drivers/s390/scsi/zfcp_qdio.c - kernel/msm-4.9 - Gitiles

 /*
  * zfcp device driver
  *
  * Setup and helper functions to access QDIO.
  *
  * Copyright IBM Corporation 2002, 2008
  */

 #define KMSG_COMPONENT "zfcp"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

 #include "zfcp_ext.h"

 #define QBUFF_PER_PAGE		(PAGE_SIZE / sizeof(struct qdio_buffer))

 static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)
 {
 	int pos;

 	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
 		sbal[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
 		if (!sbal[pos])
 			return -ENOMEM;
 	}
 	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
 		if (pos % QBUFF_PER_PAGE)
 			sbal[pos] = sbal[pos - 1] + 1;
 	return 0;
 }

 static struct qdio_buffer_element *
 zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
 {
 	return &q->sbal[sbal_idx]->element[sbale_idx];
 }

 /**
  * zfcp_qdio_free - free memory used by request- and resposne queue
  * @adapter: pointer to the zfcp_adapter structure
  */
 void zfcp_qdio_free(struct zfcp_adapter *adapter)
 {
 	struct qdio_buffer **sbal_req, **sbal_resp;
 	int p;

 	if (adapter->ccw_device)
 		qdio_free(adapter->ccw_device);

 	sbal_req = adapter->req_q.sbal;
 	sbal_resp = adapter->resp_q.sbal;

 	for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
 		free_page((unsigned long) sbal_req[p]);
 		free_page((unsigned long) sbal_resp[p]);
 	}
 }

 static void zfcp_qdio_handler_error(struct zfcp_adapter *adapter, char *id)
 {
 	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");

 	zfcp_erp_adapter_reopen(adapter,
 				ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
 				ZFCP_STATUS_COMMON_ERP_FAILED, id, NULL);
 }

 static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
 {
 	int i, sbal_idx;

 	for (i = first; i < first + cnt; i++) {
 		sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
 		memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
 	}
 }

 /* this needs to be called prior to updating the queue fill level */
 static void zfcp_qdio_account(struct zfcp_adapter *adapter)
 {
 	ktime_t now;
 	s64 span;
 	int free, used;

 	spin_lock(&adapter->qdio_stat_lock);
 	now = ktime_get();
 	span = ktime_us_delta(now, adapter->req_q_time);
 	free = max(0, atomic_read(&adapter->req_q.count));
 	used = QDIO_MAX_BUFFERS_PER_Q - free;
 	adapter->req_q_util += used * span;
 	adapter->req_q_time = now;
 	spin_unlock(&adapter->qdio_stat_lock);
 }

 static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
 			      int queue_no, int first, int count,
 			      unsigned long parm)
 {
 	struct zfcp_adapter *adapter = (struct zfcp_adapter *) parm;
 	struct zfcp_qdio_queue *queue = &adapter->req_q;

 	if (unlikely(qdio_err)) {
 		zfcp_hba_dbf_event_qdio(adapter, qdio_err, first, count);
 		zfcp_qdio_handler_error(adapter, "qdireq1");
 		return;
 	}

 	/* cleanup all SBALs being program-owned now */
 	zfcp_qdio_zero_sbals(queue->sbal, first, count);

 	zfcp_qdio_account(adapter);
 	atomic_add(count, &queue->count);
 	wake_up(&adapter->request_wq);
 }

 static void zfcp_qdio_reqid_check(struct zfcp_adapter *adapter,
 				  unsigned long req_id, int sbal_idx)
 {
 	struct zfcp_fsf_req *fsf_req;
 	unsigned long flags;

 	spin_lock_irqsave(&adapter->req_list_lock, flags);
 	fsf_req = zfcp_reqlist_find(adapter, req_id);

 	if (!fsf_req)
 		/*
 		 * Unknown request means that we have potentially memory
 		 * corruption and must stop the machine immediatly.
 		 */
 		panic("error: unknown request id (%lx) on adapter %s.\n",
 		      req_id, dev_name(&adapter->ccw_device->dev));

 	zfcp_reqlist_remove(adapter, fsf_req);
 	spin_unlock_irqrestore(&adapter->req_list_lock, flags);

