Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 868 insertions, 0 deletions

diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
new file mode 100644
index 000000000000..06e862d7bc90
--- /dev/null
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -0,0 +1,868 @@
+/*
+ * linux/drivers/s390/scsi/zfcp_qdio.c
+ *
+ * FCP adapter driver for IBM eServer zSeries
+ *
+ * QDIO related routines
+ *
+ * (C) Copyright IBM Corp. 2002, 2004
+ *
+ * Authors:
+ *      Martin Peschke <mpeschke@de.ibm.com>
+ *      Raimund Schroeder <raimund.schroeder@de.ibm.com>
+ *      Wolfgang Taphorn
+ *      Heiko Carstens <heiko.carstens@de.ibm.com>
+ *      Andreas Herrmann <aherrman@de.ibm.com>
+ *
+ * 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; either version 2, or (at your option)
+ * any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#define ZFCP_QDIO_C_REVISION "$Revision: 1.20 $"
+
+#include "zfcp_ext.h"
+
+static inline void zfcp_qdio_sbal_limit(struct zfcp_fsf_req *, int);
+static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_get
+        (struct zfcp_qdio_queue *, int, int);
+static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_resp
+        (struct zfcp_fsf_req *, int, int);
+static inline volatile struct qdio_buffer_element *zfcp_qdio_sbal_chain
+        (struct zfcp_fsf_req *, unsigned long);
+static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_next
+        (struct zfcp_fsf_req *, unsigned long);
+static inline int zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *, int, int);
+static inline int zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *);
+static inline void zfcp_qdio_sbale_fill
+        (struct zfcp_fsf_req *, unsigned long, void *, int);
+static inline int zfcp_qdio_sbals_from_segment
+        (struct zfcp_fsf_req *, unsigned long, void *, unsigned long);
+static inline int zfcp_qdio_sbals_from_buffer
+        (struct zfcp_fsf_req *, unsigned long, void *, unsigned long, int);
+
+static qdio_handler_t zfcp_qdio_request_handler;
+static qdio_handler_t zfcp_qdio_response_handler;
+static int zfcp_qdio_handler_error_check(struct zfcp_adapter *,
+                                         unsigned int,
+                                         unsigned int, unsigned int);
+
+#define ZFCP_LOG_AREA                   ZFCP_LOG_AREA_QDIO
+
+/*
+ * Allocates BUFFER memory to each of the pointers of the qdio_buffer_t 
+ * array in the adapter struct.
+ * Cur_buf is the pointer array and count can be any number of required 
+ * buffers, the page-fitting arithmetic is done entirely within this funciton.
+ *
+ * returns:     number of buffers allocated
+ * locks:       must only be called with zfcp_data.config_sema taken
+ */
+static int
+zfcp_qdio_buffers_enqueue(struct qdio_buffer **cur_buf, int count)
+{
+        int buf_pos;
+        int qdio_buffers_per_page;
+        int page_pos = 0;
+        struct qdio_buffer *first_in_page = NULL;
+
+        qdio_buffers_per_page = PAGE_SIZE / sizeof (struct qdio_buffer);
+        ZFCP_LOG_TRACE("buffers_per_page=%d\n", qdio_buffers_per_page);
+
+        for (buf_pos = 0; buf_pos < count; buf_pos++) {
+                if (page_pos == 0) {
+                        cur_buf[buf_pos] = (struct qdio_buffer *)
+                            get_zeroed_page(GFP_KERNEL);
+                        if (cur_buf[buf_pos] == NULL) {
+                                ZFCP_LOG_INFO("error: allocation of "
+                                              "QDIO buffer failed \n");
+                                goto out;
+                        }
+                        first_in_page = cur_buf[buf_pos];
+                } else {
+                        cur_buf[buf_pos] = first_in_page + page_pos;
+
+                }
+                /* was initialised to zero */
+                page_pos++;
+                page_pos %= qdio_buffers_per_page;
+        }
+ out:
+        return buf_pos;
+}
+
+/*
+ * Frees BUFFER memory for each of the pointers of the struct qdio_buffer array
+ * in the adapter struct cur_buf is the pointer array and count can be any
+ * number of buffers in the array that should be freed starting from buffer 0
+ *
+ * locks:       must only be called with zfcp_data.config_sema taken
+ */
+static void
+zfcp_qdio_buffers_dequeue(struct qdio_buffer **cur_buf, int count)
+{
+        int buf_pos;
+        int qdio_buffers_per_page;
+
+        qdio_buffers_per_page = PAGE_SIZE / sizeof (struct qdio_buffer);
+        ZFCP_LOG_TRACE("buffers_per_page=%d\n", qdio_buffers_per_page);
+
+        for (buf_pos = 0; buf_pos < count; buf_pos += qdio_buffers_per_page)
+                free_page((unsigned long) cur_buf[buf_pos]);
+        return;
+}
+
+/* locks:       must only be called with zfcp_data.config_sema taken */
+int
+zfcp_qdio_allocate_queues(struct zfcp_adapter *adapter)
+{
+        int buffer_count;
+        int retval = 0;
