[PATCH net-next 2/8] net: designate XSK pool pointers in queues as "ops protected"

Jakub Kicinski
2025-04-07T19:01:19Z

Read accesses go via xsk_get_pool_from_qid(), the call coming
from the core and gve look safe (other "ops locked" drivers
don't support XSK).

Write accesses go via xsk_reg_pool_at_qid() and xsk_clear_pool_at_qid().
Former is already under the ops lock, latter needs to be locked when
coming from the workqueue via xp_clear_dev().

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
include/linux/netdevice.h | 1 +
include/net/netdev_rx_queue.h | 6 +++---
net/xdp/xsk.c | 2 ++
net/xdp/xsk_buff_pool.c | 7 ++++++-
4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8e9be80bc167..7242fb8a22fc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -688,6 +688,7 @@ struct netdev_queue {
/* Subordinate device that the queue has been assigned to */
struct net_device *sb_dev;
#ifdef CONFIG_XDP_SOCKETS
+ /* "ops protected", see comment about net_device::lock */
struct xsk_buff_pool *pool;
#endif

diff --git a/include/net/netdev_rx_queue.h b/include/net/netdev_rx_queue.h
index b2238b551dce..8cdcd138b33f 100644
--- a/include/net/netdev_rx_queue.h
+++ b/include/net/netdev_rx_queue.h
@@ -20,12 +20,12 @@ struct netdev_rx_queue {
struct net_device *dev;
netdevice_tracker dev_tracker;

+ /* All fields below are "ops protected",
+ * see comment about net_device::lock
+ */
#ifdef CONFIG_XDP_SOCKETS
struct xsk_buff_pool *pool;
#endif
- /* NAPI instance for the queue
- * "ops protected", see comment about net_device::lock
- */
struct napi_struct *napi;
struct pp_memory_provider_params mp_params;
} ____cacheline_aligned_in_smp;
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 5696af45bcf7..2ecf063a2c38 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -1654,7 +1654,9 @@ static int xsk_notifier(struct notifier_block *this,
xsk_unbind_dev(xs);

/* Clear device references. */
+ netdev_lock_ops(dev);
xp_clear_dev(xs->pool);
+ netdev_unlock_ops(dev);
}
mutex_unlock(&xs->mutex);
}
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 25a76c5ce0f1..c7e50fd86c6a 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -279,9 +279,14 @@ static void xp_release_deferred(struct work_struct *work)
{
struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool,
work);
+ struct net_device *netdev = pool->netdev;

rtnl_lock();
- xp_clear_dev(pool);
+ if (netdev) {
+ netdev_lock_ops(netdev);
+ xp_clear_dev(pool);
+ netdev_unlock_ops(netdev);
+ }
rtnl_unlock();

if (pool->fq) {
--
2.49.0