 	fsf_req->sbal_response = sbal_idx;
 	fsf_req->qdio_inb_usage = atomic_read(&adapter->resp_q.count);
 	zfcp_fsf_req_complete(fsf_req);
 }

 static void zfcp_qdio_resp_put_back(struct zfcp_adapter *adapter, int processed)
 {
 	struct zfcp_qdio_queue *queue = &adapter->resp_q;
 	struct ccw_device *cdev = adapter->ccw_device;
 	u8 count, start = queue->first;
 	unsigned int retval;

 	count = atomic_read(&queue->count) + processed;

 	retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);

 	if (unlikely(retval)) {
 		atomic_set(&queue->count, count);
 		/* FIXME: Recover this with an adapter reopen? */
 	} else {
 		queue->first += count;
 		queue->first %= QDIO_MAX_BUFFERS_PER_Q;
 		atomic_set(&queue->count, 0);
 	}
 }

 static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
 			       int queue_no, int first, int count,
 			       unsigned long parm)
 {
 	struct zfcp_adapter *adapter = (struct zfcp_adapter *) parm;
 	struct zfcp_qdio_queue *queue = &adapter->resp_q;
 	struct qdio_buffer_element *sbale;
 	int sbal_idx, sbale_idx, sbal_no;

 	if (unlikely(qdio_err)) {
 		zfcp_hba_dbf_event_qdio(adapter, qdio_err, first, count);
 		zfcp_qdio_handler_error(adapter, "qdires1");
 		return;
 	}

 	/*
 	 * go through all SBALs from input queue currently
 	 * returned by QDIO layer
 	 */
 	for (sbal_no = 0; sbal_no < count; sbal_no++) {
 		sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;

 		/* go through all SBALEs of SBAL */
 		for (sbale_idx = 0; sbale_idx < QDIO_MAX_ELEMENTS_PER_BUFFER;
 		     sbale_idx++) {
 			sbale = zfcp_qdio_sbale(queue, sbal_idx, sbale_idx);
 			zfcp_qdio_reqid_check(adapter,
 					      (unsigned long) sbale->addr,
 					      sbal_idx);
 			if (likely(sbale->flags & SBAL_FLAGS_LAST_ENTRY))
 				break;
 		};

 		if (unlikely(!(sbale->flags & SBAL_FLAGS_LAST_ENTRY)))
 			dev_warn(&adapter->ccw_device->dev,
 				 "A QDIO protocol error occurred, "
 				 "operations continue\n");
 	}

 	/*
 	 * put range of SBALs back to response queue
 	 * (including SBALs which have already been free before)
 	 */
 	zfcp_qdio_resp_put_back(adapter, count);
 }

 /**
  * zfcp_qdio_sbale_req - return ptr to SBALE of req_q for a struct zfcp_fsf_req
  * @fsf_req: pointer to struct fsf_req
  * Returns: pointer to qdio_buffer_element (SBALE) structure
  */
 struct qdio_buffer_element *zfcp_qdio_sbale_req(struct zfcp_fsf_req *req)
 {
 	return zfcp_qdio_sbale(&req->adapter->req_q, req->sbal_last, 0);
 }

 /**
  * zfcp_qdio_sbale_curr - return curr SBALE on req_q for a struct zfcp_fsf_req
  * @fsf_req: pointer to struct fsf_req
  * Returns: pointer to qdio_buffer_element (SBALE) structure
  */
 struct qdio_buffer_element *zfcp_qdio_sbale_curr(struct zfcp_fsf_req *req)
 {
 	return zfcp_qdio_sbale(&req->adapter->req_q, req->sbal_last,
 			       req->sbale_curr);
 }

 static void zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
 {
 	int count = atomic_read(&fsf_req->adapter->req_q.count);
 	count = min(count, max_sbals);
 	fsf_req->sbal_limit = (fsf_req->sbal_first + count - 1)
 					% QDIO_MAX_BUFFERS_PER_Q;
 }

 static struct qdio_buffer_element *
 zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
 {
 	struct qdio_buffer_element *sbale;

 	/* set last entry flag in current SBALE of current SBAL */
 	sbale = zfcp_qdio_sbale_curr(fsf_req);
 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;

 	/* don't exceed last allowed SBAL */
 	if (fsf_req->sbal_last == fsf_req->sbal_limit)
 		return NULL;

