public inbox for [email protected]
 help / color / mirror / Atom feed
From: Jens Axboe <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], [email protected], [email protected],
	Jens Axboe <[email protected]>
Subject: [PATCH 3/8] futex: abstract out a __futex_wake_mark() helper
Date: Thu, 28 Sep 2023 11:25:12 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Move the unqueue and lock_ptr clear into a helper that futex_wake_mark()
calls. Add it to the public functions as well, in preparation for using
it outside the core futex code.

Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
 kernel/futex/futex.h    |  1 +
 kernel/futex/waitwake.c | 33 ++++++++++++++++++++++-----------
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index 547f509b2c87..33835b81e0c3 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -219,6 +219,7 @@ extern int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags,
 			    struct futex_q *q, struct futex_hash_bucket **hb);
 extern void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q,
 				   struct hrtimer_sleeper *timeout);
+extern bool __futex_wake_mark(struct futex_q *q);
 extern void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q);
 
 extern int fault_in_user_writeable(u32 __user *uaddr);
diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c
index 35c6a637a4bb..6fcf5f723719 100644
--- a/kernel/futex/waitwake.c
+++ b/kernel/futex/waitwake.c
@@ -106,20 +106,11 @@
  * double_lock_hb() and double_unlock_hb(), respectively.
  */
 
-/*
- * The hash bucket lock must be held when this is called.
- * Afterwards, the futex_q must not be accessed. Callers
- * must ensure to later call wake_up_q() for the actual
- * wakeups to occur.
- */
-void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q)
+bool __futex_wake_mark(struct futex_q *q)
 {
-	struct task_struct *p = q->task;
-
 	if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex\n"))
-		return;
+		return false;
 
-	get_task_struct(p);
 	__futex_unqueue(q);
 	/*
 	 * The waiting task can free the futex_q as soon as q->lock_ptr = NULL
@@ -130,6 +121,26 @@ void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q)
 	 */
 	smp_store_release(&q->lock_ptr, NULL);
 
+	return true;
+}
+
+/*
+ * The hash bucket lock must be held when this is called.
+ * Afterwards, the futex_q must not be accessed. Callers
+ * must ensure to later call wake_up_q() for the actual
+ * wakeups to occur.
+ */
+void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q)
+{
+	struct task_struct *p = q->task;
+
+	get_task_struct(p);
+
+	if (!__futex_wake_mark(q)) {
+		put_task_struct(p);
+		return;
+	}
+
 	/*
 	 * Queue the task for later wakeup for after we've released
 	 * the hb->lock.
-- 
2.40.1


  parent reply	other threads:[~2023-09-28 17:25 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-28 17:25 [PATCHSET v6] Add io_uring futex/futexv support Jens Axboe
2023-09-28 17:25 ` [PATCH 1/8] futex: move FUTEX2_VALID_MASK to futex.h Jens Axboe
2023-09-28 17:25 ` [PATCH 2/8] futex: factor out the futex wake handling Jens Axboe
2023-09-28 17:25 ` Jens Axboe [this message]
2023-09-28 17:25 ` [PATCH 4/8] io_uring: add support for futex wake and wait Jens Axboe
2023-09-28 17:25 ` [PATCH 5/8] futex: add wake_data to struct futex_q Jens Axboe
2023-09-28 17:25 ` [PATCH 6/8] futex: make futex_parse_waitv() available as a helper Jens Axboe
2023-09-28 17:25 ` [PATCH 7/8] futex: make the vectored futex operations available Jens Axboe
2023-09-28 17:25 ` [PATCH 8/8] io_uring: add support for vectored futex waits Jens Axboe
2023-09-29  7:53 ` [PATCHSET v6] Add io_uring futex/futexv support Peter Zijlstra
2023-09-29  9:11   ` Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2023-09-21 18:29 [PATCHSET v5] " Jens Axboe
2023-09-21 18:29 ` [PATCH 3/8] futex: abstract out a __futex_wake_mark() helper Jens Axboe
2023-07-12 16:20 [PATCHSET v2 0/8] Add io_uring futex/futexv support Jens Axboe
2023-07-12 16:20 ` [PATCH 3/8] futex: abstract out a __futex_wake_mark() helper Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox