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>

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 624d86ea083bc51cfc9ea6d973695d9a2d371c49..2fb6a25944295501e87bc2ea24c90d104d9b69db 100644 (file)
--- 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);