 	/* set chaining flag in first SBALE of current SBAL */
 	sbale = zfcp_qdio_sbale_req(fsf_req);
 	sbale->flags |= SBAL_FLAGS0_MORE_SBALS;

 	/* calculate index of next SBAL */
 	fsf_req->sbal_last++;
 	fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;

 	/* keep this requests number of SBALs up-to-date */
 	fsf_req->sbal_number++;

 	/* start at first SBALE of new SBAL */
 	fsf_req->sbale_curr = 0;

 	/* set storage-block type for new SBAL */
 	sbale = zfcp_qdio_sbale_curr(fsf_req);
 	sbale->flags |= sbtype;

 	return sbale;
 }

 static struct qdio_buffer_element *
 zfcp_qdio_sbale_next(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
 {
 	if (fsf_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
 		return zfcp_qdio_sbal_chain(fsf_req, sbtype);
 	fsf_req->sbale_curr++;
 	return zfcp_qdio_sbale_curr(fsf_req);
 }

 static void zfcp_qdio_undo_sbals(struct zfcp_fsf_req *fsf_req)
 {
 	struct qdio_buffer **sbal = fsf_req->adapter->req_q.sbal;
 	int first = fsf_req->sbal_first;
 	int last = fsf_req->sbal_last;
 	int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
 		QDIO_MAX_BUFFERS_PER_Q + 1;
 	zfcp_qdio_zero_sbals(sbal, first, count);
 }

 static int zfcp_qdio_fill_sbals(struct zfcp_fsf_req *fsf_req,
 				unsigned int sbtype, void *start_addr,
 				unsigned int total_length)
 {
 	struct qdio_buffer_element *sbale;
 	unsigned long remaining, length;
 	void *addr;

 	/* split segment up */
 	for (addr = start_addr, remaining = total_length; remaining > 0;
 	     addr += length, remaining -= length) {
 		sbale = zfcp_qdio_sbale_next(fsf_req, sbtype);
 		if (!sbale) {
 			atomic_inc(&fsf_req->adapter->qdio_outb_full);
 			zfcp_qdio_undo_sbals(fsf_req);
 			return -EINVAL;
 		}

 		/* new piece must not exceed next page boundary */
 		length = min(remaining,
 			     (PAGE_SIZE - ((unsigned long)addr &
 					   (PAGE_SIZE - 1))));
 		sbale->addr = addr;
 		sbale->length = length;
 	}
 	return 0;
 }

 /**
  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
  * @fsf_req: request to be processed
  * @sbtype: SBALE flags
  * @sg: scatter-gather list
  * @max_sbals: upper bound for number of SBALs to be used
  * Returns: number of bytes, or error (negativ)
  */
 int zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
 			    struct scatterlist *sg, int max_sbals)
 {
 	struct qdio_buffer_element *sbale;
 	int retval, bytes = 0;

 	/* figure out last allowed SBAL */
 	zfcp_qdio_sbal_limit(fsf_req, max_sbals);

 	/* set storage-block type for this request */
 	sbale = zfcp_qdio_sbale_req(fsf_req);
 	sbale->flags |= sbtype;

 	for (; sg; sg = sg_next(sg)) {
 		retval = zfcp_qdio_fill_sbals(fsf_req, sbtype, sg_virt(sg),
 					      sg->length);
 		if (retval < 0)
 			return retval;
 		bytes += sg->length;
 	}

 	/* assume that no other SBALEs are to follow in the same SBAL */
 	sbale = zfcp_qdio_sbale_curr(fsf_req);
 	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;

 	return bytes;
 }

 /**
  * zfcp_qdio_send - set PCI flag in first SBALE and send req to QDIO
  * @fsf_req: pointer to struct zfcp_fsf_req
  * Returns: 0 on success, error otherwise
  */
 int zfcp_qdio_send(struct zfcp_fsf_req *fsf_req)
 {
 	struct zfcp_adapter *adapter = fsf_req->adapter;
 	struct zfcp_qdio_queue *req_q = &adapter->req_q;
 	int first = fsf_req->sbal_first;
 	int count = fsf_req->sbal_number;
 	int retval;
 	unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;

 	zfcp_qdio_account(adapter);

 	retval = do_QDIO(adapter->ccw_device, qdio_flags, 0, first, count);
 	if (unlikely(retval)) {
 		zfcp_qdio_zero_sbals(req_q->sbal, first, count);
 		return retval;
 	}

