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target: make more use of the task_flags field in se_task
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Replace various atomic_t variables that were mostly under t_state_lock
with new flags in task_flags.  Note that the execution error path
didn't take t_state_lock before, so add it there.

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 42bf829 commit 6c76bf9
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Showing 3 changed files with 43 additions and 44 deletions.
9 changes: 4 additions & 5 deletions drivers/target/target_core_tmr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -259,8 +259,8 @@ static void core_tmr_drain_task_list(
atomic_read(&cmd->t_transport_stop),
atomic_read(&cmd->t_transport_sent));

if (atomic_read(&task->task_active)) {
atomic_set(&task->task_stop, 1);
if (task->task_flags & TF_ACTIVE) {
task->task_flags |= TF_REQUEST_STOP;
spin_unlock_irqrestore(
&cmd->t_state_lock, flags);

Expand All @@ -269,11 +269,10 @@ static void core_tmr_drain_task_list(
wait_for_completion(&task->task_stop_comp);
pr_debug("LUN_RESET Completed task: %p shutdown for"
" dev: %p\n", task, dev);

spin_lock_irqsave(&cmd->t_state_lock, flags);
atomic_dec(&cmd->t_task_cdbs_left);

atomic_set(&task->task_active, 0);
atomic_set(&task->task_stop, 0);
task->task_flags &= ~(TF_ACTIVE | TF_REQUEST_STOP);
}
__transport_stop_task_timer(task, &flags);

Expand Down
64 changes: 32 additions & 32 deletions drivers/target/target_core_transport.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -440,7 +440,7 @@ static void transport_all_task_dev_remove_state(struct se_cmd *cmd)
return;

list_for_each_entry(task, &cmd->t_task_list, t_list) {
if (atomic_read(&task->task_active))
if (task->task_flags & TF_ACTIVE)
continue;

if (!atomic_read(&task->task_state_active))
Expand Down Expand Up @@ -718,7 +718,7 @@ void transport_complete_task(struct se_task *task, int success)
atomic_inc(&dev->depth_left);

spin_lock_irqsave(&cmd->t_state_lock, flags);
atomic_set(&task->task_active, 0);
task->task_flags &= ~TF_ACTIVE;

/*
* See if any sense data exists, if so set the TASK_SENSE flag.
Expand All @@ -737,14 +737,14 @@ void transport_complete_task(struct se_task *task, int success)
* See if we are waiting for outstanding struct se_task
* to complete for an exception condition
*/
if (atomic_read(&task->task_stop)) {
if (task->task_flags & TF_REQUEST_STOP) {
/*
* Decrement cmd->t_se_count if this task had
* previously thrown its timeout exception handler.
*/
if (atomic_read(&task->task_timeout)) {
if (task->task_flags & TF_TIMEOUT) {
atomic_dec(&cmd->t_se_count);
atomic_set(&task->task_timeout, 0);
task->task_flags &= ~TF_TIMEOUT;
}
spin_unlock_irqrestore(&cmd->t_state_lock, flags);

Expand All @@ -756,7 +756,7 @@ void transport_complete_task(struct se_task *task, int success)
* left counter to determine when the struct se_cmd is ready to be queued to
* the processing thread.
*/
if (atomic_read(&task->task_timeout)) {
if (task->task_flags & TF_TIMEOUT) {
if (!atomic_dec_and_test(
&cmd->t_task_cdbs_timeout_left)) {
spin_unlock_irqrestore(&cmd->t_state_lock,
Expand Down Expand Up @@ -1793,8 +1793,7 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
* If the struct se_task has not been sent and is not active,
* remove the struct se_task from the execution queue.
*/
if (!atomic_read(&task->task_sent) &&
!atomic_read(&task->task_active)) {
if (!(task->task_flags & (TF_ACTIVE | TF_SENT))) {
spin_unlock_irqrestore(&cmd->t_state_lock,
flags);
transport_remove_task_from_execute_queue(task,
Expand All @@ -1810,8 +1809,8 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
* If the struct se_task is active, sleep until it is returned
* from the plugin.
*/
if (atomic_read(&task->task_active)) {
atomic_set(&task->task_stop, 1);
if (task->task_flags & TF_ACTIVE) {
task->task_flags |= TF_REQUEST_STOP;
spin_unlock_irqrestore(&cmd->t_state_lock,
flags);

Expand All @@ -1823,9 +1822,7 @@ static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)

spin_lock_irqsave(&cmd->t_state_lock, flags);
atomic_dec(&cmd->t_task_cdbs_left);

atomic_set(&task->task_active, 0);
atomic_set(&task->task_stop, 0);
task->task_flags &= ~(TF_ACTIVE | TF_REQUEST_STOP);
} else {
pr_debug("task_no[%d] - Did nothing\n", task->task_no);
ret++;
Expand Down Expand Up @@ -2074,18 +2071,18 @@ static void transport_task_timeout_handler(unsigned long data)
pr_debug("transport task timeout fired! task: %p cmd: %p\n", task, cmd);

spin_lock_irqsave(&cmd->t_state_lock, flags);
if (task->task_flags & TF_STOP) {
if (task->task_flags & TF_TIMER_STOP) {
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
return;
}
task->task_flags &= ~TF_RUNNING;
task->task_flags &= ~TF_TIMER_RUNNING;

