zfcp_qdio.c

linux-2.6.15.6

		atomic_set(&queue->free_count, count);
		ZFCP_LOG_DEBUG("clearing of inbound data regions failed, "
			       "queues may be down "
			       "(count=%d, start=%d, retval=%d)\n",
			       count, start, retval);
	} else {
		queue->free_index += count;
		queue->free_index %= QDIO_MAX_BUFFERS_PER_Q;
		atomic_set(&queue->free_count, 0);
		ZFCP_LOG_TRACE("%i buffers enqueued to response "
			       "queue at position %i\n", count, start);
	}
 out:
	return;
}

/*
 * function:	zfcp_qdio_reqid_check
 *
 * purpose:	checks for valid reqids or unsolicited status
 *
 * returns:	0 - valid request id or unsolicited status
 *		!0 - otherwise
 */
int
zfcp_qdio_reqid_check(struct zfcp_adapter *adapter, void *sbale_addr)
{
	struct zfcp_fsf_req *fsf_req;

	/* invalid (per convention used in this driver) */
	if (unlikely(!sbale_addr)) {
		ZFCP_LOG_NORMAL("bug: invalid reqid\n");
		return -EINVAL;
	}

	/* valid request id and thus (hopefully :) valid fsf_req address */
	fsf_req = (struct zfcp_fsf_req *) sbale_addr;

	/* serialize with zfcp_fsf_req_dismiss_all */
	spin_lock(&adapter->fsf_req_list_lock);
	if (list_empty(&adapter->fsf_req_list_head)) {
		spin_unlock(&adapter->fsf_req_list_lock);
		return 0;
	}
	list_del(&fsf_req->list);
	atomic_dec(&adapter->fsf_reqs_active);
	spin_unlock(&adapter->fsf_req_list_lock);
	
	if (unlikely(adapter != fsf_req->adapter)) {
		ZFCP_LOG_NORMAL("bug: invalid reqid (fsf_req=%p, "
				"fsf_req->adapter=%p, adapter=%p)\n",
				fsf_req, fsf_req->adapter, adapter);
		return -EINVAL;
	}

	/* finish the FSF request */
	zfcp_fsf_req_complete(fsf_req);

	return 0;
}

/**
 * zfcp_qdio_sbale_get - return pointer to SBALE of qdio_queue
 * @queue: queue from which SBALE should be returned
 * @sbal: specifies number of SBAL in queue
 * @sbale: specifes number of SBALE in SBAL
 */
static inline volatile struct qdio_buffer_element *
zfcp_qdio_sbale_get(struct zfcp_qdio_queue *queue, int sbal, int sbale)
{
	return &queue->buffer[sbal]->element[sbale];
}

/**
 * zfcp_qdio_sbale_req - return pointer to SBALE of request_queue for
 *	a struct zfcp_fsf_req
 */
inline volatile struct qdio_buffer_element *
zfcp_qdio_sbale_req(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
{
	return zfcp_qdio_sbale_get(&fsf_req->adapter->request_queue,
				   sbal, sbale);
}

/**
 * zfcp_qdio_sbale_resp - return pointer to SBALE of response_queue for
 *	a struct zfcp_fsf_req
 */
static inline volatile struct qdio_buffer_element *
zfcp_qdio_sbale_resp(struct zfcp_fsf_req *fsf_req, int sbal, int sbale)
{
	return zfcp_qdio_sbale_get(&fsf_req->adapter->response_queue,
				   sbal, sbale);
}

/**
 * zfcp_qdio_sbale_curr - return current SBALE on request_queue for
 *	a struct zfcp_fsf_req
 */
inline volatile struct qdio_buffer_element *
zfcp_qdio_sbale_curr(struct zfcp_fsf_req *fsf_req)
{
	return zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr,
				   fsf_req->sbale_curr);
}

