linux-kernel - [PATCH net-next v7 1/9] ptr_ring: move free-space check into separate helper

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260107210448.37851-2-simon.schippers@tu-dortmund.de>
Date: Wed,  7 Jan 2026 22:04:40 +0100
From: Simon Schippers <simon.schippers@...dortmund.de>
To: willemdebruijn.kernel@...il.com, jasowang@...hat.com,
        andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, mst@...hat.com,
        eperezma@...hat.com, leiyang@...hat.com, stephen@...workplumber.org,
        jon@...anix.com, tim.gebauer@...dortmund.de,
        simon.schippers@...dortmund.de, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux.dev
Subject: [PATCH net-next v7 1/9] ptr_ring: move free-space check into separate helper

This patch moves the check for available free space for a new entry into
a separate function. As a result, __ptr_ring_produce() remains logically
unchanged, while the new helper allows callers to determine in advance
whether subsequent __ptr_ring_produce() calls will succeed. This
information can, for example, be used to temporarily stop producing until
__ptr_ring_peek() indicates that space is available again.

Co-developed-by: Tim Gebauer <tim.gebauer@...dortmund.de>
Signed-off-by: Tim Gebauer <tim.gebauer@...dortmund.de>
Signed-off-by: Simon Schippers <simon.schippers@...dortmund.de>
---
 include/linux/ptr_ring.h | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 534531807d95..a5a3fa4916d3 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -96,6 +96,14 @@ static inline bool ptr_ring_full_bh(struct ptr_ring *r)
 	return ret;
 }
 
+static inline int __ptr_ring_produce_peek(struct ptr_ring *r)
+{
+	if (unlikely(!r->size) || r->queue[r->producer])
+		return -ENOSPC;
+
+	return 0;
+}
+
 /* Note: callers invoking this in a loop must use a compiler barrier,
  * for example cpu_relax(). Callers must hold producer_lock.
  * Callers are responsible for making sure pointer that is being queued
@@ -103,8 +111,10 @@ static inline bool ptr_ring_full_bh(struct ptr_ring *r)
  */
 static inline int __ptr_ring_produce(struct ptr_ring *r, void *ptr)
 {
-	if (unlikely(!r->size) || r->queue[r->producer])
-		return -ENOSPC;
+	int p = __ptr_ring_produce_peek(r);
+
+	if (p)
+		return p;
 
 	/* Make sure the pointer we are storing points to a valid data. */
 	/* Pairs with the dependency ordering in __ptr_ring_consume. */
-- 
2.43.0