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@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
block/blk-iocost.c | 3 +--
block/blk-rq-qos.c | 14 +++++++-------
include/linux/wait.h | 6 ++++--
3 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 690ca99dfaca6..630895b4471c3 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2709,8 +2709,7 @@ 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 */
diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c
index 9b0aa7dd6779f..858ce69c04ece 100644
--- a/block/blk-rq-qos.c
+++ b/block/blk-rq-qos.c
@@ -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 {
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 8aa3372f21a08..b008ca42b5903 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -1206,14 +1206,16 @@ 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);
--
2.20.1