+
+        buffer_count =
+            zfcp_qdio_buffers_enqueue(&(adapter->request_queue.buffer[0]),
+                                      QDIO_MAX_BUFFERS_PER_Q);
+        if (buffer_count < QDIO_MAX_BUFFERS_PER_Q) {
+                ZFCP_LOG_DEBUG("only %d QDIO buffers allocated for request "
+                               "queue\n", buffer_count);
+                zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
+                                          buffer_count);
+                retval = -ENOMEM;
+                goto out;
+        }
+
+        buffer_count =
+            zfcp_qdio_buffers_enqueue(&(adapter->response_queue.buffer[0]),
+                                      QDIO_MAX_BUFFERS_PER_Q);
+        if (buffer_count < QDIO_MAX_BUFFERS_PER_Q) {
+                ZFCP_LOG_DEBUG("only %d QDIO buffers allocated for response "
+                               "queue", buffer_count);
+                zfcp_qdio_buffers_dequeue(&(adapter->response_queue.buffer[0]),
+                                          buffer_count);
+                ZFCP_LOG_TRACE("freeing request_queue buffers\n");
+                zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
+                                          QDIO_MAX_BUFFERS_PER_Q);
+                retval = -ENOMEM;
+                goto out;
+        }
+ out:
+        return retval;
+}
+
+/* locks:       must only be called with zfcp_data.config_sema taken */
+void
+zfcp_qdio_free_queues(struct zfcp_adapter *adapter)
+{
+        ZFCP_LOG_TRACE("freeing request_queue buffers\n");
+        zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
+                                  QDIO_MAX_BUFFERS_PER_Q);
+
+        ZFCP_LOG_TRACE("freeing response_queue buffers\n");
+        zfcp_qdio_buffers_dequeue(&(adapter->response_queue.buffer[0]),
+                                  QDIO_MAX_BUFFERS_PER_Q);
+}
+
+int
+zfcp_qdio_allocate(struct zfcp_adapter *adapter)
+{
+        struct qdio_initialize *init_data;
+
+        init_data = &adapter->qdio_init_data;
+
+        init_data->cdev = adapter->ccw_device;
+        init_data->q_format = QDIO_SCSI_QFMT;
+        memcpy(init_data->adapter_name, &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->min_input_threshold = ZFCP_MIN_INPUT_THRESHOLD;
+        init_data->max_input_threshold = ZFCP_MAX_INPUT_THRESHOLD;
+        init_data->min_output_threshold = ZFCP_MIN_OUTPUT_THRESHOLD;
+        init_data->max_output_threshold = ZFCP_MAX_OUTPUT_THRESHOLD;
+        init_data->no_input_qs = 1;
+        init_data->no_output_qs = 1;
+        init_data->input_handler = zfcp_qdio_response_handler;
+        init_data->output_handler = zfcp_qdio_request_handler;
+        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->response_queue.buffer);
+        init_data->output_sbal_addr_array =
+            (void **) (adapter->request_queue.buffer);
+
+        return qdio_allocate(init_data);
+}
+
+/*
+ * function:    zfcp_qdio_handler_error_check
+ *
+ * purpose:     called by the response handler to determine error condition
+ *
+ * returns:     error flag
+ *
+ */
+static inline int
+zfcp_qdio_handler_error_check(struct zfcp_adapter *adapter,
+                              unsigned int status,
+                              unsigned int qdio_error, unsigned int siga_error)
+{
+        int retval = 0;
+
+        if (ZFCP_LOG_CHECK(ZFCP_LOG_LEVEL_TRACE)) {
+                if (status & QDIO_STATUS_INBOUND_INT) {
+                        ZFCP_LOG_TRACE("status is"
+                                       " QDIO_STATUS_INBOUND_INT \n");
+                }
+                if (status & QDIO_STATUS_OUTBOUND_INT) {
+                        ZFCP_LOG_TRACE("status is"
+                                       " QDIO_STATUS_OUTBOUND_INT \n");
+                }
+        }                       // if (ZFCP_LOG_CHECK(ZFCP_LOG_LEVEL_TRACE))
+        if (unlikely(status & QDIO_STATUS_LOOK_FOR_ERROR)) {
+                retval = -EIO;
+
+                ZFCP_LOG_FLAGS(1, "QDIO_STATUS_LOOK_FOR_ERROR \n");
+
+                ZFCP_LOG_INFO("QDIO problem occurred (status=0x%x, "
+                              "qdio_error=0x%x, siga_error=0x%x)\n",
+                              status, qdio_error, siga_error);
+
+                if (status & QDIO_STATUS_ACTIVATE_CHECK_CONDITION) {
+                        ZFCP_LOG_FLAGS(2,
+                                       "QDIO_STATUS_ACTIVATE_CHECK_CONDITION\n");
+                }
+                if (status & QDIO_STATUS_MORE_THAN_ONE_QDIO_ERROR) {
+                        ZFCP_LOG_FLAGS(2,
+                                       "QDIO_STATUS_MORE_THAN_ONE_QDIO_ERROR\n");
+                }
+                if (status & QDIO_STATUS_MORE_THAN_ONE_SIGA_ERROR) {
+                        ZFCP_LOG_FLAGS(2,
+                                       "QDIO_STATUS_MORE_THAN_ONE_SIGA_ERROR\n");
