev_type_list;
+extern wait_queue_head_t scst_dev_cmd_waitQ;
+
+extern unsigned int scst_setup_id;
+
+extern spinlock_t scst_init_lock;
+extern struct list_head scst_init_cmd_list;
+extern wait_queue_head_t scst_init_cmd_list_waitQ;
+extern unsigned int scst_init_poll_cnt;
+
+extern struct scst_cmd_threads scst_main_cmd_threads;
+
+extern spinlock_t scst_mcmd_lock;
+/* The following lists protected by scst_mcmd_lock */
+extern struct list_head scst_active_mgmt_cmd_list;
+extern struct list_head scst_delayed_mgmt_cmd_list;
+extern wait_queue_head_t scst_mgmt_cmd_list_waitQ;
+
+struct scst_tasklet {
+	spinlock_t tasklet_lock;
+	struct list_head tasklet_cmd_list;
+	struct tasklet_struct tasklet;
+};
+extern struct scst_tasklet scst_tasklets[NR_CPUS];
+
+extern wait_queue_head_t scst_mgmt_waitQ;
+extern spinlock_t scst_mgmt_lock;
+extern struct list_head scst_sess_init_list;
+extern struct list_head scst_sess_shut_list;
+
+struct scst_cmd_thread_t {
+	struct task_struct *cmd_thread;
+	struct list_head thread_list_entry;
+};
+
+static inline bool scst_set_io_context(struct scst_cmd *cmd,
+	struct io_context **old)
+{
+	bool res;
+
+	if (cmd->cmd_threads == &scst_main_cmd_threads) {
+		EXTRACHECKS_BUG_ON(in_interrupt());
+		/*
+		 * No need for any ref counting action, because io_context
+		 * supposed to be cleared in the end of the caller function.
+		 */
+		current->io_context = cmd->tgt_dev->async_io_context;
+		res = true;
+		TRACE_DBG("io_context %p (tgt_dev %p)", current->io_context,
+			cmd->tgt_dev);
+		EXTRACHECKS_BUG_ON(current->io_context == NULL);
+	} else
+		res = false;
+
+	return res;
+}
+
+static inline void scst_reset_io_context(struct scst_tgt_dev *tgt_dev,
+	struct io_context *old)
+{
+	current->io_context = old;
+	TRACE_DBG("io_context %p reset", current->io_context);
+	return;
+}
+
+/*
+ * Converts string presentation of threads pool type to enum.
+ * Returns SCST_THREADS_POOL_TYPE_INVALID if the string is invalid.
+ */
+extern enum scst_dev_type_threads_pool_type scst_parse_threads_pool_type(
+	const char *p, int len);
+
+extern int scst_add_threads(struct scst_cmd_threads *cmd_threads,
+	struct scst_device *dev, struct scst_tgt_dev *tgt_dev, int num);
+extern void scst_del_threads(struct scst_cmd_threads *cmd_threads, int num);
+
+extern int scst_create_dev_threads(struct scst_device *dev);
+extern void scst_stop_dev_threads(struct scst_device *dev);
+
+extern int scst_tgt_dev_setup_threads(struct scst_tgt_dev *tgt_dev);
+extern void scst_tgt_dev_stop_threads(struct scst_tgt_dev *tgt_dev);
+
+extern bool scst_del_thr_data(struct scst_tgt_dev *tgt_dev,
+	struct task_struct *tsk);
+
+extern struct scst_dev_type scst_null_devtype;
+
+extern struct scst_cmd *__scst_check_deferred_commands(
+	struct scst_tgt_dev *tgt_dev);
+
+/* Used to save the function call on the fast path */
+static inline struct scst_cmd *scst_check_deferred_commands(
+	struct scst_tgt_dev *tgt_dev)
+{
+	if (tgt_dev->def_cmd_count == 0)
+		return NULL;
+	else
+		return __scst_check_deferred_commands(tgt_dev);
+}
+
+static inline void scst_make_deferred_commands_active(
+	struct scst_tgt_dev *tgt_dev)
+{
+	struct scst_cmd *c;
+
+	c = __scst_check_deferred_commands(tgt_dev);
+	if (c != NULL) {
+		TRACE_SN("Adding cmd %p to active cmd list", c);
