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target: simplify command to task linkage
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Now that we only have a single task per command we can use a direct pointer
to it instead of list.

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 May 6, 2012
1 parent 4101f0a commit 785fdf7
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Showing 3 changed files with 45 additions and 89 deletions.
6 changes: 2 additions & 4 deletions drivers/target/target_core_tmr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -321,13 +321,11 @@ static void core_tmr_drain_task_list(
cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
cmd->t_task_cdb[0]);
pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
" t_task_cdbs: %d t_task_cdbs_left: %d"
" t_task_cdbs_sent: %d -- CMD_T_ACTIVE: %d"
" t_task_cdbs_left: %d"
" -- CMD_T_ACTIVE: %d"
" CMD_T_STOP: %d CMD_T_SENT: %d\n",
cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
cmd->t_task_list_num,
atomic_read(&cmd->t_task_cdbs_left),
atomic_read(&cmd->t_task_cdbs_sent),
(cmd->transport_state & CMD_T_ACTIVE) != 0,
(cmd->transport_state & CMD_T_STOP) != 0,
(cmd->transport_state & CMD_T_SENT) != 0);
Expand Down
121 changes: 42 additions & 79 deletions drivers/target/target_core_transport.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -453,9 +453,10 @@ static void transport_all_task_dev_remove_state(struct se_cmd *cmd)
if (!dev)
return;

list_for_each_entry(task, &cmd->t_task_list, t_list) {
task = cmd->t_task;
if (task) {
if (task->task_flags & TF_ACTIVE)
continue;
return;

spin_lock_irqsave(&dev->execute_task_lock, flags);
if (task->t_state_active) {
Expand Down Expand Up @@ -675,8 +676,7 @@ static void transport_remove_cmd_from_queue(struct se_cmd *cmd)
*/
void transport_complete_sync_cache(struct se_cmd *cmd, int good)
{
struct se_task *task = list_entry(cmd->t_task_list.next,
struct se_task, t_list);
struct se_task *task = cmd->t_task;

if (good) {
cmd->scsi_status = SAM_STAT_GOOD;
Expand Down Expand Up @@ -774,8 +774,7 @@ EXPORT_SYMBOL(transport_complete_task);

void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
{
struct se_task *task = list_entry(cmd->t_task_list.next,
struct se_task, t_list);
struct se_task *task = cmd->t_task;

task->task_scsi_status = scsi_status;
transport_complete_task(task, scsi_status == GOOD);
Expand All @@ -791,7 +790,6 @@ EXPORT_SYMBOL(target_complete_cmd);
*/
static inline int transport_add_task_check_sam_attr(
struct se_task *task,
struct se_task *task_prev,
struct se_device *dev)
{
/*
Expand All @@ -805,14 +803,10 @@ static inline int transport_add_task_check_sam_attr(
/*
* HEAD_OF_QUEUE attribute for received CDB, which means
* the first task that is associated with a struct se_cmd goes to
* head of the struct se_device->execute_task_list, and task_prev
* after that for each subsequent task
* head of the struct se_device->execute_task_list.
*/
if (task->task_se_cmd->sam_task_attr == MSG_HEAD_TAG) {
list_add(&task->t_execute_list,
(task_prev != NULL) ?
&task_prev->t_execute_list :
&dev->execute_task_list);
list_add(&task->t_execute_list, &dev->execute_task_list);

pr_debug("Set HEAD_OF_QUEUE for task CDB: 0x%02x"
" in execution queue\n",
Expand All @@ -834,12 +828,11 @@ static inline int transport_add_task_check_sam_attr(
*/
static void __transport_add_task_to_execute_queue(
struct se_task *task,
struct se_task *task_prev,
struct se_device *dev)
{
int head_of_queue;

head_of_queue = transport_add_task_check_sam_attr(task, task_prev, dev);
head_of_queue = transport_add_task_check_sam_attr(task, dev);
atomic_inc(&dev->execute_tasks);

if (task->t_state_active)
Expand All @@ -850,9 +843,7 @@ static void __transport_add_task_to_execute_queue(
* will always return head_of_queue == 0 here
*/
if (head_of_queue)
list_add(&task->t_state_list, (task_prev) ?
&task_prev->t_state_list :
&dev->state_task_list);
list_add(&task->t_state_list, &dev->state_task_list);
else
list_add_tail(&task->t_state_list, &dev->state_task_list);