 	/* account for transferred buffers */
 	atomic_sub(count, &req_q->count);
 	req_q->first += count;
 	req_q->first %= QDIO_MAX_BUFFERS_PER_Q;
 	return 0;
 }

 /**
  * zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
  * @adapter: pointer to struct zfcp_adapter
  * Returns: -ENOMEM on memory allocation error or return value from
  *          qdio_allocate
  */
 int zfcp_qdio_allocate(struct zfcp_adapter *adapter)
 {
 	struct qdio_initialize *init_data;

 	if (zfcp_qdio_buffers_enqueue(adapter->req_q.sbal) ||
 		   zfcp_qdio_buffers_enqueue(adapter->resp_q.sbal))
 		return -ENOMEM;

 	init_data = &adapter->qdio_init_data;

 	init_data->cdev = adapter->ccw_device;
 	init_data->q_format = QDIO_ZFCP_QFMT;
 	memcpy(init_data->adapter_name, dev_name(&adapter->ccw_device->dev), 8);
 	ASCEBC(init_data->adapter_name, 8);
 	init_data->qib_param_field_format = 0;
 	init_data->qib_param_field = NULL;
 	init_data->input_slib_elements = NULL;
 	init_data->output_slib_elements = NULL;
 	init_data->no_input_qs = 1;
 	init_data->no_output_qs = 1;
 	init_data->input_handler = zfcp_qdio_int_resp;
 	init_data->output_handler = zfcp_qdio_int_req;
 	init_data->int_parm = (unsigned long) adapter;
 	init_data->flags = QDIO_INBOUND_0COPY_SBALS |
 			QDIO_OUTBOUND_0COPY_SBALS | QDIO_USE_OUTBOUND_PCIS;
 	init_data->input_sbal_addr_array =
 			(void **) (adapter->resp_q.sbal);
 	init_data->output_sbal_addr_array =
 			(void **) (adapter->req_q.sbal);

 	return qdio_allocate(init_data);
 }

 /**
  * zfcp_close_qdio - close qdio queues for an adapter
  */
 void zfcp_qdio_close(struct zfcp_adapter *adapter)
 {
 	struct zfcp_qdio_queue *req_q;
 	int first, count;

 	if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
 		return;

 	/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
 	req_q = &adapter->req_q;
 	spin_lock_bh(&adapter->req_q_lock);
 	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
 	spin_unlock_bh(&adapter->req_q_lock);

 	qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);

 	/* cleanup used outbound sbals */
 	count = atomic_read(&req_q->count);
 	if (count < QDIO_MAX_BUFFERS_PER_Q) {
 		first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
 		count = QDIO_MAX_BUFFERS_PER_Q - count;
 		zfcp_qdio_zero_sbals(req_q->sbal, first, count);
 	}
 	req_q->first = 0;
 	atomic_set(&req_q->count, 0);
 	adapter->resp_q.first = 0;
 	atomic_set(&adapter->resp_q.count, 0);
 }

 /**
  * zfcp_qdio_open - prepare and initialize response queue
  * @adapter: pointer to struct zfcp_adapter
  * Returns: 0 on success, otherwise -EIO
  */
 int zfcp_qdio_open(struct zfcp_adapter *adapter)
 {
 	struct qdio_buffer_element *sbale;
 	int cc;

 	if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
 		return -EIO;

 	if (qdio_establish(&adapter->qdio_init_data))
 		goto failed_establish;

 	if (qdio_activate(adapter->ccw_device))
 		goto failed_qdio;

 	for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
 		sbale = &(adapter->resp_q.sbal[cc]->element[0]);
 		sbale->length = 0;
 		sbale->flags = SBAL_FLAGS_LAST_ENTRY;
 		sbale->addr = NULL;
 	}

 	if (do_QDIO(adapter->ccw_device, QDIO_FLAG_SYNC_INPUT, 0, 0,
 		     QDIO_MAX_BUFFERS_PER_Q))
 		goto failed_qdio;