+		spin_lock_irq(&c->cmd_threads->cmd_list_lock);
+		list_add_tail(&c->cmd_list_entry,
+			&c->cmd_threads->active_cmd_list);
+		wake_up(&c->cmd_threads->cmd_list_waitQ);
+		spin_unlock_irq(&c->cmd_threads->cmd_list_lock);
+	}
+
+	return;
+}
+
+void scst_inc_expected_sn(struct scst_tgt_dev *tgt_dev, atomic_t *slot);
+int scst_check_hq_cmd(struct scst_cmd *cmd);
+
+void scst_unblock_deferred(struct scst_tgt_dev *tgt_dev,
+	struct scst_cmd *cmd_sn);
+
+void scst_on_hq_cmd_response(struct scst_cmd *cmd);
+void scst_xmit_process_aborted_cmd(struct scst_cmd *cmd);
+
+int scst_cmd_thread(void *arg);
+void scst_cmd_tasklet(long p);
+int scst_init_thread(void *arg);
+int scst_tm_thread(void *arg);
+int scst_global_mgmt_thread(void *arg);
+
+int scst_queue_retry_cmd(struct scst_cmd *cmd, int finished_cmds);
+
+static inline void scst_tgtt_cleanup(struct scst_tgt_template *tgtt) { }
+static inline void scst_devt_cleanup(struct scst_dev_type *devt) { }
+
+int scst_alloc_tgt(struct scst_tgt_template *tgtt, struct scst_tgt **tgt);
+void scst_free_tgt(struct scst_tgt *tgt);
+
+int scst_alloc_device(gfp_t gfp_mask, struct scst_device **out_dev);
+void scst_free_device(struct scst_device *dev);
+
+struct scst_acg *scst_alloc_add_acg(struct scst_tgt *tgt,
+	const char *acg_name);
+void scst_clear_acg(struct scst_acg *acg);
+void scst_destroy_acg(struct scst_acg *acg);
+void scst_free_acg(struct scst_acg *acg);
+
+struct scst_acg *scst_tgt_find_acg(struct scst_tgt *tgt, const char *name);
+
+struct scst_acg *scst_find_acg(const struct scst_session *sess);
+
+void scst_check_reassign_sessions(void);
+
+int scst_sess_alloc_tgt_devs(struct scst_session *sess);
+void scst_sess_free_tgt_devs(struct scst_session *sess);
+void scst_nexus_loss(struct scst_tgt_dev *tgt_dev, bool queue_UA);
+
+int scst_acg_add_dev(struct scst_acg *acg, struct scst_device *dev,
+	uint64_t lun, int read_only, bool gen_scst_report_luns_changed);
+int scst_acg_remove_dev(struct scst_acg *acg, struct scst_device *dev,
+	bool gen_scst_report_luns_changed);
+
+void scst_acg_dev_destroy(struct scst_acg_dev *acg_dev);
+
+int scst_acg_add_name(struct scst_acg *acg, const char *name);
+void scst_acg_remove_acn(struct scst_acn *acn);
+struct scst_acn *scst_acg_find_name(struct scst_acg *acg, const char *name);
+
+/* The activity supposed to be suspended and scst_mutex held */
+static inline bool scst_acg_sess_is_empty(struct scst_acg *acg)
+{
+	return list_empty(&acg->acg_sess_list);
+}
+
+int scst_prepare_request_sense(struct scst_cmd *orig_cmd);
+int scst_finish_internal_cmd(struct scst_cmd *cmd);
+
+void scst_store_sense(struct scst_cmd *cmd);
+
+int scst_assign_dev_handler(struct scst_device *dev,
+	struct scst_dev_type *handler);
+
+struct scst_session *scst_alloc_session(struct scst_tgt *tgt, gfp_t gfp_mask,
+	const char *initiator_name);
+void scst_free_session(struct scst_session *sess);
+void scst_release_session(struct scst_session *sess);
+void scst_free_session_callback(struct scst_session *sess);
+
+struct scst_cmd *scst_alloc_cmd(gfp_t gfp_mask);
+void scst_free_cmd(struct scst_cmd *cmd);
+static inline void scst_destroy_cmd(struct scst_cmd *cmd)
+{
+	kmem_cache_free(scst_cmd_cachep, cmd);
+	return;
+}
+