/*
* Determine if transport_complete_task() has already been called.
*/
if (!atomic_read(&task->task_active)) {
pr_debug("transport task: %p cmd: %p timeout task_active"
" == 0\n", task, cmd);
if (!(task->task_flags & TF_ACTIVE)) {
pr_debug("transport task: %p cmd: %p timeout !TF_ACTIVE\n",
task, cmd);
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
return;
}
Expand All @@ -2094,12 +2091,12 @@ static void transport_task_timeout_handler(unsigned long data)
atomic_inc(&cmd->t_transport_timeout);
cmd->t_tasks_failed = 1;

atomic_set(&task->task_timeout, 1);
task->task_flags |= TF_TIMEOUT;
task->task_error_status = PYX_TRANSPORT_TASK_TIMEOUT;
task->task_scsi_status = 1;

if (atomic_read(&task->task_stop)) {
pr_debug("transport task: %p cmd: %p timeout task_stop"
if (task->task_flags & TF_REQUEST_STOP) {
pr_debug("transport task: %p cmd: %p timeout TF_REQUEST_STOP"
" == 1\n", task, cmd);
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
complete(&task->task_stop_comp);
Expand Down Expand Up @@ -2129,7 +2126,7 @@ static void transport_start_task_timer(struct se_task *task)
struct se_device *dev = task->task_se_cmd->se_dev;
int timeout;

if (task->task_flags & TF_RUNNING)
if (task->task_flags & TF_TIMER_RUNNING)
return;
/*
* If the task_timeout is disabled, exit now.
Expand All @@ -2143,7 +2140,7 @@ static void transport_start_task_timer(struct se_task *task)
task->task_timer.data = (unsigned long) task;
task->task_timer.function = transport_task_timeout_handler;

task->task_flags |= TF_RUNNING;
task->task_flags |= TF_TIMER_RUNNING;
add_timer(&task->task_timer);
#if 0
pr_debug("Starting task timer for cmd: %p task: %p seconds:"
Expand All @@ -2158,17 +2155,17 @@ void __transport_stop_task_timer(struct se_task *task, unsigned long *flags)
{
struct se_cmd *cmd = task->task_se_cmd;

if (!task->task_flags & TF_RUNNING)
if (!(task->task_flags & TF_TIMER_RUNNING))
return;

task->task_flags |= TF_STOP;
task->task_flags |= TF_TIMER_STOP;
spin_unlock_irqrestore(&cmd->t_state_lock, *flags);

del_timer_sync(&task->task_timer);

spin_lock_irqsave(&cmd->t_state_lock, *flags);
task->task_flags &= ~TF_RUNNING;
task->task_flags &= ~TF_STOP;
task->task_flags &= ~TF_TIMER_RUNNING;
task->task_flags &= ~TF_TIMER_STOP;
}

static void transport_stop_all_task_timers(struct se_cmd *cmd)
Expand Down Expand Up @@ -2360,8 +2357,7 @@ static int __transport_execute_tasks(struct se_device *dev)
cmd = task->task_se_cmd;

spin_lock_irqsave(&cmd->t_state_lock, flags);
atomic_set(&task->task_active, 1);
atomic_set(&task->task_sent, 1);
task->task_flags |= (TF_ACTIVE | TF_SENT);
atomic_inc(&cmd->t_task_cdbs_sent);

if (atomic_read(&cmd->t_task_cdbs_sent) ==
Expand All @@ -2379,7 +2375,9 @@ static int __transport_execute_tasks(struct se_device *dev)
error = cmd->transport_emulate_cdb(cmd);
if (error != 0) {
cmd->transport_error_status = error;
atomic_set(&task->task_active, 0);
spin_lock_irqsave(&cmd->t_state_lock, flags);
task->task_flags &= ~TF_ACTIVE;
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
atomic_set(&cmd->transport_sent, 0);
transport_stop_tasks_for_cmd(cmd);
transport_generic_request_failure(cmd, dev, 0, 1);
Expand Down Expand Up @@ -2415,7 +2413,9 @@ static int __transport_execute_tasks(struct se_device *dev)

if (error != 0) {
cmd->transport_error_status = error;
atomic_set(&task->task_active, 0);
spin_lock_irqsave(&cmd->t_state_lock, flags);
task->task_flags &= ~TF_ACTIVE;
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
atomic_set(&cmd->transport_sent, 0);
transport_stop_tasks_for_cmd(cmd);
transport_generic_request_failure(cmd, dev, 0, 1);
Expand Down Expand Up @@ -3613,7 +3613,7 @@ static void transport_free_dev_tasks(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) {
if (atomic_read(&task->task_active))
if (task->task_flags & TF_ACTIVE)
continue;

kfree(task->task_sg_bidi);
Expand Down
14 changes: 7 additions & 7 deletions include/target/target_core_base.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -72,9 +72,13 @@ enum transport_tpg_type_table {
};

/* Used for generate timer flags */
enum timer_flags_table {
TF_RUNNING = 0x01,
TF_STOP = 0x02,
enum se_task_flags {
TF_ACTIVE = (1 << 0),
TF_SENT = (1 << 1),
TF_TIMEOUT = (1 << 2),
TF_REQUEST_STOP = (1 << 3),
TF_TIMER_RUNNING = (1 << 4),
TF_TIMER_STOP = (1 << 5),
};

/* Special transport agnostic struct se_cmd->t_states */
Expand Down Expand Up @@ -413,11 +417,7 @@ struct se_task {
enum dma_data_direction task_data_direction;
struct se_cmd *task_se_cmd;
struct completion task_stop_comp;
atomic_t task_active;
atomic_t task_execute_queue;
atomic_t task_timeout;
atomic_t task_sent;
atomic_t task_stop;
atomic_t task_state_active;
struct timer_list task_timer;
struct list_head t_list;
Expand Down

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