 	/* set index of first avalable SBALS / number of available SBALS */
 	adapter->req_q.first = 0;
 	atomic_set(&adapter->req_q.count, QDIO_MAX_BUFFERS_PER_Q);

 	return 0;

 failed_qdio:
 	qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);
 failed_establish:
 	dev_err(&adapter->ccw_device->dev,
 		"Setting up the QDIO connection to the FCP adapter failed\n");
 	return -EIO;
 }
	/*
	* zfcp device driver
	*
	* Setup and helper functions to access QDIO.
	*
	* Copyright IBM Corporation 2002, 2008
	*/

	#define KMSG_COMPONENT "zfcp"
	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

	#include "zfcp_ext.h"

	#define QBUFF_PER_PAGE (PAGE_SIZE / sizeof(struct qdio_buffer))

	static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)
	{
	int pos;

	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
	sbal[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
	if (!sbal[pos])
	return -ENOMEM;
	}
	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
	if (pos % QBUFF_PER_PAGE)
	sbal[pos] = sbal[pos - 1] + 1;
	return 0;
	}

	static struct qdio_buffer_element *
	zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
	{
	return &q->sbal[sbal_idx]->element[sbale_idx];
	}

	/**
	* zfcp_qdio_free - free memory used by request- and resposne queue
	* @adapter: pointer to the zfcp_adapter structure
	*/
	void zfcp_qdio_free(struct zfcp_adapter *adapter)
	{
	struct qdio_buffer sbal_req, sbal_resp;
	int p;

	if (adapter->ccw_device)
	qdio_free(adapter->ccw_device);

	sbal_req = adapter->req_q.sbal;
	sbal_resp = adapter->resp_q.sbal;

	for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
	free_page((unsigned long) sbal_req[p]);
	free_page((unsigned long) sbal_resp[p]);
	}
	}

	static void zfcp_qdio_handler_error(struct zfcp_adapter adapter, char id)
	{
	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");

	zfcp_erp_adapter_reopen(adapter,
	ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED \|
	ZFCP_STATUS_COMMON_ERP_FAILED, id, NULL);
	}

	static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
	{
	int i, sbal_idx;

	for (i = first; i < first + cnt; i++) {
	sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
	memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
	}
	}

	/* this needs to be called prior to updating the queue fill level */
	static void zfcp_qdio_account(struct zfcp_adapter *adapter)
	{
	ktime_t now;
	s64 span;
	int free, used;

	spin_lock(&adapter->qdio_stat_lock);
	now = ktime_get();
	span = ktime_us_delta(now, adapter->req_q_time);
	free = max(0, atomic_read(&adapter->req_q.count));
	used = QDIO_MAX_BUFFERS_PER_Q - free;
	adapter->req_q_util += used * span;
	adapter->req_q_time = now;
	spin_unlock(&adapter->qdio_stat_lock);
	}

	static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
	int queue_no, int first, int count,
	unsigned long parm)
	{
	struct zfcp_adapter adapter = (struct zfcp_adapter ) parm;
	struct zfcp_qdio_queue *queue = &adapter->req_q;

	if (unlikely(qdio_err)) {
	zfcp_hba_dbf_event_qdio(adapter, qdio_err, first, count);
	zfcp_qdio_handler_error(adapter, "qdireq1");
	return;
	}

	/* cleanup all SBALs being program-owned now */
	zfcp_qdio_zero_sbals(queue->sbal, first, count);

	zfcp_qdio_account(adapter);
	atomic_add(count, &queue->count);
	wake_up(&adapter->request_wq);
	}

	static void zfcp_qdio_reqid_check(struct zfcp_adapter *adapter,
	unsigned long req_id, int sbal_idx)
	{
	struct zfcp_fsf_req *fsf_req;
	unsigned long flags;

	spin_lock_irqsave(&adapter->req_list_lock, flags);
	fsf_req = zfcp_reqlist_find(adapter, req_id);

	if (!fsf_req)
	/*
	* Unknown request means that we have potentially memory
	* corruption and must stop the machine immediatly.
	*/
	panic("error: unknown request id (%lx) on adapter %s.\n",
	req_id, dev_name(&adapter->ccw_device->dev));

	zfcp_reqlist_remove(adapter, fsf_req);
	spin_unlock_irqrestore(&adapter->req_list_lock, flags);

