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target: merge transport_new_cmd_obj into transport_generic_new_cmd
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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>
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Christoph Hellwig authored and Nicholas Bellinger committed Oct 24, 2011
1 parent 7c1c6af commit da0f761
Showing 1 changed file with 53 additions and 76 deletions.
129 changes: 53 additions & 76 deletions drivers/target/target_core_transport.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;

/*
Expand All @@ -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)
Expand All @@ -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);

Expand Down

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