[PATCH 2/7] futex: factor out the futex wake handling

Jens Axboe
2023-07-12T00:47:21Z

In preparation for having another waker that isn't futex_wake_mark(),
add a wake handler in futex_q. No extra data is associated with the
handler outside of struct futex_q itself. futex_wake_mark() is defined as
the standard wakeup helper, now set through futex_q_init like other
defaults.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
kernel/futex/futex.h | 4 ++++
kernel/futex/requeue.c | 3 ++-
kernel/futex/waitwake.c | 6 +++---
3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index d2949fca37d1..8eaf1a5ce967 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -69,6 +69,9 @@ struct futex_pi_state {
union futex_key key;
} __randomize_layout;

+struct futex_q;
+typedef void (futex_wake_fn)(struct wake_q_head *wake_q, struct futex_q *q);
+
/**
* struct futex_q - The hashed futex queue entry, one per waiting task
* @list: priority-sorted list of tasks waiting on this futex
@@ -98,6 +101,7 @@ struct futex_q {

struct task_struct *task;
spinlock_t *lock_ptr;
+ futex_wake_fn *wake;
union futex_key key;
struct futex_pi_state *pi_state;
struct rt_mutex_waiter *rt_waiter;
diff --git a/kernel/futex/requeue.c b/kernel/futex/requeue.c
index cba8b1a6a4cc..e892bc6c41d8 100644
--- a/kernel/futex/requeue.c
+++ b/kernel/futex/requeue.c
@@ -58,6 +58,7 @@ enum {

const struct futex_q futex_q_init = {
/* list gets initialized in futex_queue()*/
+ .wake = futex_wake_mark,
.key = FUTEX_KEY_INIT,
.bitset = FUTEX_BITSET_MATCH_ANY,
.requeue_state = ATOMIC_INIT(Q_REQUEUE_PI_NONE),
@@ -591,7 +592,7 @@ int futex_requeue(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
/* Plain futexes just wake or requeue and are done */
if (!requeue_pi) {
if (++task_count <= nr_wake)
- futex_wake_mark(&wake_q, this);
+ this->wake(&wake_q, this);
else
requeue_futex(this, hb1, hb2, &key2);
continue;
diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c
index ba01b9408203..3471af87cb7d 100644
--- a/kernel/futex/waitwake.c
+++ b/kernel/futex/waitwake.c
@@ -174,7 +174,7 @@ int futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
if (!(this->bitset & bitset))
continue;

- futex_wake_mark(&wake_q, this);
+ this->wake(&wake_q, this);
if (++ret >= nr_wake)
break;
}
@@ -289,7 +289,7 @@ int futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
ret = -EINVAL;
goto out_unlock;
}
- futex_wake_mark(&wake_q, this);
+ this->wake(&wake_q, this);
if (++ret >= nr_wake)
break;
}
@@ -303,7 +303,7 @@ int futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
ret = -EINVAL;
goto out_unlock;
}
- futex_wake_mark(&wake_q, this);
+ this->wake(&wake_q, this);
if (++op_ret >= nr_wake2)
break;
}
--
2.40.1