/**
 * zfcp_qdio_sbal_limit - determine maximum number of SBALs that can be used
 *	on the request_queue for a struct zfcp_fsf_req
 * @fsf_req: the number of the last SBAL that can be used is stored herein
 * @max_sbals: used to pass an upper limit for the number of SBALs
 *
 * Note: We can assume at least one free SBAL in the request_queue when called.
 */
static inline void
zfcp_qdio_sbal_limit(struct zfcp_fsf_req *fsf_req, int max_sbals)
{
	int count = atomic_read(&fsf_req->adapter->request_queue.free_count);
	count = min(count, max_sbals);
	fsf_req->sbal_last  = fsf_req->sbal_first;
	fsf_req->sbal_last += (count - 1);
	fsf_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;
}

/**
 * zfcp_qdio_sbal_chain - chain SBALs if more than one SBAL is needed for a
 *	request
 * @fsf_req: zfcp_fsf_req to be processed
 * @sbtype: SBAL flags which have to be set in first SBALE of new SBAL
 *
 * This function changes sbal_curr, sbale_curr, sbal_number of fsf_req.
 */
static inline volatile struct qdio_buffer_element *
zfcp_qdio_sbal_chain(struct zfcp_fsf_req *fsf_req, unsigned long sbtype)
{
	volatile 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_curr == fsf_req->sbal_last)
		return NULL;

	/* set chaining flag in first SBALE of current SBAL */
	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
	sbale->flags |= SBAL_FLAGS0_MORE_SBALS;

	/* calculate index of next SBAL */
	fsf_req->sbal_curr++;
	fsf_req->sbal_curr %= 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;
}

/**
 * zfcp_qdio_sbale_next - switch to next SBALE, chain SBALs if needed
 */
static inline volatile 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);
}

/**
 * zfcp_qdio_sbals_zero - initialize SBALs between first and last in queue
 *	with zero from
 */
static inline int
zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *queue, int first, int last)
{
	struct qdio_buffer **buf = queue->buffer;
	int curr = first;
	int count = 0;

	for(;;) {
		curr %= QDIO_MAX_BUFFERS_PER_Q;
		count++;
		memset(buf[curr], 0, sizeof(struct qdio_buffer));
		if (curr == last)
			break;
		curr++;
	}
	return count;
}


/**
 * zfcp_qdio_sbals_wipe - reset all changes in SBALs for an fsf_req
 */
static inline int
zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *fsf_req)
{
	return zfcp_qdio_sbals_zero(&fsf_req->adapter->request_queue,
				    fsf_req->sbal_first, fsf_req->sbal_curr);
}


/**
 * zfcp_qdio_sbale_fill - set address and lenght in current SBALE
 *	on request_queue
 */
static inline void
zfcp_qdio_sbale_fill(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
		     void *addr, int length)
{
	volatile struct qdio_buffer_element *sbale;

	sbale = zfcp_qdio_sbale_curr(fsf_req);
	sbale->addr = addr;
	sbale->length = length;
}

/**
 * zfcp_qdio_sbals_from_segment - map memory segment to SBALE(s)
 * @fsf_req: request to be processed
 * @sbtype: SBALE flags
 * @start_addr: address of memory segment
 * @total_length: length of memory segment
 *
 * Alignment and length of the segment determine how many SBALEs are needed
 * for the memory segment.
 */
static inline int
zfcp_qdio_sbals_from_segment(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
			     void *start_addr, unsigned long total_length)
{
	unsigned long remaining, length;
	void *addr;

	/* split segment up heeding page boundaries */
	for (addr = start_addr, remaining = total_length; remaining > 0;
	     addr += length, remaining -= length) {
		/* get next free SBALE for new piece */
		if (NULL == zfcp_qdio_sbale_next(fsf_req, sbtype)) {
			/* no SBALE left, clean up and leave */
			zfcp_qdio_sbals_wipe(fsf_req);
			return -EINVAL;
		}
		/* calculate length of new piece */
		length = min(remaining,
			     (PAGE_SIZE - ((unsigned long) addr &
					   (PAGE_SIZE - 1))));
		/* fill current SBALE with calculated piece */
		zfcp_qdio_sbale_fill(fsf_req, sbtype, addr, length);
	}
	return total_length;
}


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

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

	/* set storage-block type for current SBAL */
	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
	sbale->flags |= sbtype;