+void scst_check_retries(struct scst_tgt *tgt);
+
+int scst_scsi_exec_async(struct scst_cmd *cmd,
+	void (*done)(void *, char *, int, int));
+
+int scst_alloc_space(struct scst_cmd *cmd);
+
+int scst_lib_init(void);
+void scst_lib_exit(void);
+
+uint64_t scst_pack_lun(const uint64_t lun, unsigned int addr_method);
+uint64_t scst_unpack_lun(const uint8_t *lun, int len);
+
+struct scst_mgmt_cmd *scst_alloc_mgmt_cmd(gfp_t gfp_mask);
+void scst_free_mgmt_cmd(struct scst_mgmt_cmd *mcmd);
+void scst_done_cmd_mgmt(struct scst_cmd *cmd);
+
+int scst_sysfs_init(void);
+void scst_sysfs_cleanup(void);
+int scst_create_tgtt_sysfs(struct scst_tgt_template *tgtt);
+void scst_tgtt_sysfs_put(struct scst_tgt_template *tgtt);
+int scst_create_tgt_sysfs(struct scst_tgt *tgt);
+void scst_tgt_sysfs_prepare_put(struct scst_tgt *tgt);
+void scst_tgt_sysfs_put(struct scst_tgt *tgt);
+int scst_create_sess_sysfs(struct scst_session *sess);
+void scst_sess_sysfs_put(struct scst_session *sess);
+int scst_create_sgv_sysfs(struct sgv_pool *pool);
+void scst_sgv_sysfs_put(struct sgv_pool *pool);
+int scst_create_devt_sysfs(struct scst_dev_type *devt);
+void scst_devt_sysfs_put(struct scst_dev_type *devt);
+int scst_create_device_sysfs(struct scst_device *dev);
+void scst_device_sysfs_put(struct scst_device *dev);
+int scst_create_devt_dev_sysfs(struct scst_device *dev);
+void scst_devt_dev_sysfs_put(struct scst_device *dev);
+int scst_create_acn_sysfs(struct scst_acg *acg, struct scst_acn *acn);
+void scst_acn_sysfs_del(struct scst_acg *acg, struct scst_acn *acn,
+	bool reassign);
+
+void scst_acg_sysfs_put(struct scst_acg *acg);
+
+int scst_get_cdb_len(const uint8_t *cdb);
+
+void __scst_dev_check_set_UA(struct scst_device *dev, struct scst_cmd *exclude,
+	const uint8_t *sense, int sense_len);
+static inline void scst_dev_check_set_UA(struct scst_device *dev,
+	struct scst_cmd *exclude, const uint8_t *sense, int sense_len)
+{
+	spin_lock_bh(&dev->dev_lock);
+	__scst_dev_check_set_UA(dev, exclude, sense, sense_len);
+	spin_unlock_bh(&dev->dev_lock);
+	return;
+}
+void scst_dev_check_set_local_UA(struct scst_device *dev,
+	struct scst_cmd *exclude, const uint8_t *sense, int sense_len);
+
+#define SCST_SET_UA_FLAG_AT_HEAD	1
+#define SCST_SET_UA_FLAG_GLOBAL		2
+
+void scst_check_set_UA(struct scst_tgt_dev *tgt_dev,
+	const uint8_t *sense, int sense_len, int flags);
+int scst_set_pending_UA(struct scst_cmd *cmd);
+
+void scst_report_luns_changed(struct scst_acg *acg);
+
+void scst_abort_cmd(struct scst_cmd *cmd, struct scst_mgmt_cmd *mcmd,
+	int other_ini, int call_dev_task_mgmt_fn);
+void scst_process_reset(struct scst_device *dev,
+	struct scst_session *originator, struct scst_cmd *exclude_cmd,
+	struct scst_mgmt_cmd *mcmd, bool setUA);
+
+bool scst_is_ua_global(const uint8_t *sense, int len);
+void scst_requeue_ua(struct scst_cmd *cmd);
+
+void scst_gen_aen_or_ua(struct scst_tgt_dev *tgt_dev,
+	int key, int asc, int ascq);
+
+static inline bool scst_is_implicit_hq(struct scst_cmd *cmd)
+{
+	return (cmd->op_flags & SCST_IMPLICIT_HQ) != 0;
+}
+
+/*
+ * Some notes on devices "blocking". Blocking means that no
+ * commands will go from SCST to underlying SCSI device until it
+ * is unblocked. But we don't care about all commands that
+ * already on the device.
