/*-
 *   BSD LICENSE
 *
 *   Copyright (C) 2008-2012 Daisuke Aoyama <aoyama@peach.ne.jp>.
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "scsi_internal.h"
#include "spdk/endian.h"
#include "spdk/env.h"
#include "spdk/thread.h"
#include "spdk/event.h"
#include "spdk/util.h"

void
spdk_scsi_lun_complete_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
{
	if (lun) {
		TAILQ_REMOVE(&lun->tasks, task, scsi_link);
		spdk_trace_record(TRACE_SCSI_TASK_DONE, lun->dev->id, 0, (uintptr_t)task, 0);
	}
	task->cpl_fn(task);
}

void
spdk_scsi_lun_complete_mgmt_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
{
	if (task->function == SPDK_SCSI_TASK_FUNC_LUN_RESET &&
	    task->status == SPDK_SCSI_STATUS_GOOD) {
		/*
		 * The backend LUN device was just reset. If there are active tasks
		 * in the backend, it means that LUN reset fails, and we set failure
		 * status to LUN reset task.
		 */
		if (spdk_scsi_lun_has_pending_tasks(lun)) {
			SPDK_ERRLOG("lun->tasks should be empty after reset\n");
			task->response = SPDK_SCSI_TASK_MGMT_RESP_TARGET_FAILURE;
		}
	}
	task->cpl_fn(task);
}

int
spdk_scsi_lun_task_mgmt_execute(struct spdk_scsi_task *task,
				enum spdk_scsi_task_func func)
{
	if (!task) {
		return -1;
	}

	if (!task->lun) {
		/* LUN does not exist */
		task->response = SPDK_SCSI_TASK_MGMT_RESP_INVALID_LUN;
		task->cpl_fn(task);
		return -1;
	}

	switch (func) {
	case SPDK_SCSI_TASK_FUNC_ABORT_TASK:
		task->response = SPDK_SCSI_TASK_MGMT_RESP_REJECT_FUNC_NOT_SUPPORTED;
		SPDK_ERRLOG("ABORT_TASK failed\n");
		break;

	case SPDK_SCSI_TASK_FUNC_ABORT_TASK_SET:
		task->response = SPDK_SCSI_TASK_MGMT_RESP_REJECT_FUNC_NOT_SUPPORTED;
		SPDK_ERRLOG("ABORT_TASK_SET failed\n");
		break;

	case SPDK_SCSI_TASK_FUNC_LUN_RESET:
		spdk_bdev_scsi_reset(task);
		return 0;

	default:
		SPDK_ERRLOG("Unknown Task Management Function!\n");
		/*
		 * Task management functions other than those above should never
		 * reach this point having been filtered by the frontend. Reject
		 * the task as being unsupported.
		 */
		task->response = SPDK_SCSI_TASK_MGMT_RESP_REJECT_FUNC_NOT_SUPPORTED;
		break;
	}

	spdk_scsi_lun_complete_mgmt_task(task->lun, task);

	return -1;
}

void
spdk_scsi_task_process_null_lun(struct spdk_scsi_task *task)
{
	uint8_t buffer[36];
	uint32_t allocation_len;
	uint32_t data_len;

	task->length = task->transfer_len;
	if (task->cdb[0] == SPDK_SPC_INQUIRY) {
		/*
		 * SPC-4 states that INQUIRY commands to an unsupported LUN
		 *  must be served with PERIPHERAL QUALIFIER = 0x3 and
		 *  PERIPHERAL DEVICE TYPE = 0x1F.
		 */
		data_len = sizeof(buffer);

		memset(buffer, 0, data_len);
		/* PERIPHERAL QUALIFIER(7-5) PERIPHERAL DEVICE TYPE(4-0) */
		buffer[0] = 0x03 << 5 | 0x1f;
		/* ADDITIONAL LENGTH */
		buffer[4] = data_len - 5;

		allocation_len = from_be16(&task->cdb[3]);
		if (spdk_scsi_task_scatter_data(task, buffer, spdk_min(allocation_len, data_len)) >= 0) {
			task->data_transferred = data_len;
			task->status = SPDK_SCSI_STATUS_GOOD;
		}
	} else {
		/* LOGICAL UNIT NOT SUPPORTED */
		spdk_scsi_task_set_status(task, SPDK_SCSI_STATUS_CHECK_CONDITION,
					  SPDK_SCSI_SENSE_ILLEGAL_REQUEST,
					  SPDK_SCSI_ASC_LOGICAL_UNIT_NOT_SUPPORTED,
					  SPDK_SCSI_ASCQ_CAUSE_NOT_REPORTABLE);
		task->data_transferred = 0;
	}
}

