[PATCH 09/10] futex: make the vectored futex operations available

Jens Axboe
2023-07-20T22:19:35Z

Rename unqueue_multiple() as futex_unqueue_multiple(), and make both
that and futex_wait_multiple_setup() available for external users. This
is in preparation for wiring up vectored waits in io_uring.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
kernel/futex/futex.h | 5 +++++
kernel/futex/waitwake.c | 10 +++++-----
2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index 3536d21adff9..faf84915acb2 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -332,6 +332,11 @@ extern int futex_parse_waitv(struct futex_vector *futexv,
unsigned int nr_futexes, futex_wake_fn *wake,
void *wake_data);

+extern int futex_wait_multiple_setup(struct futex_vector *vs, int count,
+ int *woken);
+
+extern int futex_unqueue_multiple(struct futex_vector *v, int count);
+
extern int futex_wait_multiple(struct futex_vector *vs, unsigned int count,
struct hrtimer_sleeper *to);

diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c
index 86f67f652b95..6c8fb7300558 100644
--- a/kernel/futex/waitwake.c
+++ b/kernel/futex/waitwake.c
@@ -369,7 +369,7 @@ void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q,
}

/**
- * unqueue_multiple - Remove various futexes from their hash bucket
+ * futex_unqueue_multiple - Remove various futexes from their hash bucket
* @v: The list of futexes to unqueue
* @count: Number of futexes in the list
*
@@ -379,7 +379,7 @@ void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q,
* - >=0 - Index of the last futex that was awoken;
* - -1 - No futex was awoken
*/
-static int unqueue_multiple(struct futex_vector *v, int count)
+int futex_unqueue_multiple(struct futex_vector *v, int count)
{
int ret = -1, i;

@@ -407,7 +407,7 @@ static int unqueue_multiple(struct futex_vector *v, int count)
* - 0 - Success
* - <0 - -EFAULT, -EWOULDBLOCK or -EINVAL
*/
-static int futex_wait_multiple_setup(struct futex_vector *vs, int count, int *woken)
+int futex_wait_multiple_setup(struct futex_vector *vs, int count, int *woken)
{
struct futex_hash_bucket *hb;
bool retry = false;
@@ -469,7 +469,7 @@ static int futex_wait_multiple_setup(struct futex_vector *vs, int count, int *wo
* was woken, we don't return error and return this index to
* userspace
*/
- *woken = unqueue_multiple(vs, i);
+ *woken = futex_unqueue_multiple(vs, i);
if (*woken >= 0)
return 1;

@@ -554,7 +554,7 @@ int futex_wait_multiple(struct futex_vector *vs, unsigned int count,

__set_current_state(TASK_RUNNING);

- ret = unqueue_multiple(vs, count);
+ ret = futex_unqueue_multiple(vs, count);
if (ret >= 0)
return ret;

--
2.40.1