+ */
+
+extern int scst_inc_on_dev_cmd(struct scst_cmd *cmd);
+
+extern void __scst_block_dev(struct scst_device *dev);
+extern void scst_block_dev_cmd(struct scst_cmd *cmd, int outstanding);
+extern void scst_unblock_dev(struct scst_device *dev);
+extern void scst_unblock_dev_cmd(struct scst_cmd *cmd);
+
+/* No locks */
+static inline void scst_dec_on_dev_cmd(struct scst_cmd *cmd)
+{
+	struct scst_device *dev = cmd->dev;
+	bool unblock_dev = cmd->inc_blocking;
+
+	if (cmd->inc_blocking) {
+		TRACE_MGMT_DBG("cmd %p (tag %llu): unblocking dev %p", cmd,
+			       (long long unsigned int)cmd->tag, cmd->dev);
+		cmd->inc_blocking = 0;
+	}
+	cmd->dec_on_dev_needed = 0;
+
+	if (unblock_dev)
+		scst_unblock_dev(dev);
+
+	atomic_dec(&dev->on_dev_count);
+	/* See comment in scst_block_dev() */
+	smp_mb__after_atomic_dec();
+
+	TRACE_DBG("New on_dev_count %d", atomic_read(&dev->on_dev_count));
+
+	BUG_ON(atomic_read(&dev->on_dev_count) < 0);
+
+	if (unlikely(dev->block_count != 0))
+		wake_up_all(&dev->on_dev_waitQ);
+
+	return;
+}
+
+static inline void __scst_get(int barrier)
+{
+	atomic_inc(&scst_cmd_count);
+	TRACE_DBG("Incrementing scst_cmd_count(new value %d)",
+		atomic_read(&scst_cmd_count));
+
+	/* See comment about smp_mb() in scst_suspend_activity() */
+	if (barrier)
+		smp_mb__after_atomic_inc();
+}
+
+static inline void __scst_put(void)
+{
+	int f;
+	f = atomic_dec_and_test(&scst_cmd_count);
+	/* See comment about smp_mb() in scst_suspend_activity() */
+	if (f && unlikely(test_bit(SCST_FLAG_SUSPENDED, &scst_flags))) {
+		TRACE_MGMT_DBG("%s", "Waking up scst_dev_cmd_waitQ");
+		wake_up_all(&scst_dev_cmd_waitQ);
+	}
+	TRACE_DBG("Decrementing scst_cmd_count(new value %d)",
+	      atomic_read(&scst_cmd_count));
+}
+
+void scst_sched_session_free(struct scst_session *sess);
+
+static inline void scst_sess_get(struct scst_session *sess)
+{
+	atomic_inc(&sess->refcnt);
+	TRACE_DBG("Incrementing sess %p refcnt (new value %d)",
+		sess, atomic_read(&sess->refcnt));
+}
+
+static inline void scst_sess_put(struct scst_session *sess)
+{
+	TRACE_DBG("Decrementing sess %p refcnt (new value %d)",
+		sess, atomic_read(&sess->refcnt)-1);
+	if (atomic_dec_and_test(&sess->refcnt))
+		scst_sched_session_free(sess);
+}
+
+static inline void __scst_cmd_get(struct scst_cmd *cmd)
+{
+	atomic_inc(&cmd->cmd_ref);
+	TRACE_DBG("Incrementing cmd %p ref (new value %d)",
+		cmd, atomic_read(&cmd->cmd_ref));
+}
+
+static inline void __scst_cmd_put(struct scst_cmd *cmd)
+{
+	TRACE_DBG("Decrementing cmd %p ref (new value %d)",
+		cmd, atomic_read(&cmd->cmd_ref)-1);
+	if (atomic_dec_and_test(&cmd->cmd_ref))
+		scst_free_cmd(cmd);
+}
+
+extern void scst_throttle_cmd(struct scst_cmd *cmd);
+extern void scst_unthrottle_cmd(struct scst_cmd *cmd);
+
+static inline void scst_check_restore_sg_buff(struct scst_cmd *cmd)
+{
+	if (cmd->sg_buff_modified) {
+		TRACE_MEM("cmd %p, sg %p, orig_sg_entry %d, "
+			"orig_entry_len %d, orig_sg_cnt %d", cmd, cmd->sg,