	fsf_req->sbal_response = sbal_idx;
	fsf_req->qdio_inb_usage = atomic_read(&adapter->resp_q.count);
	zfcp_fsf_req_complete(fsf_req);
	}

	static void zfcp_qdio_resp_put_back(struct zfcp_adapter *adapter, int processed)
	{
	struct zfcp_qdio_queue *queue = &adapter->resp_q;
	struct ccw_device *cdev = adapter->ccw_device;
	u8 count, start = queue->first;
	unsigned int retval;

	count = atomic_read(&queue->count) + processed;

	retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);

	if (unlikely(retval)) {
	atomic_set(&queue->count, count);
	/* FIXME: Recover this with an adapter reopen? */
	} else {
	queue->first += count;
	queue->first %= QDIO_MAX_BUFFERS_PER_Q;
	atomic_set(&queue->count, 0);
	}
	}

	static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
	int queue_no, int first, int count,
	unsigned long parm)
	{
	struct zfcp_adapter adapter = (struct zfcp_adapter ) parm;
	struct zfcp_qdio_queue *queue = &adapter->resp_q;
	struct qdio_buffer_element *sbale;
	int sbal_idx, sbale_idx, sbal_no;

	if (unlikely(qdio_err)) {
	zfcp_hba_dbf_event_qdio(adapter, qdio_err, first, count);
	zfcp_qdio_handler_error(adapter, "qdires1");
	return;
	}

	/*
	* go through all SBALs from input queue currently
	* returned by QDIO layer
	*/
	for (sbal_no = 0; sbal_no < count; sbal_no++) {
	sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;

	/* go through all SBALEs of SBAL */
	for (sbale_idx = 0; sbale_idx < QDIO_MAX_ELEMENTS_PER_BUFFER;
	sbale_idx++) {
	sbale = zfcp_qdio_sbale(queue, sbal_idx, sbale_idx);
	zfcp_qdio_reqid_check(adapter,
	(unsigned long) sbale->addr,
	sbal_idx);
	if (likely(sbale->flags & SBAL_FLAGS_LAST_ENTRY))
	break;
	};

	if (unlikely(!(sbale->flags & SBAL_FLAGS_LAST_ENTRY)))
	dev_warn(&adapter->ccw_device->dev,
	"A QDIO protocol error occurred, "
	"operations continue\n");
	}

	/*
	* put range of SBALs back to response queue
	* (including SBALs which have already been free before)
	*/
	zfcp_qdio_resp_put_back(adapter, count);
	}

	/**
	* zfcp_qdio_sbale_req - return ptr to SBALE of req_q for a struct zfcp_fsf_req
	* @fsf_req: pointer to struct fsf_req
	* Returns: pointer to qdio_buffer_element (SBALE) structure
	*/
	struct qdio_buffer_element zfcp_qdio_sbale_req(struct zfcp_fsf_req req)
	{
	return zfcp_qdio_sbale(&req->adapter->req_q, req->sbal_last, 0);
	}

	/**
	* zfcp_qdio_sbale_curr - return curr SBALE on req_q for a struct zfcp_fsf_req
	* @fsf_req: pointer to struct fsf_req
	* Returns: pointer to qdio_buffer_element (SBALE) structure
	*/
	struct qdio_buffer_element zfcp_qdio_sbale_curr(struct zfcp_fsf_req req)
	{
	return zfcp_qdio_sbale(&req->adapter->req_q, req->sbal_last,
	req->sbale_curr);
	}

	static void zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
	{
	int count = atomic_read(&fsf_req->adapter->req_q.count);
	count = min(count, max_sbals);
	fsf_req->sbal_limit = (fsf_req->sbal_first + count - 1)
	% QDIO_MAX_BUFFERS_PER_Q;
	}

	static struct qdio_buffer_element *
	zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
	{
	struct qdio_buffer_element *sbale;

	/* set last entry flag in current SBALE of current SBAL */
	sbale = zfcp_qdio_sbale_curr(fsf_req);
	sbale->flags \|= SBAL_FLAGS_LAST_ENTRY;

	/* don't exceed last allowed SBAL */
	if (fsf_req->sbal_last == fsf_req->sbal_limit)
	return NULL;

