target: merge transport_new_cmd_obj into transport_generic_new_cmd

These are two fairly small functions, and merging them gives a much
more readable control flow, and opportunities for more useful comments.

It also moves all code related to resources allocation closer together
and allows to remove a forward declaration for transport_allocate_tasks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 53 insertions, 76 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 624d86ea083b..2fb6a2594429 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -77,10 +77,6 @@ static void transport_handle_queue_full(struct se_cmd *cmd,
                 struct se_device *dev);
 static void transport_direct_request_timeout(struct se_cmd *cmd);
 static void transport_free_dev_tasks(struct se_cmd *cmd);
-static u32 transport_allocate_tasks(struct se_cmd *cmd,
-                unsigned long long starting_lba,
-                enum dma_data_direction data_direction,
-                struct scatterlist *sgl, unsigned int nents);
 static int transport_generic_get_mem(struct se_cmd *cmd);
 static void transport_put_cmd(struct se_cmd *cmd);
 static void transport_remove_cmd_from_queue(struct se_cmd *cmd);
@@ -3666,62 +3662,6 @@ int transport_generic_map_mem_to_cmd(
 }
 EXPORT_SYMBOL(transport_generic_map_mem_to_cmd);
 
-static int transport_new_cmd_obj(struct se_cmd *cmd)
-{
-        struct se_device *dev = cmd->se_dev;
-        int set_counts = 1, rc, task_cdbs;
-
-        /*
-         * Setup any BIDI READ tasks and memory from
-         * cmd->t_mem_bidi_list so the READ struct se_tasks
-         * are queued first for the non pSCSI passthrough case.
-         */
-        if (cmd->t_bidi_data_sg &&
-            (dev->transport->transport_type != TRANSPORT_PLUGIN_PHBA_PDEV)) {
-                rc = transport_allocate_tasks(cmd,
-                                              cmd->t_task_lba,
-                                              DMA_FROM_DEVICE,
-                                              cmd->t_bidi_data_sg,
-                                              cmd->t_bidi_data_nents);
-                if (rc <= 0) {
-                        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
-                        cmd->scsi_sense_reason =
-                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-                        return -EINVAL;
-                }
-                atomic_inc(&cmd->t_fe_count);
-                atomic_inc(&cmd->t_se_count);
-                set_counts = 0;
-        }
-        /*
-         * Setup the tasks and memory from cmd->t_mem_list
-         * Note for BIDI transfers this will contain the WRITE payload
-         */
-        task_cdbs = transport_allocate_tasks(cmd,
-                                             cmd->t_task_lba,
-                                             cmd->data_direction,
-                                             cmd->t_data_sg,
-                                             cmd->t_data_nents);
-        if (task_cdbs <= 0) {
-                cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
-                cmd->scsi_sense_reason =
-                        TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-                return -EINVAL;
-        }
-
-        if (set_counts) {
-                atomic_inc(&cmd->t_fe_count);
-                atomic_inc(&cmd->t_se_count);
-        }
-
-        cmd->t_task_list_num = task_cdbs;
-
-        atomic_set(&cmd->t_task_cdbs_left, task_cdbs);
-        atomic_set(&cmd->t_task_cdbs_ex_left, task_cdbs);
-        atomic_set(&cmd->t_task_cdbs_timeout_left, task_cdbs);
-        return 0;
-}
-
 void *transport_kmap_first_data_page(struct se_cmd *cmd)
 {
         struct scatterlist *sg = cmd->t_data_sg;
@@ -4000,17 +3940,16 @@ static u32 transport_allocate_tasks(
 }
 
 
-/*       transport_generic_new_cmd(): Called from transport_processing_thread()
- *
- *       Allocate storage transport resources from a set of values predefined
- *       by transport_generic_cmd_sequencer() from the iSCSI Target RX process.
- *       Any non zero return here is treated as an "out of resource' op here.
+/*
+ * Allocate any required ressources to execute the command, and either place
+ * it on the execution queue if possible.  For writes we might not have the
+ * payload yet, thus notify the fabric via a call to ->write_pending instead.
  */
-        /*
-         * Generate struct se_task(s) and/or their payloads for this CDB.
-         */
 int transport_generic_new_cmd(struct se_cmd *cmd)
 {
+        struct se_device *dev = cmd->se_dev;
+        int task_cdbs;
+        int set_counts = 1;
         int ret = 0;
 
         /*
@@ -4024,16 +3963,49 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
                 if (ret < 0)
                         return ret;
         }
+
         /*
-         * Call transport_new_cmd_obj() to invoke transport_allocate_tasks() for
-         * control or data CDB types, and perform the map to backend subsystem
-         * code from SGL memory allocated here by transport_generic_get_mem(), or
-         * via pre-existing SGL memory setup explictly by fabric module code with
-         * transport_generic_map_mem_to_cmd().
+         * Setup any BIDI READ tasks and memory from
+         * cmd->t_mem_bidi_list so the READ struct se_tasks
+         * are queued first for the non pSCSI passthrough case.
          */
-        ret = transport_new_cmd_obj(cmd);
-        if (ret < 0)
-                return ret;
+        if (cmd->t_bidi_data_sg &&
+            (dev->transport->transport_type != TRANSPORT_PLUGIN_PHBA_PDEV)) {
+                ret = transport_allocate_tasks(cmd,
+                                              cmd->t_task_lba,
+                                              DMA_FROM_DEVICE,
+                                              cmd->t_bidi_data_sg,
+                                              cmd->t_bidi_data_nents);
+                if (ret <= 0)
+                        goto out_fail;
+
+                atomic_inc(&cmd->t_fe_count);
+                atomic_inc(&cmd->t_se_count);
+                set_counts = 0;
+        }
+        /*
+         * Setup the tasks and memory from cmd->t_mem_list
+         * Note for BIDI transfers this will contain the WRITE payload
+         */
+        task_cdbs = transport_allocate_tasks(cmd,
+                                             cmd->t_task_lba,
+                                             cmd->data_direction,
+                                             cmd->t_data_sg,
+                                             cmd->t_data_nents);
+        if (task_cdbs <= 0)
+                goto out_fail;
+
+        if (set_counts) {
+                atomic_inc(&cmd->t_fe_count);
+                atomic_inc(&cmd->t_se_count);
+        }
+
+        cmd->t_task_list_num = task_cdbs;
+
+        atomic_set(&cmd->t_task_cdbs_left, task_cdbs);
+        atomic_set(&cmd->t_task_cdbs_ex_left, task_cdbs);
+        atomic_set(&cmd->t_task_cdbs_timeout_left, task_cdbs);
+
         /*
          * For WRITEs, let the fabric know its buffer is ready..
          * This WRITE struct se_cmd (and all of its associated struct se_task's)
@@ -4051,6 +4023,11 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
          */
         transport_execute_tasks(cmd);
         return 0;
+
+out_fail:
+        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+        cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+        return -EINVAL;
 }
 EXPORT_SYMBOL(transport_generic_new_cmd);