Expand All @@ -870,7 +861,11 @@ static void transport_add_tasks_to_state_queue(struct se_cmd *cmd)
unsigned long flags;

spin_lock_irqsave(&cmd->t_state_lock, flags);
list_for_each_entry(task, &cmd->t_task_list, t_list) {
task = cmd->t_task;
if (task) {
if (task->task_flags & TF_ACTIVE)
goto out;

spin_lock(&dev->execute_task_lock);
if (!task->t_state_active) {
list_add_tail(&task->t_state_list,
Expand All @@ -883,24 +878,17 @@ static void transport_add_tasks_to_state_queue(struct se_cmd *cmd)
}
spin_unlock(&dev->execute_task_lock);
}
out:
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
}

static void __transport_add_tasks_from_cmd(struct se_cmd *cmd)
{
struct se_device *dev = cmd->se_dev;
struct se_task *task, *task_prev = NULL;
struct se_task *task;

list_for_each_entry(task, &cmd->t_task_list, t_list) {
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);
task_prev = task;
}
task = cmd->t_task;
if (task && list_empty(&task->t_execute_list))
__transport_add_task_to_execute_queue(task, cmd->se_dev);
}

static void transport_add_tasks_from_cmd(struct se_cmd *cmd)
Expand Down Expand Up @@ -1494,7 +1482,6 @@ void transport_init_se_cmd(
INIT_LIST_HEAD(&cmd->se_qf_node);
INIT_LIST_HEAD(&cmd->se_queue_node);
INIT_LIST_HEAD(&cmd->se_cmd_list);
INIT_LIST_HEAD(&cmd->t_task_list);
init_completion(&cmd->transport_lun_fe_stop_comp);
init_completion(&cmd->transport_lun_stop_comp);
init_completion(&cmd->t_transport_stop_comp);
Expand Down Expand Up @@ -1895,7 +1882,7 @@ bool target_stop_task(struct se_task *task, unsigned long *flags)

static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
{
struct se_task *task, *task_tmp;
struct se_task *task;
unsigned long flags;
int ret = 0;

Expand All @@ -1906,8 +1893,8 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
* No tasks remain in the execution queue
*/
spin_lock_irqsave(&cmd->t_state_lock, flags);
list_for_each_entry_safe(task, task_tmp,
&cmd->t_task_list, t_list) {
task = cmd->t_task;
if (task) {
pr_debug("Processing task %p\n", task);
/*
* If the struct se_task has not been sent and is not active,
Expand All @@ -1921,16 +1908,16 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)

pr_debug("Task %p removed from execute queue\n", task);
spin_lock_irqsave(&cmd->t_state_lock, flags);
continue;
goto out;
}

if (!target_stop_task(task, &flags)) {
pr_debug("Task %p - did nothing\n", task);
ret++;
}
}
out:
spin_unlock_irqrestore(&cmd->t_state_lock, flags);

return ret;
}

Expand All @@ -1947,12 +1934,10 @@ void transport_generic_request_failure(struct se_cmd *cmd)
pr_debug("-----[ i_state: %d t_state: %d scsi_sense_reason: %d\n",
cmd->se_tfo->get_cmd_state(cmd),
cmd->t_state, cmd->scsi_sense_reason);
pr_debug("-----[ t_tasks: %d t_task_cdbs_left: %d"
" t_task_cdbs_sent: %d t_task_cdbs_ex_left: %d --"
pr_debug("-----[ t_task_cdbs_left: %d"
" t_task_cdbs_ex_left: %d --"
" CMD_T_ACTIVE: %d CMD_T_STOP: %d CMD_T_SENT: %d\n",
cmd->t_task_list_num,
atomic_read(&cmd->t_task_cdbs_left),
atomic_read(&cmd->t_task_cdbs_sent),
atomic_read(&cmd->t_task_cdbs_ex_left),
(cmd->transport_state & CMD_T_ACTIVE) != 0,
(cmd->transport_state & CMD_T_STOP) != 0,
Expand Down Expand Up @@ -2212,11 +2197,7 @@ static int __transport_execute_tasks(struct se_device *dev, struct se_cmd *new_c
cmd = task->task_se_cmd;
spin_lock_irqsave(&cmd->t_state_lock, flags);
task->task_flags |= (TF_ACTIVE | TF_SENT);
atomic_inc(&cmd->t_task_cdbs_sent);

if (atomic_read(&cmd->t_task_cdbs_sent) ==
cmd->t_task_list_num)
cmd->transport_state |= CMD_T_SENT;
cmd->transport_state |= CMD_T_SENT;

spin_unlock_irqrestore(&cmd->t_state_lock, flags);