	/* set chaining flag in first SBALE of current SBAL */
	sbale = zfcp_qdio_sbale_req(fsf_req);
	sbale->flags \|= SBAL_FLAGS0_MORE_SBALS;

	/* calculate index of next SBAL */
	fsf_req->sbal_last++;
	fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;

	/* keep this requests number of SBALs up-to-date */
	fsf_req->sbal_number++;

	/* start at first SBALE of new SBAL */
	fsf_req->sbale_curr = 0;

	/* set storage-block type for new SBAL */
	sbale = zfcp_qdio_sbale_curr(fsf_req);
	sbale->flags \|= sbtype;

	return sbale;
	}

	static struct qdio_buffer_element *
	zfcp_qdio_sbale_next(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
	{
	if (fsf_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)
	return zfcp_qdio_sbal_chain(fsf_req, sbtype);
	fsf_req->sbale_curr++;
	return zfcp_qdio_sbale_curr(fsf_req);
	}

	static void zfcp_qdio_undo_sbals(struct zfcp_fsf_req *fsf_req)
	{
	struct qdio_buffer **sbal = fsf_req->adapter->req_q.sbal;
	int first = fsf_req->sbal_first;
	int last = fsf_req->sbal_last;
	int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
	QDIO_MAX_BUFFERS_PER_Q + 1;
	zfcp_qdio_zero_sbals(sbal, first, count);
	}

	static int zfcp_qdio_fill_sbals(struct zfcp_fsf_req *fsf_req,
	unsigned int sbtype, void *start_addr,
	unsigned int total_length)
	{
	struct qdio_buffer_element *sbale;
	unsigned long remaining, length;
	void *addr;

	/* split segment up */
	for (addr = start_addr, remaining = total_length; remaining > 0;
	addr += length, remaining -= length) {
	sbale = zfcp_qdio_sbale_next(fsf_req, sbtype);
	if (!sbale) {
	atomic_inc(&fsf_req->adapter->qdio_outb_full);
	zfcp_qdio_undo_sbals(fsf_req);
	return -EINVAL;
	}

	/* new piece must not exceed next page boundary */
	length = min(remaining,
	(PAGE_SIZE - ((unsigned long)addr &
	(PAGE_SIZE - 1))));
	sbale->addr = addr;
	sbale->length = length;
	}
	return 0;
	}

	/**
	* zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
	* @fsf_req: request to be processed
	* @sbtype: SBALE flags
	* @sg: scatter-gather list
	* @max_sbals: upper bound for number of SBALs to be used
	* Returns: number of bytes, or error (negativ)
	*/
	int zfcp_qdio_sbals_from_sg(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
	struct scatterlist *sg, int max_sbals)
	{
	struct qdio_buffer_element *sbale;
	int retval, bytes = 0;

	/* figure out last allowed SBAL */
	zfcp_qdio_sbal_limit(fsf_req, max_sbals);

	/* set storage-block type for this request */
	sbale = zfcp_qdio_sbale_req(fsf_req);
	sbale->flags \|= sbtype;

	for (; sg; sg = sg_next(sg)) {
	retval = zfcp_qdio_fill_sbals(fsf_req, sbtype, sg_virt(sg),
	sg->length);
	if (retval < 0)
	return retval;
	bytes += sg->length;
	}

	/* assume that no other SBALEs are to follow in the same SBAL */
	sbale = zfcp_qdio_sbale_curr(fsf_req);
	sbale->flags \|= SBAL_FLAGS_LAST_ENTRY;

	return bytes;
	}

	/**
	* zfcp_qdio_send - set PCI flag in first SBALE and send req to QDIO
	* @fsf_req: pointer to struct zfcp_fsf_req
	* Returns: 0 on success, error otherwise
	*/
	int zfcp_qdio_send(struct zfcp_fsf_req *fsf_req)
	{
	struct zfcp_adapter *adapter = fsf_req->adapter;
	struct zfcp_qdio_queue *req_q = &adapter->req_q;
	int first = fsf_req->sbal_first;
	int count = fsf_req->sbal_number;
	int retval;
	unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;

	zfcp_qdio_account(adapter);

	retval = do_QDIO(adapter->ccw_device, qdio_flags, 0, first, count);
	if (unlikely(retval)) {
	zfcp_qdio_zero_sbals(req_q->sbal, first, count);
	return retval;
	}