+                }
+
+                if (siga_error & QDIO_SIGA_ERROR_ACCESS_EXCEPTION) {
+                        ZFCP_LOG_FLAGS(2, "QDIO_SIGA_ERROR_ACCESS_EXCEPTION\n");
+                }
+
+                if (siga_error & QDIO_SIGA_ERROR_B_BIT_SET) {
+                        ZFCP_LOG_FLAGS(2, "QDIO_SIGA_ERROR_B_BIT_SET\n");
+                }
+
+                switch (qdio_error) {
+                case 0:
+                        ZFCP_LOG_FLAGS(3, "QDIO_OK");
+                        break;
+                case SLSB_P_INPUT_ERROR:
+                        ZFCP_LOG_FLAGS(1, "SLSB_P_INPUT_ERROR\n");
+                        break;
+                case SLSB_P_OUTPUT_ERROR:
+                        ZFCP_LOG_FLAGS(1, "SLSB_P_OUTPUT_ERROR\n");
+                        break;
+                default:
+                        ZFCP_LOG_NORMAL("bug: unknown QDIO error 0x%x\n",
+                                        qdio_error);
+                        break;
+                }
+                /* Restarting IO on the failed adapter from scratch */
+                debug_text_event(adapter->erp_dbf, 1, "qdio_err");
+               /*
+                * Since we have been using this adapter, it is save to assume
+                * that it is not failed but recoverable. The card seems to
+                * report link-up events by self-initiated queue shutdown.
+                * That is why we need to clear the the link-down flag
+                * which is set again in case we have missed by a mile.
+                */
+               zfcp_erp_adapter_reopen(
+                       adapter, 
+                       ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
+                       ZFCP_STATUS_COMMON_ERP_FAILED);
+        }
+        return retval;
+}
+
+/*
+ * function:    zfcp_qdio_request_handler
+ *
+ * purpose:     is called by QDIO layer for completed SBALs in request queue
+ *
+ * returns:     (void)
+ */
+static void
+zfcp_qdio_request_handler(struct ccw_device *ccw_device,
+                          unsigned int status,
+                          unsigned int qdio_error,
+                          unsigned int siga_error,
+                          unsigned int queue_number,
+                          int first_element,
+                          int elements_processed,
+                          unsigned long int_parm)
+{
+        struct zfcp_adapter *adapter;
+        struct zfcp_qdio_queue *queue;
+
+        adapter = (struct zfcp_adapter *) int_parm;
+        queue = &adapter->request_queue;
+
+        ZFCP_LOG_DEBUG("adapter %s, first=%d, elements_processed=%d\n",
+                       zfcp_get_busid_by_adapter(adapter),
+                       first_element, elements_processed);
+
+        if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
+                                                   siga_error)))
+                goto out;
+        /*
+         * we stored address of struct zfcp_adapter  data structure
+         * associated with irq in int_parm
+         */
+
+        /* cleanup all SBALs being program-owned now */
+        zfcp_qdio_zero_sbals(queue->buffer, first_element, elements_processed);
+
+        /* increase free space in outbound queue */
+        atomic_add(elements_processed, &queue->free_count);
+        ZFCP_LOG_DEBUG("free_count=%d\n", atomic_read(&queue->free_count));
+        wake_up(&adapter->request_wq);
+        ZFCP_LOG_DEBUG("elements_processed=%d, free count=%d\n",
+                       elements_processed, atomic_read(&queue->free_count));
+ out:
+        return;
+}
+
+/*
+ * function:    zfcp_qdio_response_handler
+ *
+ * purpose:     is called by QDIO layer for completed SBALs in response queue
+ *
+ * returns:     (void)
+ */
+static void
+zfcp_qdio_response_handler(struct ccw_device *ccw_device,
+                           unsigned int status,
+                           unsigned int qdio_error,
+                           unsigned int siga_error,
+                           unsigned int queue_number,
+                           int first_element,
+                           int elements_processed,
+                           unsigned long int_parm)
+{
+        struct zfcp_adapter *adapter;
+        struct zfcp_qdio_queue *queue;
+        int buffer_index;
+        int i;
+        struct qdio_buffer *buffer;
+        int retval = 0;
+        u8 count;
+        u8 start;
+        volatile struct qdio_buffer_element *buffere = NULL;
+        int buffere_index;
+
+        adapter = (struct zfcp_adapter *) int_parm;
+        queue = &adapter->response_queue;
+
+        if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
+                                                   siga_error)))
+                goto out;
+
+        /*
+         * we stored address of struct zfcp_adapter  data structure
+         * associated with irq in int_parm
