sbp2: split sbp2_create_command_orb() for better readability

sbp2_create_command_orb() code cleanup:
 - add two helper functions to reduce nesting depth
 - omit the return value which was always ignored
 - remove unnecessary declaration from sb2.h

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jody McIntyre <scjody@modernduck.com>

2 files changed, 178 insertions, 184 deletions

diff --git a/drivers/ieee1394/sbp2.c b/drivers/ieee1394/sbp2.c
index 5b9d03e93514..14b0c35ee9a4 100644
--- a/drivers/ieee1394/sbp2.c
+++ b/drivers/ieee1394/sbp2.c
@@ -1707,26 +1707,184 @@ static int sbp2_agent_reset(struct scsi_id_instance_data *scsi_id, int wait)
         return 0;
 }
 
+static void sbp2_prep_command_orb_sg(struct sbp2_command_orb *orb,
+                                     struct sbp2scsi_host_info *hi,
+                                     struct sbp2_command_info *command,
+                                     unsigned int scsi_use_sg,
+                                     struct scatterlist *sgpnt,
+                                     u32 orb_direction,
+                                     enum dma_data_direction dma_dir)
+{
+        command->dma_dir = dma_dir;
+        orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
+        orb->misc |= ORB_SET_DIRECTION(orb_direction);
+
+        /* Special case if only one element (and less than 64KB in size) */
+        if ((scsi_use_sg == 1) &&
+            (sgpnt[0].length <= SBP2_MAX_SG_ELEMENT_LENGTH)) {
+
+                SBP2_DEBUG("Only one s/g element");
+                command->dma_size = sgpnt[0].length;
+                command->dma_type = CMD_DMA_PAGE;
+                command->cmd_dma = pci_map_page(hi->host->pdev,
+                                                sgpnt[0].page,
+                                                sgpnt[0].offset,
+                                                command->dma_size,
+                                                command->dma_dir);
+                SBP2_DMA_ALLOC("single page scatter element");
+
+                orb->data_descriptor_lo = command->cmd_dma;
+                orb->misc |= ORB_SET_DATA_SIZE(command->dma_size);
+
+        } else {
+                struct sbp2_unrestricted_page_table *sg_element =
+                                        &command->scatter_gather_element[0];
+                u32 sg_count, sg_len;
+                dma_addr_t sg_addr;
+                int i, count = pci_map_sg(hi->host->pdev, sgpnt, scsi_use_sg,
+                                          dma_dir);
+
+                SBP2_DMA_ALLOC("scatter list");
+
+                command->dma_size = scsi_use_sg;
+                command->sge_buffer = sgpnt;
+
+                /* use page tables (s/g) */
+                orb->misc |= ORB_SET_PAGE_TABLE_PRESENT(0x1);
+                orb->data_descriptor_lo = command->sge_dma;
+
+                /*
+                 * Loop through and fill out our sbp-2 page tables
+                 * (and split up anything too large)
+                 */
+                for (i = 0, sg_count = 0 ; i < count; i++, sgpnt++) {
+                        sg_len = sg_dma_len(sgpnt);
+                        sg_addr = sg_dma_address(sgpnt);
+                        while (sg_len) {
+                                sg_element[sg_count].segment_base_lo = sg_addr;
+                                if (sg_len > SBP2_MAX_SG_ELEMENT_LENGTH) {
+                                        sg_element[sg_count].length_segment_base_hi =
+                                                PAGE_TABLE_SET_SEGMENT_LENGTH(SBP2_MAX_SG_ELEMENT_LENGTH);
+                                        sg_addr += SBP2_MAX_SG_ELEMENT_LENGTH;
+                                        sg_len -= SBP2_MAX_SG_ELEMENT_LENGTH;
+                                } else {
+                                        sg_element[sg_count].length_segment_base_hi =
+                                                PAGE_TABLE_SET_SEGMENT_LENGTH(sg_len);
+                                        sg_len = 0;
+                                }
+                                sg_count++;
+                        }
+                }
+
+                /* Number of page table (s/g) elements */
+                orb->misc |= ORB_SET_DATA_SIZE(sg_count);
+
+                sbp2util_packet_dump(sg_element,
+                                     (sizeof(struct sbp2_unrestricted_page_table)) * sg_count,
+                                     "sbp2 s/g list", command->sge_dma);
+
+                /* Byte swap page tables if necessary */
+                sbp2util_cpu_to_be32_buffer(sg_element,
+                                            (sizeof(struct sbp2_unrestricted_page_table)) *
+                                            sg_count);
+        }
+}
+
+static void sbp2_prep_command_orb_no_sg(struct sbp2_command_orb *orb,
+                                        struct sbp2scsi_host_info *hi,
+                                        struct sbp2_command_info *command,
+                                        struct scatterlist *sgpnt,