Expand Down Expand Up @@ -2458,7 +2439,7 @@ static int transport_get_sense_data(struct se_cmd *cmd)
{
unsigned char *buffer = cmd->sense_buffer, *sense_buffer = NULL;
struct se_device *dev = cmd->se_dev;
struct se_task *task = NULL, *task_tmp;
struct se_task *task = NULL;
unsigned long flags;
u32 offset = 0;

Expand All @@ -2473,23 +2454,23 @@ static int transport_get_sense_data(struct se_cmd *cmd)
return 0;
}

list_for_each_entry_safe(task, task_tmp,
&cmd->t_task_list, t_list) {
task = cmd->t_task;
if (task) {
if (!(task->task_flags & TF_HAS_SENSE))
continue;
goto out;

if (!dev->transport->get_sense_buffer) {
pr_err("dev->transport->get_sense_buffer"
" is NULL\n");
continue;
goto out;
}

sense_buffer = dev->transport->get_sense_buffer(task);
if (!sense_buffer) {
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);
continue;
goto out;
}
spin_unlock_irqrestore(&cmd->t_state_lock, flags);

Expand All @@ -2509,8 +2490,8 @@ static int transport_get_sense_data(struct se_cmd *cmd)
cmd->scsi_status);
return 0;
}
out:
spin_unlock_irqrestore(&cmd->t_state_lock, flags);

return -1;
}

Expand Down Expand Up @@ -3429,24 +3410,11 @@ static void target_complete_ok_work(struct work_struct *work)

static void transport_free_dev_tasks(struct se_cmd *cmd)
{
struct se_task *task, *task_tmp;
unsigned long flags;
LIST_HEAD(dispose_list);

spin_lock_irqsave(&cmd->t_state_lock, flags);
list_for_each_entry_safe(task, task_tmp,
&cmd->t_task_list, t_list) {
if (!(task->task_flags & TF_ACTIVE))
list_move_tail(&task->t_list, &dispose_list);
}
spin_unlock_irqrestore(&cmd->t_state_lock, flags);

while (!list_empty(&dispose_list)) {
task = list_first_entry(&dispose_list, struct se_task, t_list);
struct se_task *task;

list_del(&task->t_list);
task = cmd->t_task;
if (task && !(task->task_flags & TF_ACTIVE))
cmd->se_dev->transport->free_task(task);
}
}

static inline void transport_free_sgl(struct scatterlist *sgl, int nents)
Expand Down Expand Up @@ -3690,7 +3658,6 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
{
struct se_device *dev = cmd->se_dev;
struct se_task *task;
unsigned long flags;
int ret = 0;

/*
Expand Down Expand Up @@ -3742,7 +3709,6 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
goto out_fail;
}

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);
Expand All @@ -3751,16 +3717,13 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
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);
cmd->t_task = task;

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);
atomic_set(&cmd->t_task_cdbs_left, 1);
atomic_set(&cmd->t_task_cdbs_ex_left, 1);

/*
* For WRITEs, let the fabric know its buffer is ready..
Expand Down Expand Up @@ -4026,8 +3989,8 @@ static int transport_lun_wait_for_tasks(struct se_cmd *cmd, struct se_lun *lun)

ret = transport_stop_tasks_for_cmd(cmd);

pr_debug("ConfigFS: cmd: %p t_tasks: %d stop tasks ret:"
" %d\n", cmd, cmd->t_task_list_num, ret);
pr_debug("ConfigFS: cmd: %p stop tasks ret:"
" %d\n", cmd, ret);
if (!ret) {
pr_debug("ConfigFS: ITT[0x%08x] - stopping cmd....\n",
cmd->se_tfo->get_task_tag(cmd));
Expand Down
7 changes: 1 addition & 6 deletions include/target/target_core_base.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -492,7 +492,6 @@ struct se_task {
u16 task_flags;
u8 task_scsi_status;
enum dma_data_direction task_data_direction;
struct list_head t_list;
struct list_head t_execute_list;
struct list_head t_state_list;
bool t_state_active;
Expand Down Expand Up @@ -573,7 +572,6 @@ struct se_cmd {
atomic_t t_se_count;
atomic_t t_task_cdbs_left;
atomic_t t_task_cdbs_ex_left;
atomic_t t_task_cdbs_sent;
unsigned int transport_state;
#define CMD_T_ABORTED (1 << 0)
#define CMD_T_ACTIVE (1 << 1)
Expand All @@ -598,10 +596,7 @@ struct se_cmd {
struct scatterlist *t_bidi_data_sg;
unsigned int t_bidi_data_nents;

/* Used for BIDI READ */
struct list_head t_task_list;
u32 t_task_list_num;

struct se_task *t_task;
};

struct se_ua {
Expand Down

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