	/* account for transferred buffers */
	atomic_sub(count, &req_q->count);
	req_q->first += count;
	req_q->first %= QDIO_MAX_BUFFERS_PER_Q;
	return 0;
	}

	/**
	* zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
	* @adapter: pointer to struct zfcp_adapter
	* Returns: -ENOMEM on memory allocation error or return value from
	* qdio_allocate
	*/
	int zfcp_qdio_allocate(struct zfcp_adapter *adapter)
	{
	struct qdio_initialize *init_data;

	if (zfcp_qdio_buffers_enqueue(adapter->req_q.sbal) \|\|
	zfcp_qdio_buffers_enqueue(adapter->resp_q.sbal))
	return -ENOMEM;

	init_data = &adapter->qdio_init_data;

	init_data->cdev = adapter->ccw_device;
	init_data->q_format = QDIO_ZFCP_QFMT;
	memcpy(init_data->adapter_name, dev_name(&adapter->ccw_device->dev), 8);
	ASCEBC(init_data->adapter_name, 8);
	init_data->qib_param_field_format = 0;
	init_data->qib_param_field = NULL;
	init_data->input_slib_elements = NULL;
	init_data->output_slib_elements = NULL;
	init_data->no_input_qs = 1;
	init_data->no_output_qs = 1;
	init_data->input_handler = zfcp_qdio_int_resp;
	init_data->output_handler = zfcp_qdio_int_req;
	init_data->int_parm = (unsigned long) adapter;
	init_data->flags = QDIO_INBOUND_0COPY_SBALS \|
	QDIO_OUTBOUND_0COPY_SBALS \| QDIO_USE_OUTBOUND_PCIS;
	init_data->input_sbal_addr_array =
	(void **) (adapter->resp_q.sbal);
	init_data->output_sbal_addr_array =
	(void **) (adapter->req_q.sbal);

	return qdio_allocate(init_data);
	}

	/**
	* zfcp_close_qdio - close qdio queues for an adapter
	*/
	void zfcp_qdio_close(struct zfcp_adapter *adapter)
	{
	struct zfcp_qdio_queue *req_q;
	int first, count;

	if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
	return;

	/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
	req_q = &adapter->req_q;
	spin_lock_bh(&adapter->req_q_lock);
	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
	spin_unlock_bh(&adapter->req_q_lock);

	qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);

	/* cleanup used outbound sbals */
	count = atomic_read(&req_q->count);
	if (count < QDIO_MAX_BUFFERS_PER_Q) {
	first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
	count = QDIO_MAX_BUFFERS_PER_Q - count;
	zfcp_qdio_zero_sbals(req_q->sbal, first, count);
	}
	req_q->first = 0;
	atomic_set(&req_q->count, 0);
	adapter->resp_q.first = 0;
	atomic_set(&adapter->resp_q.count, 0);
	}

	/**
	* zfcp_qdio_open - prepare and initialize response queue
	* @adapter: pointer to struct zfcp_adapter
	* Returns: 0 on success, otherwise -EIO
	*/
	int zfcp_qdio_open(struct zfcp_adapter *adapter)
	{
	struct qdio_buffer_element *sbale;
	int cc;

	if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
	return -EIO;

	if (qdio_establish(&adapter->qdio_init_data))
	goto failed_establish;

	if (qdio_activate(adapter->ccw_device))
	goto failed_qdio;

	for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
	sbale = &(adapter->resp_q.sbal[cc]->element[0]);
	sbale->length = 0;
	sbale->flags = SBAL_FLAGS_LAST_ENTRY;
	sbale->addr = NULL;
	}

	if (do_QDIO(adapter->ccw_device, QDIO_FLAG_SYNC_INPUT, 0, 0,
	QDIO_MAX_BUFFERS_PER_Q))
	goto failed_qdio;

	/* set index of first avalable SBALS / number of available SBALS */
	adapter->req_q.first = 0;
	atomic_set(&adapter->req_q.count, QDIO_MAX_BUFFERS_PER_Q);

	return 0;

	failed_qdio:
	qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);
	failed_establish:
	dev_err(&adapter->ccw_device->dev,
	"Setting up the QDIO connection to the FCP adapter failed\n");
	return -EIO;
	}