+                                        u32 orb_direction,
+                                        unsigned int scsi_request_bufflen,
+                                        void *scsi_request_buffer,
+                                        enum dma_data_direction dma_dir)
+{
+        command->dma_dir = dma_dir;
+        command->dma_size = scsi_request_bufflen;
+        command->dma_type = CMD_DMA_SINGLE;
+        command->cmd_dma = pci_map_single(hi->host->pdev, scsi_request_buffer,
+                                          command->dma_size, command->dma_dir);
+        orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
+        orb->misc |= ORB_SET_DIRECTION(orb_direction);
+
+        SBP2_DMA_ALLOC("single bulk");
+
+        /*
+         * Handle case where we get a command w/o s/g enabled (but
+         * check for transfers larger than 64K)
+         */
+        if (scsi_request_bufflen <= SBP2_MAX_SG_ELEMENT_LENGTH) {
+
+                orb->data_descriptor_lo = command->cmd_dma;
+                orb->misc |= ORB_SET_DATA_SIZE(scsi_request_bufflen);
+
+        } else {
+                struct sbp2_unrestricted_page_table *sg_element =
+                        &command->scatter_gather_element[0];
+                u32 sg_count, sg_len;
+                dma_addr_t sg_addr;
+
+                /*
+                 * Need to turn this into page tables, since the
+                 * buffer is too large.
+                 */
+                orb->data_descriptor_lo = command->sge_dma;
+
+                /* Use page tables (s/g) */
+                orb->misc |= ORB_SET_PAGE_TABLE_PRESENT(0x1);
+
+                /*
+                 * fill out our sbp-2 page tables (and split up
+                 * the large buffer)
+                 */
+                sg_count = 0;
+                sg_len = scsi_request_bufflen;
+                sg_addr = command->cmd_dma;
+                while (sg_len) {
+                        sg_element[sg_count].segment_base_lo = sg_addr;
+                        if (sg_len > SBP2_MAX_SG_ELEMENT_LENGTH) {
+                                sg_element[sg_count].length_segment_base_hi =
+                                        PAGE_TABLE_SET_SEGMENT_LENGTH(SBP2_MAX_SG_ELEMENT_LENGTH);
+                                sg_addr += SBP2_MAX_SG_ELEMENT_LENGTH;
+                                sg_len -= SBP2_MAX_SG_ELEMENT_LENGTH;
+                        } else {
+                                sg_element[sg_count].length_segment_base_hi =
+                                        PAGE_TABLE_SET_SEGMENT_LENGTH(sg_len);
+                                sg_len = 0;
+                        }
+                        sg_count++;
+                }
+
+                /* Number of page table (s/g) elements */
+                orb->misc |= ORB_SET_DATA_SIZE(sg_count);
+
+                sbp2util_packet_dump(sg_element,
+                                     (sizeof(struct sbp2_unrestricted_page_table)) * sg_count,
+                                     "sbp2 s/g list", command->sge_dma);
+
+                /* Byte swap page tables if necessary */
+                sbp2util_cpu_to_be32_buffer(sg_element,
+                                            (sizeof(struct sbp2_unrestricted_page_table)) *
+                                             sg_count);
+        }
+}
+
 /*
  * This function is called to create the actual command orb and s/g list
  * out of the scsi command itself.
  */
-static int sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
-                                   struct sbp2_command_info *command,
-                                   unchar *scsi_cmd,
-                                   unsigned int scsi_use_sg,
-                                   unsigned int scsi_request_bufflen,
-                                   void *scsi_request_buffer,
-                                   enum dma_data_direction dma_dir)
+static void sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
+                                    struct sbp2_command_info *command,
+                                    unchar *scsi_cmd,
+                                    unsigned int scsi_use_sg,
+                                    unsigned int scsi_request_bufflen,
+                                    void *scsi_request_buffer,
+                                    enum dma_data_direction dma_dir)
 {
         struct sbp2scsi_host_info *hi = scsi_id->hi;
         struct scatterlist *sgpnt = (struct scatterlist *)scsi_request_buffer;
         struct sbp2_command_orb *command_orb = &command->command_orb;
-        struct sbp2_unrestricted_page_table *scatter_gather_element =
-                &command->scatter_gather_element[0];
-        u32 sg_count, sg_len, orb_direction;
-        dma_addr_t sg_addr;
-        int i;
+        u32 orb_direction;
 
         /*
          * Set-up our command ORB..
@@ -1753,186 +1911,29 @@ static int sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
                 orb_direction = ORB_DIRECTION_NO_DATA_TRANSFER;
         }
 
