Commit 36d03cb3 authored by Muchun Song's avatar Muchun Song Committed by Jens Axboe
Browse files

block: introduce init_wait_func() 



There is already a macro DEFINE_WAIT_FUNC() to declare a wait_queue_entry
with a specified waking function. But there is not a counterpart for
initializing one wait_queue_entry with a specified waking function. So
introducing init_wait_func() for this, which also could be used in iocost
and rq-qos. Using default_wake_function() in rq_qos_wait() to wake up
waiters, which could remove ->task field from rq_qos_wait_data.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarMuchun Song <songmuchun@bytedance.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250208090416.38642-1-songmuchun@bytedance.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3bee991f

block/blk-iocost.c

+1 −2
Original line number Diff line number Diff line
@@ -2718,8 +2718,7 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio) 
	 * All waiters are on iocg->waitq and the wait states are

	 * synchronized using waitq.lock.

	 */

	init_waitqueue_func_entry(&wait.wait, iocg_wake_fn);

	wait.wait.private = current;

	init_wait_func(&wait.wait, iocg_wake_fn);

	wait.bio = bio;

	wait.abs_cost = abs_cost;

	wait.committed = false;	/* will be set true by waker */

block/blk-rq-qos.c

+7 −7
Original line number Diff line number Diff line
@@ -196,7 +196,6 @@ bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle) 


struct rq_qos_wait_data {

	struct wait_queue_entry wq;

	struct task_struct *task;

	struct rq_wait *rqw;

	acquire_inflight_cb_t *cb;

	void *private_data;
@@ -218,7 +217,12 @@ static int rq_qos_wake_function(struct wait_queue_entry *curr, 
		return -1;



	data->got_token = true;

	wake_up_process(data->task);

	/*

	 * autoremove_wake_function() removes the wait entry only when it

	 * actually changed the task state. We want the wait always removed.

	 * Remove explicitly and use default_wake_function().

	 */

	default_wake_function(curr, mode, wake_flags, key);

	list_del_init_careful(&curr->entry);

	return 1;

}
@@ -244,11 +248,6 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data, 
		 cleanup_cb_t *cleanup_cb)

{

	struct rq_qos_wait_data data = {

		.wq = {

			.func	= rq_qos_wake_function,

			.entry	= LIST_HEAD_INIT(data.wq.entry),

		},

		.task = current,

		.rqw = rqw,

		.cb = acquire_inflight_cb,

		.private_data = private_data,
@@ -259,6 +258,7 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data, 
	if (!has_sleeper && acquire_inflight_cb(rqw, private_data))

		return;



	init_wait_func(&data.wq, rq_qos_wake_function);

	has_sleeper = !prepare_to_wait_exclusive(&rqw->wait, &data.wq,

						 TASK_UNINTERRUPTIBLE);

	do {

include/linux/wait.h

+4 −2
Original line number Diff line number Diff line
@@ -1207,14 +1207,16 @@ int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, i 


#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)



#define init_wait(wait)								\

#define init_wait_func(wait, function)						\

	do {									\

		(wait)->private = current;					\

		(wait)->func = autoremove_wake_function;			\

		(wait)->func = function;					\

		INIT_LIST_HEAD(&(wait)->entry);					\

		(wait)->flags = 0;						\

	} while (0)



#define init_wait(wait)	init_wait_func(wait, autoremove_wake_function)



typedef int (*task_call_f)(struct task_struct *p, void *arg);

extern int task_call_func(struct task_struct *p, task_call_f func, void *arg);