From nobody Tue Dec 2 02:06:44 2025 Received: from unimail.uni-dortmund.de (mx1.hrz.uni-dortmund.de [129.217.128.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD82436C0BF; Thu, 20 Nov 2025 15:30:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=129.217.128.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763652612; cv=none; b=OlmOAd+H021XsmuwzM/OQYvrndE8lexieojrEWxMUSIvTCa4Vns4BVMbVSBMIfkjaA4Cg5grod+XtrQ8UQnj0UXFtAXmC+uIQGjlhBUtstzKQOrC/nA5KGimo9d+Ymu+hYKj3si1OXv3gtKF/sq2o0wkxdq+qF32MICK0BMsJGs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763652612; c=relaxed/simple; bh=6DGyWUwfWBo3+7vPw1G3Yayb2lMMOQLoHAP+Dn91EbI=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MbN/FXoOKZILXqekMGwenBN1YhWTtRqCW762G7vaZwtoILZkdloLHZq9HAU0yGcaq/DPLNxpdXmGTTHhlK20lt7UdSiNf6JMETdP5zJVnfPavpeNiiKEBoN1oKdJAD753KSMlnjibXfdPonYl7g1vS87G7NiU1K4sXD1SJSYqNE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=tu-dortmund.de; spf=pass smtp.mailfrom=tu-dortmund.de; arc=none smtp.client-ip=129.217.128.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=tu-dortmund.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tu-dortmund.de Received: from simon-Latitude-5450.cni.e-technik.tu-dortmund.de ([129.217.186.248]) (authenticated bits=0) by unimail.uni-dortmund.de (8.18.1.10/8.18.1.10) with ESMTPSA id 5AKFTu8G005406 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 20 Nov 2025 16:29:58 +0100 (CET) From: Simon Schippers To: willemdebruijn.kernel@gmail.com, jasowang@redhat.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, mst@redhat.com, eperezma@redhat.com, jon@nutanix.com, tim.gebauer@tu-dortmund.de, simon.schippers@tu-dortmund.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux.dev Subject: [PATCH net-next v6 5/8] tun/tap: add uncomsume function for returning entries to ring Date: Thu, 20 Nov 2025 16:29:10 +0100 Message-ID: <20251120152914.1127975-6-simon.schippers@tu-dortmund.de> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251120152914.1127975-1-simon.schippers@tu-dortmund.de> References: <20251120152914.1127975-1-simon.schippers@tu-dortmund.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add tun_ring_unconsume() and tap_ring_unconsume() wrappers to allow external modules (e.g. vhost-net) to return previously consumed entries back to the ring. This complements tun_ring_consume_batched() and tap_ring_consume_batched() and enables proper error handling when consumed packets need to be rolled back. The functions delegate to ptr_ring_unconsume() and take a destroy callback for entries that cannot be returned to the ring. Co-developed-by: Tim Gebauer Signed-off-by: Tim Gebauer Co-developed by: Jon Kohler Signed-off-by: Jon Kohler Signed-off-by: Simon Schippers --- drivers/net/tap.c | 10 ++++++++++ drivers/net/tun.c | 10 ++++++++++ include/linux/if_tap.h | 4 ++++ include/linux/if_tun.h | 5 +++++ 4 files changed, 29 insertions(+) diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 01717c8fd284..0069e2f177f4 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -837,6 +837,16 @@ int tap_ring_consume_batched(struct file *file, void *= *array, int n) } EXPORT_SYMBOL_GPL(tap_ring_consume_batched); =20 +void tap_ring_unconsume(struct file *file, void **batch, int n, + void (*destroy)(void *)) +{ + struct tap_queue *q =3D file->private_data; + struct ptr_ring *ring =3D &q->ring; + + ptr_ring_unconsume(ring, batch, n, destroy); +} +EXPORT_SYMBOL_GPL(tap_ring_unconsume); + static ssize_t tap_do_read(struct tap_queue *q, struct iov_iter *to, int noblock, struct sk_buff *skb) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 42df185341ad..bf109440d2c7 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -3837,6 +3837,16 @@ int tun_ring_consume_batched(struct file *file, void= **array, int n) } EXPORT_SYMBOL_GPL(tun_ring_consume_batched); =20 +void tun_ring_unconsume(struct file *file, void **batch, int n, + void (*destroy)(void *)) +{ + struct tun_file *tfile =3D file->private_data; + struct ptr_ring *ring =3D &tfile->tx_ring; + + ptr_ring_unconsume(ring, batch, n, destroy); +} +EXPORT_SYMBOL_GPL(tun_ring_unconsume); + struct ptr_ring *tun_get_tx_ring(struct file *file) { struct tun_file *tfile; diff --git a/include/linux/if_tap.h b/include/linux/if_tap.h index cf8b90320b8d..28326a69745a 100644 --- a/include/linux/if_tap.h +++ b/include/linux/if_tap.h @@ -12,6 +12,8 @@ struct socket; struct socket *tap_get_socket(struct file *); struct ptr_ring *tap_get_ptr_ring(struct file *file); int tap_ring_consume_batched(struct file *file, void **array, int n); +void tap_ring_unconsume(struct file *file, void **batch, int n, + void (*destroy)(void *)); #else #include #include @@ -28,6 +30,8 @@ static inline int tap_ring_consume_batched(struct file *f, { return 0; } +static inline void tap_ring_unconsume(struct file *file, void **batch, + int n, void (*destroy)(void *)) {} #endif /* CONFIG_TAP */ =20 /* diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h index 444dda75a372..1274c6b34eb6 100644 --- a/include/linux/if_tun.h +++ b/include/linux/if_tun.h @@ -23,6 +23,8 @@ struct tun_msg_ctl { struct socket *tun_get_socket(struct file *); struct ptr_ring *tun_get_tx_ring(struct file *file); int tun_ring_consume_batched(struct file *file, void **array, int n); +void tun_ring_unconsume(struct file *file, void **batch, int n, + void (*destroy)(void *)); =20 static inline bool tun_is_xdp_frame(void *ptr) { @@ -62,6 +64,9 @@ static inline int tun_ring_consume_batched(struct file *f= ile, return 0; } =20 +static inline void tun_ring_unconsume(struct file *file, void **batch, + int n, void (*destroy)(void *)) {} + static inline bool tun_is_xdp_frame(void *ptr) { return false; --=20 2.43.0