[PATCH 6/7] futex: make the vectored futex operations available

From: Jens Axboe
Date: Tue Jul 11 2023 - 20:47:35 EST


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@xxxxxxxxx>
---
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 ed5a7ccd2e99..b06e23c4900e 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -289,6 +289,11 @@ 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 dfd02ca5ecfa..b2b762acc997 100644
--- a/kernel/futex/waitwake.c
+++ b/kernel/futex/waitwake.c
@@ -358,7 +358,7 @@ 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
*
@@ -368,7 +368,7 @@ 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;

@@ -396,7 +396,7 @@ 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;
@@ -459,7 +459,7 @@ 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;

@@ -544,7 +544,7 @@ 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