	/* process all segements of scatter-gather list */
	for (sg_index = 0, sg_segment = sg, bytes = 0;
	     sg_index < sg_count;
	     sg_index++, sg_segment++) {
		retval = zfcp_qdio_sbals_from_segment(
				fsf_req,
				sbtype,
				zfcp_sg_to_address(sg_segment),
				sg_segment->length);
		if (retval < 0) {
			bytes = retval;
			goto out;
		} else
                        bytes += retval;
	}
	/* 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;
out:
	return bytes;
}


/**
 * zfcp_qdio_sbals_from_buffer - fill SBALs from buffer
 * @fsf_req: request to be processed
 * @sbtype: SBALE flags
 * @buffer: data buffer
 * @length: length of buffer
 * @max_sbals: upper bound for number of SBALs to be used
 */
static inline int
zfcp_qdio_sbals_from_buffer(struct zfcp_fsf_req *fsf_req, unsigned long sbtype,
			    void *buffer, unsigned long length, int max_sbals)
{
	struct scatterlist sg_segment;

	zfcp_address_to_sg(buffer, &sg_segment);
	sg_segment.length = length;

	return zfcp_qdio_sbals_from_sg(fsf_req, sbtype, &sg_segment, 1,
                                       max_sbals);
}


/**
 * zfcp_qdio_sbals_from_scsicmnd - fill SBALs from scsi command
 * @fsf_req: request to be processed
 * @sbtype: SBALE flags
 * @scsi_cmnd: either scatter-gather list or buffer contained herein is used
 *	to fill SBALs
 */
inline int
zfcp_qdio_sbals_from_scsicmnd(struct zfcp_fsf_req *fsf_req,
			      unsigned long sbtype, struct scsi_cmnd *scsi_cmnd)
{
	if (scsi_cmnd->use_sg) {
		return zfcp_qdio_sbals_from_sg(fsf_req,	sbtype,
                                               (struct scatterlist *)
                                               scsi_cmnd->request_buffer,
                                               scsi_cmnd->use_sg,
                                               ZFCP_MAX_SBALS_PER_REQ);
	} else {
                return zfcp_qdio_sbals_from_buffer(fsf_req, sbtype,
                                                   scsi_cmnd->request_buffer,
                                                   scsi_cmnd->request_bufflen,
                                                   ZFCP_MAX_SBALS_PER_REQ);
	}
}

/**
 * zfcp_qdio_determine_pci - set PCI flag in first SBALE on qdio queue if needed
 */
int
zfcp_qdio_determine_pci(struct zfcp_qdio_queue *req_queue,
			struct zfcp_fsf_req *fsf_req)
{
	int new_distance_from_int;
	int pci_pos;
	volatile struct qdio_buffer_element *sbale;

	new_distance_from_int = req_queue->distance_from_int +
                fsf_req->sbal_number;

	if (unlikely(new_distance_from_int >= ZFCP_QDIO_PCI_INTERVAL)) {
		new_distance_from_int %= ZFCP_QDIO_PCI_INTERVAL;
                pci_pos  = fsf_req->sbal_first;
		pci_pos += fsf_req->sbal_number;
		pci_pos -= new_distance_from_int;
		pci_pos -= 1;
		pci_pos %= QDIO_MAX_BUFFERS_PER_Q;
		sbale = zfcp_qdio_sbale_req(fsf_req, pci_pos, 0);
		sbale->flags |= SBAL_FLAGS0_PCI;
	}
	return new_distance_from_int;
}

/*
 * function:	zfcp_zero_sbals
 *
 * purpose:	zeros specified range of SBALs
 *
 * returns:
 */
void
zfcp_qdio_zero_sbals(struct qdio_buffer *buf[], int first, int clean_count)
{
	int cur_pos;
	int index;

	for (cur_pos = first; cur_pos < (first + clean_count); cur_pos++) {
		index = cur_pos % QDIO_MAX_BUFFERS_PER_Q;
		memset(buf[index], 0, sizeof (struct qdio_buffer));
		ZFCP_LOG_TRACE("zeroing BUFFER %d at address %p\n",
			       index, buf[index]);
	}
}

#undef ZFCP_LOG_AREA