[RFC net-next 08/15] xsk: Handle a detached FILL ring in RX wakeup
flat view
From: Björn Töpel <bjorn@kernel.org>
Date: 2026-10-02 19:01:36
Also in:
bpf, io-uring, linux-doc, lkml
Subsystem:
networking [general], the rest, xdp sockets (af_xdp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski
A buffer pool used as a memory provider can live longer than its FILL ring, while an old page pool finishes a deferred destroy. The RX need-wakeup helpers use pool->fq without a NULL check. Read pool->fq once and return if it is NULL. A normal pool always has a FILL ring here, so nothing changes for it. Signed-off-by: Björn Töpel <bjorn@kernel.org> --- net/xdp/xsk.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 33475b180ea6..b68dda9c37d1 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c@@ -50,10 +50,15 @@ static struct kmem_cache *xsk_tx_generic_cache; void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool) { + struct xsk_queue *fq = READ_ONCE(pool->fq); + + if (!fq) + return; + if (pool->cached_need_wakeup & XDP_WAKEUP_RX) return; - pool->fq->ring->flags |= XDP_RING_NEED_WAKEUP; + fq->ring->flags |= XDP_RING_NEED_WAKEUP; pool->cached_need_wakeup |= XDP_WAKEUP_RX; } EXPORT_SYMBOL(xsk_set_rx_need_wakeup);
@@ -77,10 +82,15 @@ EXPORT_SYMBOL(xsk_set_tx_need_wakeup); void xsk_clear_rx_need_wakeup(struct xsk_buff_pool *pool) { + struct xsk_queue *fq = READ_ONCE(pool->fq); + + if (!fq) + return; + if (!(pool->cached_need_wakeup & XDP_WAKEUP_RX)) return; - pool->fq->ring->flags &= ~XDP_RING_NEED_WAKEUP; + fq->ring->flags &= ~XDP_RING_NEED_WAKEUP; pool->cached_need_wakeup &= ~XDP_WAKEUP_RX; } EXPORT_SYMBOL(xsk_clear_rx_need_wakeup);
--
2.55.0