+         */
+
+        buffere = &(queue->buffer[first_element]->element[0]);
+        ZFCP_LOG_DEBUG("first BUFFERE flags=0x%x\n", buffere->flags);
+        /*
+         * go through all SBALs from input queue currently
+         * returned by QDIO layer
+         */
+
+        for (i = 0; i < elements_processed; i++) {
+
+                buffer_index = first_element + i;
+                buffer_index %= QDIO_MAX_BUFFERS_PER_Q;
+                buffer = queue->buffer[buffer_index];
+
+                /* go through all SBALEs of SBAL */
+                for (buffere_index = 0;
+                     buffere_index < QDIO_MAX_ELEMENTS_PER_BUFFER;
+                     buffere_index++) {
+
+                        /* look for QDIO request identifiers in SB */
+                        buffere = &buffer->element[buffere_index];
+                        retval = zfcp_qdio_reqid_check(adapter,
+                                                       (void *) buffere->addr);
+
+                        if (retval) {
+                                ZFCP_LOG_NORMAL("bug: unexpected inbound "
+                                                "packet on adapter %s "
+                                                "(reqid=0x%lx, "
+                                                "first_element=%d, "
+                                                "elements_processed=%d)\n",
+                                                zfcp_get_busid_by_adapter(adapter),
+                                                (unsigned long) buffere->addr,
+                                                first_element,
+                                                elements_processed);
+                                ZFCP_LOG_NORMAL("hex dump of inbound buffer "
+                                                "at address %p "
+                                                "(buffer_index=%d, "
+                                                "buffere_index=%d)\n", buffer,
+                                                buffer_index, buffere_index);
+                                ZFCP_HEX_DUMP(ZFCP_LOG_LEVEL_NORMAL,
+                                              (char *) buffer, SBAL_SIZE);
+                        }
+                        /*
+                         * A single used SBALE per inbound SBALE has been
+                         * implemented by QDIO so far. Hope they will
+                         * do some optimisation. Will need to change to
+                         * unlikely() then.
+                         */
+                        if (likely(buffere->flags & SBAL_FLAGS_LAST_ENTRY))
+                                break;
+                };
+
+                if (unlikely(!(buffere->flags & SBAL_FLAGS_LAST_ENTRY))) {
+                        ZFCP_LOG_NORMAL("bug: End of inbound data "
+                                        "not marked!\n");
+                }
+        }
+
+        /*
+         * put range of SBALs back to response queue
+         * (including SBALs which have already been free before)
+         */
+        count = atomic_read(&queue->free_count) + elements_processed;
+        start = queue->free_index;
+
+        ZFCP_LOG_TRACE("calling do_QDIO on adapter %s (flags=0x%x, "
+                       "queue_no=%i, index_in_queue=%i, count=%i, "
+                       "buffers=0x%lx\n",
+                       zfcp_get_busid_by_adapter(adapter),
+                       QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
+                       0, start, count, (unsigned long) &queue->buffer[start]);
+
+        retval = do_QDIO(ccw_device,
+                         QDIO_FLAG_SYNC_INPUT | QDIO_FLAG_UNDER_INTERRUPT,
+                         0, start, count, NULL);
+
+        if (unlikely(retval)) {
+                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;
+        int retval = 0;
+
+        /* invalid (per convention used in this driver) */
+        if (unlikely(!sbale_addr)) {
+                ZFCP_LOG_NORMAL("bug: invalid reqid\n");
+                retval = -EINVAL;
+                goto out;
+        }
+
+        /* valid request id and thus (hopefully :) valid fsf_req address */
+        fsf_req = (struct zfcp_fsf_req *) sbale_addr;
+
+        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);
+                retval = -EINVAL;
+                goto out;
+        }
+
+        ZFCP_LOG_TRACE("fsf_req at %p, QTCB at %p\n", fsf_req, fsf_req->qtcb);
+        if (likely(fsf_req->qtcb)) {
+                ZFCP_LOG_TRACE("hex dump of QTCB:\n");
+                ZFCP_HEX_DUMP(ZFCP_LOG_LEVEL_TRACE, (char *) fsf_req->qtcb,
+                              sizeof(struct fsf_qtcb));
+        }
+
+        /* finish the FSF request */
+        zfcp_fsf_req_complete(fsf_req);
+ out:
+        return retval;
+}
+
+/**
+ * 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