-        /*
-         * Set-up our pagetable stuff... unfortunately, this has become
-         * messier than I'd like. Need to clean this up a bit.   ;-)
-         */
+        /* Set-up our pagetable stuff */
         if (orb_direction == ORB_DIRECTION_NO_DATA_TRANSFER) {
-
                 SBP2_DEBUG("No data transfer");
-
-                /*
-                 * Handle no data transfer
-                 */
                 command_orb->data_descriptor_hi = 0x0;
                 command_orb->data_descriptor_lo = 0x0;
                 command_orb->misc |= ORB_SET_DIRECTION(1);
-
         } else if (scsi_use_sg) {
-
                 SBP2_DEBUG("Use scatter/gather");
-
-                /*
-                 * Special case if only one element (and less than 64KB in size)
-                 */
-                if ((scsi_use_sg == 1) && (sgpnt[0].length <= SBP2_MAX_SG_ELEMENT_LENGTH)) {
-
-                        SBP2_DEBUG("Only one s/g element");
-                        command->dma_dir = dma_dir;
-                        command->dma_size = sgpnt[0].length;
-                        command->dma_type = CMD_DMA_PAGE;
-                        command->cmd_dma = pci_map_page(hi->host->pdev,
-                                                        sgpnt[0].page,
-                                                        sgpnt[0].offset,
-                                                        command->dma_size,
-                                                        command->dma_dir);
-                        SBP2_DMA_ALLOC("single page scatter element");
-
-                        command_orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
-                        command_orb->data_descriptor_lo = command->cmd_dma;
-                        command_orb->misc |= ORB_SET_DATA_SIZE(command->dma_size);
-                        command_orb->misc |= ORB_SET_DIRECTION(orb_direction);
-
-                } else {
-                        int count = pci_map_sg(hi->host->pdev, sgpnt, scsi_use_sg, dma_dir);
-                        SBP2_DMA_ALLOC("scatter list");
-
-                        command->dma_size = scsi_use_sg;
-                        command->dma_dir = dma_dir;
-                        command->sge_buffer = sgpnt;
-
-                        /* use page tables (s/g) */
-                        command_orb->misc |= ORB_SET_PAGE_TABLE_PRESENT(0x1);
-                        command_orb->misc |= ORB_SET_DIRECTION(orb_direction);
-                        command_orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
-                        command_orb->data_descriptor_lo = command->sge_dma;
-
-                        /*
-                         * Loop through and fill out our sbp-2 page tables
-                         * (and split up anything too large)
-                         */
-                        for (i = 0, sg_count = 0 ; i < count; i++, sgpnt++) {
-                                sg_len = sg_dma_len(sgpnt);
-                                sg_addr = sg_dma_address(sgpnt);
-                                while (sg_len) {
-                                        scatter_gather_element[sg_count].segment_base_lo = sg_addr;
-                                        if (sg_len > SBP2_MAX_SG_ELEMENT_LENGTH) {
-                                                scatter_gather_element[sg_count].length_segment_base_hi =
-                                                        PAGE_TABLE_SET_SEGMENT_LENGTH(SBP2_MAX_SG_ELEMENT_LENGTH);
-                                                sg_addr += SBP2_MAX_SG_ELEMENT_LENGTH;
-                                                sg_len -= SBP2_MAX_SG_ELEMENT_LENGTH;
-                                        } else {
-                                                scatter_gather_element[sg_count].length_segment_base_hi =
-                                                        PAGE_TABLE_SET_SEGMENT_LENGTH(sg_len);
-                                                sg_len = 0;
-                                        }
-                                        sg_count++;
-                                }
-                        }
-
-                        /* Number of page table (s/g) elements */
-                        command_orb->misc |= ORB_SET_DATA_SIZE(sg_count);
-
-                        sbp2util_packet_dump(scatter_gather_element,
-                                             (sizeof(struct sbp2_unrestricted_page_table)) * sg_count,
-                                             "sbp2 s/g list", command->sge_dma);
-
-                        /*
-                         * Byte swap page tables if necessary
-                         */
-                        sbp2util_cpu_to_be32_buffer(scatter_gather_element,
-                                                    (sizeof(struct sbp2_unrestricted_page_table)) *
-                                                    sg_count);
-
-                }
-
+                sbp2_prep_command_orb_sg(command_orb, hi, command, scsi_use_sg,
+                                         sgpnt, orb_direction, dma_dir);
         } else {
-
                 SBP2_DEBUG("No scatter/gather");
-
-                command->dma_dir = dma_dir;
-                command->dma_size = scsi_request_bufflen;
-                command->dma_type = CMD_DMA_SINGLE;
-                command->cmd_dma =
-                    pci_map_single(hi->host->pdev, scsi_request_buffer,
-                                   command->dma_size, command->dma_dir);
-                SBP2_DMA_ALLOC("single bulk");
-
-                /*
-                 * Handle case where we get a command w/o s/g enabled (but
-                 * check for transfers larger than 64K)
-                 */
-                if (scsi_request_bufflen <= SBP2_MAX_SG_ELEMENT_LENGTH) {
-
-                        command_orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
-                        command_orb->data_descriptor_lo = command->cmd_dma;
-                        command_orb->misc |= ORB_SET_DATA_SIZE(scsi_request_bufflen);
-                        command_orb->misc |= ORB_SET_DIRECTION(orb_direction);
-
-                } else {
-                        /*
-                         * Need to turn this into page tables, since the
-                         * buffer is too large.
-                         */
-                        command_orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
-                        command_orb->data_descriptor_lo = command->sge_dma;
-
-                        /* Use page tables (s/g) */
-                        command_orb->misc |= ORB_SET_PAGE_TABLE_PRESENT(0x1);
-                        command_orb->misc |= ORB_SET_DIRECTION(orb_direction);
-
-                        /*
-                         * fill out our sbp-2 page tables (and split up
-                         * the large buffer)
-                         */
-                        sg_count = 0;
-                        sg_len = scsi_request_bufflen;
-                        sg_addr = command->cmd_dma;
-                        while (sg_len) {
-                                scatter_gather_element[sg_count].segment_base_lo = sg_addr;
-                                if (sg_len > SBP2_MAX_SG_ELEMENT_LENGTH) {
-                                        scatter_gather_element[sg_count].length_segment_base_hi =
-                                                PAGE_TABLE_SET_SEGMENT_LENGTH(SBP2_MAX_SG_ELEMENT_LENGTH);
-                                        sg_addr += SBP2_MAX_SG_ELEMENT_LENGTH;
-                                        sg_len -= SBP2_MAX_SG_ELEMENT_LENGTH;
-                                } else {
-                                        scatter_gather_element[sg_count].length_segment_base_hi =
-                                                PAGE_TABLE_SET_SEGMENT_LENGTH(sg_len);
-                                        sg_len = 0;
-                                }
-                                sg_count++;
-                        }
-
-                        /* Number of page table (s/g) elements */
-                        command_orb->misc |= ORB_SET_DATA_SIZE(sg_count);
-
-                        sbp2util_packet_dump(scatter_gather_element,
-                                             (sizeof(struct sbp2_unrestricted_page_table)) * sg_count,
-                                             "sbp2 s/g list", command->sge_dma);
-
-                        /*
-                         * Byte swap page tables if necessary
-                         */
-                        sbp2util_cpu_to_be32_buffer(scatter_gather_element,
-                                                    (sizeof(struct sbp2_unrestricted_page_table)) *
-                                                     sg_count);
-
-                }
-
+                sbp2_prep_command_orb_no_sg(command_orb, hi, command, sgpnt,
+                                            orb_direction, scsi_request_bufflen,
+                                            scsi_request_buffer, dma_dir);
         }
 
