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target: Remove unnecessary se_task members

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This is a squashed version of the following unnecessary se_task structure
member removal patches:

target: remove the task_execute_queue field in se_task

    Instead of using a separate flag we can simply do list_emptry checks
    on t_execute_list if we make sure to always use list_del_init to remove
    a task from the list.  Also factor some duplicate code into a new
    __transport_remove_task_from_execute_queue helper.

target: remove the read-only task_no field in se_task

    The task_no field never was initialized and only used in debug printks,
    so kill it.

target: remove the task_padded_sg field in se_task

    This field is only check in one place and not actually needed there.

    Rationale:
    - transport_do_task_sg_chain asserts that we have task_sg_chaining
      set early on
    - we only make use of the sg_prev_nents field we calculate based on it
      if there is another sg list that gets chained onto this one, which
      never happens for the last (or only) task.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Christoph Hellwig 2011-10-12 11:07:04 -04:00 committed by Nicholas Bellinger
parent 6c76bf951c
commit 04629b7bde
4 changed files with 28 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/target/target_core_tmr.c
View File

@ -226,11 +226,8 @@ static void core_tmr_drain_task_list(
/*
* Remove from task execute list before processing drain_task_list
*/
if (atomic_read(&task->task_execute_queue) != 0) {
list_del(&task->t_execute_list);
atomic_set(&task->task_execute_queue, 0);
atomic_dec(&dev->execute_tasks);
}
if (!list_empty(&task->t_execute_list))
__transport_remove_task_from_execute_queue(task, dev);
}
spin_unlock_irqrestore(&dev->execute_task_lock, flags);