void
spdk_scsi_lun_execute_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
{
	int rc;

	task->status = SPDK_SCSI_STATUS_GOOD;
	spdk_trace_record(TRACE_SCSI_TASK_START, lun->dev->id, task->length, (uintptr_t)task, 0);
	TAILQ_INSERT_TAIL(&lun->tasks, task, scsi_link);
	if (!lun->removed) {
		rc = spdk_bdev_scsi_execute(task);
	} else {
		spdk_scsi_task_set_status(task, SPDK_SCSI_STATUS_CHECK_CONDITION,
					  SPDK_SCSI_SENSE_ABORTED_COMMAND,
					  SPDK_SCSI_ASC_NO_ADDITIONAL_SENSE,
					  SPDK_SCSI_ASCQ_CAUSE_NOT_REPORTABLE);
		rc = SPDK_SCSI_TASK_COMPLETE;
	}

	switch (rc) {
	case SPDK_SCSI_TASK_PENDING:
		break;

	case SPDK_SCSI_TASK_COMPLETE:
		spdk_scsi_lun_complete_task(lun, task);
		break;

	default:
		abort();
	}
}

static void
spdk_scsi_lun_remove(struct spdk_scsi_lun *lun)
{
	spdk_bdev_close(lun->bdev_desc);

	spdk_scsi_dev_delete_lun(lun->dev, lun);
	free(lun);
}

static int
spdk_scsi_lun_check_io_channel(void *arg)
{
	struct spdk_scsi_lun *lun = (struct spdk_scsi_lun *)arg;

	if (lun->io_channel) {
		return -1;
	}
	spdk_poller_unregister(&lun->hotremove_poller);

	spdk_scsi_lun_remove(lun);
	return -1;
}

static void
spdk_scsi_lun_notify_hot_remove(struct spdk_scsi_lun *lun)
{
	struct spdk_scsi_desc *desc, *tmp;

	if (lun->hotremove_cb) {
		lun->hotremove_cb(lun, lun->hotremove_ctx);
	}

	TAILQ_FOREACH_SAFE(desc, &lun->open_descs, link, tmp) {
		if (desc->hotremove_cb) {
			desc->hotremove_cb(lun, desc->hotremove_ctx);
		} else {
			spdk_scsi_lun_close(desc);
		}
	}

	if (lun->io_channel) {
		lun->hotremove_poller = spdk_poller_register(spdk_scsi_lun_check_io_channel,
					lun, 10);
	} else {
		spdk_scsi_lun_remove(lun);
	}
}

static int
spdk_scsi_lun_check_pending_tasks(void *arg)
{
	struct spdk_scsi_lun *lun = (struct spdk_scsi_lun *)arg;

	if (spdk_scsi_lun_has_pending_tasks(lun)) {
		return -1;
	}
	spdk_poller_unregister(&lun->hotremove_poller);

	spdk_scsi_lun_notify_hot_remove(lun);
	return -1;
}

static void
_spdk_scsi_lun_hot_remove(void *arg1)
{
	struct spdk_scsi_lun *lun = arg1;

	if (spdk_scsi_lun_has_pending_tasks(lun)) {
		lun->hotremove_poller = spdk_poller_register(spdk_scsi_lun_check_pending_tasks,
					lun, 10);
	} else {
		spdk_scsi_lun_notify_hot_remove(lun);
	}
}

static void
spdk_scsi_lun_hot_remove(void *remove_ctx)
{
	struct spdk_scsi_lun *lun = (struct spdk_scsi_lun *)remove_ctx;
	struct spdk_thread *thread;

	if (lun->removed) {
		return;
	}

	lun->removed = true;
	if (lun->io_channel == NULL) {
		_spdk_scsi_lun_hot_remove(lun);
		return;
	}

	thread = spdk_io_channel_get_thread(lun->io_channel);
	if (thread != spdk_get_thread()) {
		spdk_thread_send_msg(thread, _spdk_scsi_lun_hot_remove, lun);
	} else {
		_spdk_scsi_lun_hot_remove(lun);
	}
}

