[PATCH net-next v7 3/9] tun/tap: add ptr_ring consume helper with netdev queue wakeup
From: Simon Schippers <hidden>
Date: 2026-01-07 21:06:14
Also in:
kvm, lkml, virtualization
Subsystem:
networking drivers, the rest, tun/tap driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Willem de Bruijn, Jason Wang
Introduce {tun,tap}_ring_consume() helpers that wrap __ptr_ring_consume()
and wake the corresponding netdev subqueue when consuming an entry frees
space in the underlying ptr_ring.
Stopping of the netdev queue when the ptr_ring is full will be introduced
in an upcoming commit.
Co-developed-by: Tim Gebauer <redacted>
Signed-off-by: Tim Gebauer <redacted>
Signed-off-by: Simon Schippers <redacted>
---
drivers/net/tap.c | 23 ++++++++++++++++++++++-
drivers/net/tun.c | 25 +++++++++++++++++++++++--
2 files changed, 45 insertions(+), 3 deletions(-)
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 1197f245e873..2442cf7ac385 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c@@ -753,6 +753,27 @@ static ssize_t tap_put_user(struct tap_queue *q, return ret ? ret : total; } +static void *tap_ring_consume(struct tap_queue *q) +{ + struct ptr_ring *ring = &q->ring; + struct net_device *dev; + void *ptr; + + spin_lock(&ring->consumer_lock); + + ptr = __ptr_ring_consume(ring); + if (unlikely(ptr && __ptr_ring_consume_created_space(ring, 1))) { + rcu_read_lock(); + dev = rcu_dereference(q->tap)->dev; + netif_wake_subqueue(dev, q->queue_index); + rcu_read_unlock(); + } + + spin_unlock(&ring->consumer_lock); + + return ptr; +} + static ssize_t tap_do_read(struct tap_queue *q, struct iov_iter *to, int noblock, struct sk_buff *skb)
@@ -774,7 +795,7 @@ static ssize_t tap_do_read(struct tap_queue *q, TASK_INTERRUPTIBLE); /* Read frames from the queue */ - skb = ptr_ring_consume(&q->ring); + skb = tap_ring_consume(q); if (skb) break; if (noblock) {
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8192740357a0..7148f9a844a4 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c@@ -2113,13 +2113,34 @@ static ssize_t tun_put_user(struct tun_struct *tun, return total; } +static void *tun_ring_consume(struct tun_file *tfile) +{ + struct ptr_ring *ring = &tfile->tx_ring; + struct net_device *dev; + void *ptr; + + spin_lock(&ring->consumer_lock); + + ptr = __ptr_ring_consume(ring); + if (unlikely(ptr && __ptr_ring_consume_created_space(ring, 1))) { + rcu_read_lock(); + dev = rcu_dereference(tfile->tun)->dev; + netif_wake_subqueue(dev, tfile->queue_index); + rcu_read_unlock(); + } + + spin_unlock(&ring->consumer_lock); + + return ptr; +} + static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err) { DECLARE_WAITQUEUE(wait, current); void *ptr = NULL; int error = 0; - ptr = ptr_ring_consume(&tfile->tx_ring); + ptr = tun_ring_consume(tfile); if (ptr) goto out; if (noblock) {
@@ -2131,7 +2152,7 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err) while (1) { set_current_state(TASK_INTERRUPTIBLE); - ptr = ptr_ring_consume(&tfile->tx_ring); + ptr = tun_ring_consume(tfile); if (ptr) break; if (signal_pending(current)) {
--
2.43.0