59
drivers/target/target_core_transport.c
View File

@ -915,38 +915,36 @@ static void transport_add_tasks_from_cmd(struct se_cmd *cmd)
spin_lock_irqsave(&dev->execute_task_lock, flags);
list_for_each_entry(task, &cmd->t_task_list, t_list) {
if (atomic_read(&task->task_execute_queue))
if (!list_empty(&task->t_execute_list))
continue;
/*
* __transport_add_task_to_execute_queue() handles the
* SAM Task Attribute emulation if enabled
*/
__transport_add_task_to_execute_queue(task, task_prev, dev);
atomic_set(&task->task_execute_queue, 1);
task_prev = task;
}
spin_unlock_irqrestore(&dev->execute_task_lock, flags);
}
/* transport_remove_task_from_execute_queue():
*
*
*/
void __transport_remove_task_from_execute_queue(struct se_task *task,
struct se_device *dev)
{
list_del_init(&task->t_execute_list);
atomic_dec(&dev->execute_tasks);
}
void transport_remove_task_from_execute_queue(
struct se_task *task,
struct se_device *dev)
{
unsigned long flags;
if (atomic_read(&task->task_execute_queue) == 0) {
dump_stack();
if (WARN_ON(list_empty(&task->t_execute_list)))
return;
}
spin_lock_irqsave(&dev->execute_task_lock, flags);
list_del(&task->t_execute_list);
atomic_set(&task->task_execute_queue, 0);
atomic_dec(&dev->execute_tasks);
__transport_remove_task_from_execute_queue(task, dev);
spin_unlock_irqrestore(&dev->execute_task_lock, flags);
}
@ -1787,8 +1785,7 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
spin_lock_irqsave(&cmd->t_state_lock, flags);
list_for_each_entry_safe(task, task_tmp,
&cmd->t_task_list, t_list) {
pr_debug("task_no[%d] - Processing task %p\n",
task->task_no, task);
pr_debug("Processing task %p\n", task);
/*
* If the struct se_task has not been sent and is not active,
* remove the struct se_task from the execution queue.
@ -1799,8 +1796,7 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
transport_remove_task_from_execute_queue(task,
cmd->se_dev);
pr_debug("task_no[%d] - Removed from execute queue\n",
task->task_no);
pr_debug("Task %p removed from execute queue\n", task);
spin_lock_irqsave(&cmd->t_state_lock, flags);
continue;
}
@ -1814,17 +1810,15 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
spin_unlock_irqrestore(&cmd->t_state_lock,
flags);
pr_debug("task_no[%d] - Waiting to complete\n",
task->task_no);
pr_debug("Task %p waiting to complete\n", task);
wait_for_completion(&task->task_stop_comp);
pr_debug("task_no[%d] - Stopped successfully\n",
task->task_no);
pr_debug("Task %p stopped successfully\n", task);
spin_lock_irqsave(&cmd->t_state_lock, flags);
atomic_dec(&cmd->t_task_cdbs_left);
task->task_flags &= ~(TF_ACTIVE | TF_REQUEST_STOP);
} else {
pr_debug("task_no[%d] - Did nothing\n", task->task_no);
pr_debug("Task %p - did nothing\n", task);
ret++;
}
@ -2347,9 +2341,7 @@ check_depth:
}
task = list_first_entry(&dev->execute_task_list,
struct se_task, t_execute_list);
list_del(&task->t_execute_list);
atomic_set(&task->task_execute_queue, 0);
atomic_dec(&dev->execute_tasks);
__transport_remove_task_from_execute_queue(task, dev);
spin_unlock_irq(&dev->execute_task_lock);
atomic_dec(&dev->depth_left);
@ -2681,9 +2673,9 @@ static int transport_get_sense_data(struct se_cmd *cmd)
sense_buffer = dev->transport->get_sense_buffer(task);
if (!sense_buffer) {
pr_err("ITT[0x%08x]_TASK[%d]: Unable to locate"
pr_err("ITT[0x%08x]_TASK[%p]: Unable to locate"
" sense buffer for task with sense\n",
cmd->se_tfo->get_task_tag(cmd), task->task_no);
cmd->se_tfo->get_task_tag(cmd), task);
continue;
}
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
@ -3897,15 +3889,13 @@ void transport_do_task_sg_chain(struct se_cmd *cmd)
/*
* For the padded tasks, use the extra SGL vector allocated
* in transport_allocate_data_tasks() for the sg_prev_nents
* offset into sg_chain() above.. The last task of a
* multi-task list, or a single task will not have
* task->task_sg_padded set..
* offset into sg_chain() above.
*
* We do not need the padding for the last task (or a single
* task), but in that case we will never use the sg_prev_nents
* value below which would be incorrect.
*/
if (task->task_padded_sg)
sg_prev_nents = (task->task_sg_nents + 1);
else
sg_prev_nents = task->task_sg_nents;
sg_prev_nents = (task->task_sg_nents + 1);
sg_prev = task->task_sg;
}
/*
@ -3992,7 +3982,6 @@ static int transport_allocate_data_tasks(
*/
if (cmd->se_tfo->task_sg_chaining && (i < (task_count - 1))) {
task_sg_nents_padded = (task->task_sg_nents + 1);
task->task_padded_sg = 1;
} else
task_sg_nents_padded = task->task_sg_nents;

3
include/target/target_core_base.h
View File

@ -409,15 +409,12 @@ struct se_task {
u8 task_scsi_status;
u8 task_flags;
int task_error_status;
bool task_padded_sg;
unsigned long long task_lba;
u32 task_no;
u32 task_sectors;
u32 task_size;
enum dma_data_direction task_data_direction;
struct se_cmd *task_se_cmd;
struct completion task_stop_comp;
atomic_t task_execute_queue;
atomic_t task_state_active;
struct timer_list task_timer;
struct list_head t_list;

2
include/target/target_core_transport.h
View File

@ -135,6 +135,8 @@ extern void transport_add_task_to_execute_queue(struct se_task *,
struct se_device *);
extern void transport_remove_task_from_execute_queue(struct se_task *,
struct se_device *);
extern void __transport_remove_task_from_execute_queue(struct se_task *,
struct se_device *);
unsigned char *transport_dump_cmd_direction(struct se_cmd *);
extern void transport_dump_dev_state(struct se_device *, char *, int *);
extern void transport_dump_dev_info(struct se_device *, struct se_lun *,