target: always allocate a single task

Simply transport_generic_new_cmd to only allocate a single task.  For normal
unidirection commands nothing changes except that the code is a lot simpler
now.  Any BIDI support that used to work will stop now for the next few
patches at least.

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 087bbea..5267198 100644 (file)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1474,29 +1474,6 @@ static inline void transport_generic_prepare_cdb(
        }
 }
 
-static struct se_task *
-transport_generic_get_task(struct se_cmd *cmd,
-               enum dma_data_direction data_direction)
-{
-       struct se_task *task;
-       struct se_device *dev = cmd->se_dev;
-
-       task = dev->transport->alloc_task(cmd->t_task_cdb);
-       if (!task) {
-               pr_err("Unable to allocate struct se_task\n");
-               return NULL;
-       }
-
-       INIT_LIST_HEAD(&task->t_list);
-       INIT_LIST_HEAD(&task->t_execute_list);
-       INIT_LIST_HEAD(&task->t_state_list);
-       init_completion(&task->task_stop_comp);
-       task->task_se_cmd = cmd;
-       task->task_data_direction = data_direction;
-
-       return task;
-}
-
 static int transport_generic_cmd_sequencer(struct se_cmd *, unsigned char *);
 
 /*
@@ -3705,68 +3682,6 @@ out:
 }
 
 /*
- * Break up cmd into chunks transport can handle
- */
-static int
-transport_allocate_data_tasks(struct se_cmd *cmd,
-       enum dma_data_direction data_direction,
-       struct scatterlist *cmd_sg, unsigned int sgl_nents)
-{
-       struct se_device *dev = cmd->se_dev;
-       struct se_dev_attrib *attr = &dev->se_sub_dev->se_dev_attrib;
-       sector_t sectors;
-       struct se_task *task;
-       unsigned long flags;
-
-       if (transport_cmd_get_valid_sectors(cmd) < 0)
-               return -EINVAL;
-
-       sectors = DIV_ROUND_UP(cmd->data_length, attr->block_size);
-
-       BUG_ON(cmd->data_length % attr->block_size);
-       BUG_ON(sectors > attr->max_sectors);
-
-       task = transport_generic_get_task(cmd, data_direction);
-       if (!task)
-               return -ENOMEM;
-
-       task->task_sg = cmd_sg;
-       task->task_sg_nents = sgl_nents;
-
-       spin_lock_irqsave(&cmd->t_state_lock, flags);
-       list_add_tail(&task->t_list, &cmd->t_task_list);
-       spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-
-       return 1;
-}
-
-static int
-transport_allocate_control_task(struct se_cmd *cmd)
-{
-       struct se_task *task;
-       unsigned long flags;
-
-       /* Workaround for handling zero-length control CDBs */
-       if ((cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB) &&
-           !cmd->data_length)
-               return 0;
-
-       task = transport_generic_get_task(cmd, cmd->data_direction);
-       if (!task)
-               return -ENOMEM;
-
-       task->task_sg = cmd->t_data_sg;
-       task->task_sg_nents = cmd->t_data_nents;
-
-       spin_lock_irqsave(&cmd->t_state_lock, flags);
-       list_add_tail(&task->t_list, &cmd->t_task_list);
-       spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-
-       /* Success! Return number of tasks allocated */
-       return 1;
-}
-
-/*
  * Allocate any required resources to execute the command.  For writes we
  * might not have the payload yet, so notify the fabric via a call to
  * ->write_pending instead. Otherwise place it on the execution queue.
@@ -3774,8 +3689,8 @@ transport_allocate_control_task(struct se_cmd *cmd)
 int transport_generic_new_cmd(struct se_cmd *cmd)
 {
        struct se_device *dev = cmd->se_dev;
-       int task_cdbs, task_cdbs_bidi = 0;
-       int set_counts = 1;
+       struct se_task *task;
+       unsigned long flags;
        int ret = 0;
 
        /*
@@ -3790,35 +3705,9 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
                        goto out_fail;
        }
 
-       /*
-        * For BIDI command set up the read tasks first.
-        */
-       if (cmd->t_bidi_data_sg &&
-           dev->transport->transport_type != TRANSPORT_PLUGIN_PHBA_PDEV) {
-               BUG_ON(!(cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB));
-
-               task_cdbs_bidi = transport_allocate_data_tasks(cmd,
-                               DMA_FROM_DEVICE, cmd->t_bidi_data_sg,
-                               cmd->t_bidi_data_nents);
-               if (task_cdbs_bidi <= 0)
-                       goto out_fail;
-
-               atomic_inc(&cmd->t_fe_count);
-               atomic_inc(&cmd->t_se_count);
-               set_counts = 0;
-       }
-
-       if (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB) {
-               task_cdbs = transport_allocate_data_tasks(cmd,
-                                       cmd->data_direction, cmd->t_data_sg,
-                                       cmd->t_data_nents);
-       } else {
-               task_cdbs = transport_allocate_control_task(cmd);
-       }
-
-       if (task_cdbs < 0)
-               goto out_fail;
-       else if (!task_cdbs && (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB)) {
+       /* Workaround for handling zero-length control CDBs */
+       if ((cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB) &&
+           !cmd->data_length) {
                spin_lock_irq(&cmd->t_state_lock);
                cmd->t_state = TRANSPORT_COMPLETE;
                cmd->transport_state |= CMD_T_ACTIVE;
@@ -3836,12 +3725,40 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
                return 0;
        }
 
-       if (set_counts) {
-               atomic_inc(&cmd->t_fe_count);
-               atomic_inc(&cmd->t_se_count);
+       if (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB) {
+               struct se_dev_attrib *attr = &dev->se_sub_dev->se_dev_attrib;
+
+               if (transport_cmd_get_valid_sectors(cmd) < 0)
+                       return -EINVAL;
+
+               BUG_ON(cmd->data_length % attr->block_size);
+               BUG_ON(DIV_ROUND_UP(cmd->data_length, attr->block_size) >
+                       attr->max_sectors);
+       }
+
+       task = dev->transport->alloc_task(cmd->t_task_cdb);
+       if (!task) {
+               pr_err("Unable to allocate struct se_task\n");
+               goto out_fail;
        }
 
-       cmd->t_task_list_num = (task_cdbs + task_cdbs_bidi);
+       INIT_LIST_HEAD(&task->t_list);
+       INIT_LIST_HEAD(&task->t_execute_list);
+       INIT_LIST_HEAD(&task->t_state_list);
+       init_completion(&task->task_stop_comp);
+       task->task_se_cmd = cmd;
+       task->task_data_direction = cmd->data_direction;
+       task->task_sg = cmd->t_data_sg;
+       task->task_sg_nents = cmd->t_data_nents;
+
+       spin_lock_irqsave(&cmd->t_state_lock, flags);
+       list_add_tail(&task->t_list, &cmd->t_task_list);
+       spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+
+       atomic_inc(&cmd->t_fe_count);
+       atomic_inc(&cmd->t_se_count);
+
+       cmd->t_task_list_num = 1;
        atomic_set(&cmd->t_task_cdbs_left, cmd->t_task_list_num);
        atomic_set(&cmd->t_task_cdbs_ex_left, cmd->t_task_list_num);