-        /*
-         * Byte swap command ORB if necessary
-         */
+        /* Byte swap command ORB if necessary */
         sbp2util_cpu_to_be32_buffer(command_orb, sizeof(struct sbp2_command_orb));
 
-        /*
-         * Put our scsi command in the command ORB
-         */
+        /* Put our scsi command in the command ORB */
         memset(command_orb->cdb, 0, 12);
         memcpy(command_orb->cdb, scsi_cmd, COMMAND_SIZE(*scsi_cmd));
-
-        return 0;
 }
 
 /*
diff --git a/drivers/ieee1394/sbp2.h b/drivers/ieee1394/sbp2.h
index 8e227c52b72f..900ea1d25e71 100644
--- a/drivers/ieee1394/sbp2.h
+++ b/drivers/ieee1394/sbp2.h
@@ -410,13 +410,6 @@ static int sbp2_logout_device(struct scsi_id_instance_data *scsi_id);
 static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid, int destid,
                                     quadlet_t *data, u64 addr, size_t length, u16 flags);
 static int sbp2_agent_reset(struct scsi_id_instance_data *scsi_id, int wait);
-static int sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
-                                   struct sbp2_command_info *command,
-                                   unchar *scsi_cmd,
-                                   unsigned int scsi_use_sg,
-                                   unsigned int scsi_request_bufflen,
-                                   void *scsi_request_buffer,
-                                   enum dma_data_direction dma_dir);
 static int sbp2_link_orb_command(struct scsi_id_instance_data *scsi_id,
                                  struct sbp2_command_info *command);
 static int sbp2_send_command(struct scsi_id_instance_data *scsi_id,