+			cmd->orig_sg_entry, cmd->orig_entry_len,
+			cmd->orig_sg_cnt);
+		cmd->sg[cmd->orig_sg_entry].length = cmd->orig_entry_len;
+		cmd->sg_cnt = cmd->orig_sg_cnt;
+		cmd->sg_buff_modified = 0;
+	}
+}
+
+#ifdef CONFIG_SCST_DEBUG_TM
+extern void tm_dbg_check_released_cmds(void);
+extern int tm_dbg_check_cmd(struct scst_cmd *cmd);
+extern void tm_dbg_release_cmd(struct scst_cmd *cmd);
+extern void tm_dbg_task_mgmt(struct scst_device *dev, const char *fn,
+	int force);
+extern int tm_dbg_is_release(void);
+#else
+static inline void tm_dbg_check_released_cmds(void) {}
+static inline int tm_dbg_check_cmd(struct scst_cmd *cmd)
+{
+	return 0;
+}
+static inline void tm_dbg_release_cmd(struct scst_cmd *cmd) {}
+static inline void tm_dbg_task_mgmt(struct scst_device *dev, const char *fn,
+	int force) {}
+static inline int tm_dbg_is_release(void)
+{
+	return 0;
+}
+#endif /* CONFIG_SCST_DEBUG_TM */
+
+#ifdef CONFIG_SCST_DEBUG_SN
+void scst_check_debug_sn(struct scst_cmd *cmd);
+#else
+static inline void scst_check_debug_sn(struct scst_cmd *cmd) {}
+#endif
+
+static inline int scst_sn_before(uint32_t seq1, uint32_t seq2)
+{
+	return (int32_t)(seq1-seq2) < 0;
+}
+
+bool scst_is_relative_target_port_id_unique(uint16_t id, struct scst_tgt *t);
+int gen_relative_target_port_id(uint16_t *id);
+
+#ifdef CONFIG_SCST_MEASURE_LATENCY
+
+void scst_set_start_time(struct scst_cmd *cmd);
+void scst_set_cur_start(struct scst_cmd *cmd);
+void scst_set_parse_time(struct scst_cmd *cmd);
+void scst_set_alloc_buf_time(struct scst_cmd *cmd);
+void scst_set_restart_waiting_time(struct scst_cmd *cmd);
+void scst_set_rdy_to_xfer_time(struct scst_cmd *cmd);
+void scst_set_pre_exec_time(struct scst_cmd *cmd);
+void scst_set_exec_time(struct scst_cmd *cmd);
+void scst_set_dev_done_time(struct scst_cmd *cmd);
+void scst_set_xmit_time(struct scst_cmd *cmd);
+void scst_set_tgt_on_free_time(struct scst_cmd *cmd);
+void scst_set_dev_on_free_time(struct scst_cmd *cmd);
+void scst_update_lat_stats(struct scst_cmd *cmd);
+
+#else
+
+static inline void scst_set_start_time(struct scst_cmd *cmd) {}
+static inline void scst_set_cur_start(struct scst_cmd *cmd) {}
+static inline void scst_set_parse_time(struct scst_cmd *cmd) {}
+static inline void scst_set_alloc_buf_time(struct scst_cmd *cmd) {}
+static inline void scst_set_restart_waiting_time(struct scst_cmd *cmd) {}
+static inline void scst_set_rdy_to_xfer_time(struct scst_cmd *cmd) {}
+static inline void scst_set_pre_exec_time(struct scst_cmd *cmd) {}
+static inline void scst_set_exec_time(struct scst_cmd *cmd) {}
+static inline void scst_set_dev_done_time(struct scst_cmd *cmd) {}
+static inline void scst_set_xmit_time(struct scst_cmd *cmd) {}
+static inline void scst_set_tgt_on_free_time(struct scst_cmd *cmd) {}
+static inline void scst_set_dev_on_free_time(struct scst_cmd *cmd) {}
+static inline void scst_update_lat_stats(struct scst_cmd *cmd) {}
+
+#endif /* CONFIG_SCST_MEASURE_LATENCY */
+
+#endif /* __SCST_PRIV_H */