Commit 65f27f38 authored by David Howells's avatar David Howells
Browse files

WorkStruct: Pass the work_struct pointer instead of context data 



Pass the work_struct pointer to the work function rather than context data.
The work function can use container_of() to work out the data.

For the cases where the container of the work_struct may go away the moment the
pending bit is cleared, it is made possible to defer the release of the
structure by deferring the clearing of the pending bit.

To make this work, an extra flag is introduced into the management side of the
work_struct.  This governs auto-release of the structure upon execution.

Ordinarily, the work queue executor would release the work_struct for further
scheduling or deallocation by clearing the pending bit prior to jumping to the
work function.  This means that, unless the driver makes some guarantee itself
that the work_struct won't go away, the work function may not access anything
else in the work_struct or its container lest they be deallocated..  This is a
problem if the auxiliary data is taken away (as done by the last patch).

However, if the pending bit is *not* cleared before jumping to the work
function, then the work function *may* access the work_struct and its container
with no problems.  But then the work function must itself release the
work_struct by calling work_release().

In most cases, automatic release is fine, so this is the default.  Special
initiators exist for the non-auto-release case (ending in _NAR).


Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>
parent 365970a1

arch/x86_64/kernel/mce.c

+3 −3
Original line number Diff line number Diff line
@@ -306,8 +306,8 @@ void mce_log_therm_throt_event(unsigned int cpu, __u64 status) 
 */



static int check_interval = 5 * 60; /* 5 minutes */

static void mcheck_timer(void *data);

static DECLARE_DELAYED_WORK(mcheck_work, mcheck_timer, NULL);

static void mcheck_timer(struct work_struct *work);

static DECLARE_DELAYED_WORK(mcheck_work, mcheck_timer);



static void mcheck_check_cpu(void *info)

{
@@ -315,7 +315,7 @@ static void mcheck_check_cpu(void *info) 
		do_machine_check(NULL, 0);

}



static void mcheck_timer(void *data)

static void mcheck_timer(struct work_struct *work)

{

	on_each_cpu(mcheck_check_cpu, NULL, 1, 1);

	schedule_delayed_work(&mcheck_work, check_interval * HZ);

arch/x86_64/kernel/smpboot.c

+7 −5
Original line number Diff line number Diff line
@@ -753,14 +753,16 @@ static int __cpuinit wakeup_secondary_via_INIT(int phys_apicid, unsigned int sta 
}



struct create_idle {

	struct work_struct work;

	struct task_struct *idle;

	struct completion done;

	int cpu;

};



void do_fork_idle(void *_c_idle)

void do_fork_idle(struct work_struct *work)

{

	struct create_idle *c_idle = _c_idle;

	struct create_idle *c_idle =

		container_of(work, struct create_idle, work);



	c_idle->idle = fork_idle(c_idle->cpu);

	complete(&c_idle->done);
@@ -775,10 +777,10 @@ static int __cpuinit do_boot_cpu(int cpu, int apicid) 
	int timeout;

	unsigned long start_rip;

	struct create_idle c_idle = {

		.work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),

		.cpu = cpu,

		.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),

	};

	DECLARE_WORK(work, do_fork_idle, &c_idle);



	/* allocate memory for gdts of secondary cpus. Hotplug is considered */

	if (!cpu_gdt_descr[cpu].address &&
@@ -825,9 +827,9 @@ static int __cpuinit do_boot_cpu(int cpu, int apicid) 
	 * thread.

	 */

	if (!keventd_up() || current_is_keventd())

		work.func(work.data);

		c_idle.work.func(&c_idle.work);

	else {

		schedule_work(&work);

		schedule_work(&c_idle.work);

		wait_for_completion(&c_idle.done);

	}

arch/x86_64/kernel/time.c

+2 −2
Original line number Diff line number Diff line
@@ -563,7 +563,7 @@ static unsigned int cpufreq_delayed_issched = 0; 
static unsigned int cpufreq_init = 0;

static struct work_struct cpufreq_delayed_get_work;



static void handle_cpufreq_delayed_get(void *v)

static void handle_cpufreq_delayed_get(struct work_struct *v)

{

	unsigned int cpu;

	for_each_online_cpu(cpu) {
@@ -639,7 +639,7 @@ static struct notifier_block time_cpufreq_notifier_block = { 


static int __init cpufreq_tsc(void)

{

	INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get, NULL);

	INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get);

	if (!cpufreq_register_notifier(&time_cpufreq_notifier_block,

				       CPUFREQ_TRANSITION_NOTIFIER))

		cpufreq_init = 1;

block/as-iosched.c

+4 −3
Original line number Diff line number Diff line
@@ -1274,9 +1274,10 @@ static void as_merged_requests(request_queue_t *q, struct request *req, 
 *

 * FIXME! dispatch queue is not a queue at all!

 */

static void as_work_handler(void *data)

static void as_work_handler(struct work_struct *work)

{

	struct request_queue *q = data;

	struct as_data *ad = container_of(work, struct as_data, antic_work);

	struct request_queue *q = ad->q;

	unsigned long flags;



	spin_lock_irqsave(q->queue_lock, flags);
@@ -1332,7 +1333,7 @@ static void *as_init_queue(request_queue_t *q, elevator_t *e) 
	ad->antic_timer.function = as_antic_timeout;

	ad->antic_timer.data = (unsigned long)q;

	init_timer(&ad->antic_timer);

	INIT_WORK(&ad->antic_work, as_work_handler, q);

	INIT_WORK(&ad->antic_work, as_work_handler);



	INIT_LIST_HEAD(&ad->fifo_list[REQ_SYNC]);

	INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);

block/cfq-iosched.c

+5 −3
Original line number Diff line number Diff line
@@ -1841,9 +1841,11 @@ queue_fail: 
	return 1;

}



static void cfq_kick_queue(void *data)

static void cfq_kick_queue(struct work_struct *work)

{

	request_queue_t *q = data;

	struct cfq_data *cfqd =

		container_of(work, struct cfq_data, unplug_work);

	request_queue_t *q = cfqd->queue;

	unsigned long flags;



	spin_lock_irqsave(q->queue_lock, flags);
@@ -1987,7 +1989,7 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) 
	cfqd->idle_class_timer.function = cfq_idle_class_timer;

	cfqd->idle_class_timer.data = (unsigned long) cfqd;



	INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);

	INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);



	cfqd->cfq_quantum = cfq_quantum;

	cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];

CRA Git | Maintained and supported by SUSTech CRA and CCSE