/**
 * \brief Constructs a new spdk_scsi_lun object based on the provided parameters.
 *
 * \param bdev  bdev associated with this LUN
 *
 * \return NULL if bdev == NULL
 * \return pointer to the new spdk_scsi_lun object otherwise
 */
_spdk_scsi_lun *
spdk_scsi_lun_construct(struct spdk_bdev *bdev,
			void (*hotremove_cb)(const struct spdk_scsi_lun *, void *),
			void *hotremove_ctx)
{
	struct spdk_scsi_lun *lun;
	int rc;

	if (bdev == NULL) {
		SPDK_ERRLOG("bdev must be non-NULL\n");
		return NULL;
	}

	lun = calloc(1, sizeof(*lun));
	if (lun == NULL) {
		SPDK_ERRLOG("could not allocate lun\n");
		return NULL;
	}

	rc = spdk_bdev_open(bdev, true, spdk_scsi_lun_hot_remove, lun, &lun->bdev_desc);

	if (rc != 0) {
		SPDK_ERRLOG("bdev %s cannot be opened, error=%d\n", spdk_bdev_get_name(bdev), rc);
		free(lun);
		return NULL;
	}

	TAILQ_INIT(&lun->tasks);

	lun->bdev = bdev;
	lun->io_channel = NULL;
	lun->hotremove_cb = hotremove_cb;
	lun->hotremove_ctx = hotremove_ctx;
	TAILQ_INIT(&lun->open_descs);

	return lun;
}

void
spdk_scsi_lun_destruct(struct spdk_scsi_lun *lun)
{
	spdk_scsi_lun_hot_remove(lun);
}

int
spdk_scsi_lun_open(struct spdk_scsi_lun *lun, spdk_scsi_remove_cb_t hotremove_cb,
		   void *hotremove_ctx, struct spdk_scsi_desc **_desc)
{
	struct spdk_scsi_desc *desc;

	desc = calloc(1, sizeof(*desc));
	if (desc == NULL) {
		SPDK_ERRLOG("calloc() failed for LUN descriptor.\n");
		return -ENOMEM;
	}

	TAILQ_INSERT_TAIL(&lun->open_descs, desc, link);

	desc->lun = lun;
	desc->hotremove_cb = hotremove_cb;
	desc->hotremove_ctx = hotremove_ctx;
	*_desc = desc;

	return 0;
}

void
spdk_scsi_lun_close(struct spdk_scsi_desc *desc)
{
	struct spdk_scsi_lun *lun = desc->lun;

	TAILQ_REMOVE(&lun->open_descs, desc, link);
	free(desc);

	assert(!TAILQ_EMPTY(&lun->open_descs) || lun->io_channel == NULL);
}

int
_spdk_scsi_lun_allocate_io_channel(struct spdk_scsi_lun *lun)
{
	if (lun->io_channel != NULL) {
		if (spdk_get_thread() == spdk_io_channel_get_thread(lun->io_channel)) {
			lun->ref++;
			return 0;
		}
		SPDK_ERRLOG("io_channel already allocated for lun %s\n",
			    spdk_bdev_get_name(lun->bdev));
		return -1;
	}

	lun->io_channel = spdk_bdev_get_io_channel(lun->bdev_desc);
	if (lun->io_channel == NULL) {
		return -1;
	}
	lun->ref = 1;
	return 0;
}

void
_spdk_scsi_lun_free_io_channel(struct spdk_scsi_lun *lun)
{
	if (lun->io_channel == NULL) {
		return;
	}

	if (spdk_get_thread() != spdk_io_channel_get_thread(lun->io_channel)) {
		SPDK_ERRLOG("io_channel was freed by different thread\n");
		return;
	}

	lun->ref--;
	if (lun->ref == 0) {
		spdk_put_io_channel(lun->io_channel);
		lun->io_channel = NULL;
	}
}

int
spdk_scsi_lun_allocate_io_channel(struct spdk_scsi_desc *desc)
{
	struct spdk_scsi_lun *lun = desc->lun;

	return _spdk_scsi_lun_allocate_io_channel(lun);
}

void
spdk_scsi_lun_free_io_channel(struct spdk_scsi_desc *desc)
{
	struct spdk_scsi_lun *lun = desc->lun;

	_spdk_scsi_lun_free_io_channel(lun);
}

int
spdk_scsi_lun_get_id(const struct spdk_scsi_lun *lun)
{
	return lun->id;
}

const char *
spdk_scsi_lun_get_bdev_name(const struct spdk_scsi_lun *lun)
{
	return spdk_bdev_get_name(lun->bdev);
}

const struct spdk_scsi_dev *
spdk_scsi_lun_get_dev(const struct spdk_scsi_lun *lun)
{
	return lun->dev;
}

bool
spdk_scsi_lun_has_pending_tasks(const struct spdk_scsi_lun *lun)
{
	return !TAILQ_EMPTY(&lun->tasks);
}

bool
spdk_scsi_lun_is_removing(const struct spdk_scsi_lun *lun)
{
	return lun->removed;
}