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From: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org,
	daniel@iogearbox.net, kafai@meta.com, kernel-team@meta.com,
	eddyz87@gmail.com, memxor@gmail.com
Cc: Mykyta Yatsenko <yatsenko@meta.com>
Subject: [PATCH RFC v1 3/5] bpf: factor out timer deletion helper
Date: Fri, 31 Oct 2025 21:58:33 +0000	[thread overview]
Message-ID: <20251031-timer_nolock-v1-3-bf8266d2fb20@meta.com> (raw)
In-Reply-To: <20251031-timer_nolock-v1-0-bf8266d2fb20@meta.com>

From: Mykyta Yatsenko <yatsenko@meta.com>

Move the timer deletion logic into a dedicated bpf_timer_delete()
helper so it can be reused by later patches.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
---
 kernel/bpf/helpers.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index d09c2b8989a123d6fd5a3b59efd40018c81d0149..2eb2369cae3ad34fd218387aa237140003cc1853 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1153,6 +1153,8 @@ enum bpf_async_type {
 
 static DEFINE_PER_CPU(struct bpf_hrtimer *, hrtimer_running);
 
+static void bpf_timer_delete(struct bpf_hrtimer *t);
+
 static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer)
 {
 	struct bpf_hrtimer *t = container_of(hrtimer, struct bpf_hrtimer, timer);
@@ -1576,18 +1578,10 @@ static struct bpf_async_cb *__bpf_async_cancel_and_free(struct bpf_async_kern *a
 	return cb;
 }
 
-/* This function is called by map_delete/update_elem for individual element and
- * by ops->map_release_uref when the user space reference to a map reaches zero.
- */
-void bpf_timer_cancel_and_free(void *val)
+static void bpf_timer_delete(struct bpf_hrtimer *t)
 {
-	struct bpf_hrtimer *t;
-
-	t = (struct bpf_hrtimer *)__bpf_async_cancel_and_free(val);
-
-	if (!t)
-		return;
-	/* We check that bpf_map_delete/update_elem() was called from timer
+	/*
+	 * We check that bpf_map_delete/update_elem() was called from timer
 	 * callback_fn. In such case we don't call hrtimer_cancel() (since it
 	 * will deadlock) and don't call hrtimer_try_to_cancel() (since it will
 	 * just return -1). Though callback_fn is still running on this cpu it's
@@ -1636,6 +1630,21 @@ void bpf_timer_cancel_and_free(void *val)
 	}
 }
 
+/*
+ * This function is called by map_delete/update_elem for individual element and
+ * by ops->map_release_uref when the user space reference to a map reaches zero.
+ */
+void bpf_timer_cancel_and_free(void *val)
+{
+	struct bpf_hrtimer *t;
+
+	t = (struct bpf_hrtimer *)__bpf_async_cancel_and_free(val);
+	if (!t)
+		return;
+
+	bpf_timer_delete(t);
+}
+
 /* This function is called by map_delete/update_elem for individual element and
  * by ops->map_release_uref when the user space reference to a map reaches zero.
  */

-- 
2.51.1

  parent reply	other threads:[~2025-10-31 21:59 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-31 21:58 [PATCH RFC 0/5] bpf: avoid locks in bpf_timer and bpf_wq Mykyta Yatsenko
2025-10-31 21:58 ` [PATCH RFC v1 1/5] bpf: refactor bpf_async_cb callback update Mykyta Yatsenko
2025-11-04  1:58   ` Eduard Zingerman
2025-10-31 21:58 ` [PATCH RFC v1 2/5] bpf: refactor bpf_async_cb prog swap Mykyta Yatsenko
2025-11-04 18:42   ` Eduard Zingerman
2025-10-31 21:58 ` Mykyta Yatsenko [this message]
2025-11-04 18:45   ` [PATCH RFC v1 3/5] bpf: factor out timer deletion helper Eduard Zingerman
2025-10-31 21:58 ` [PATCH RFC v1 4/5] bpf: add refcnt into struct bpf_async_cb Mykyta Yatsenko
2025-10-31 22:35   ` bot+bpf-ci
2025-11-03 18:14     ` Alexei Starovoitov
2025-10-31 21:58 ` [PATCH RFC v1 5/5] bpf: remove lock from bpf_async_cb Mykyta Yatsenko
2025-11-04 22:01   ` Eduard Zingerman
2025-11-05 15:30     ` Mykyta Yatsenko
2025-11-05 22:44       ` Eduard Zingerman
2025-11-05 23:39         ` Mykyta Yatsenko
2025-11-06  0:08           ` Eduard Zingerman

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