[PATCH net-next 09/11] net: designate XSK pool pointers in queues as "ops protected"

[Jakub Kicinski <kuba@kernel.org>]

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().

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/linux/netdevice.h     | 1 +
 include/net/netdev_rx_queue.h | 6 +++---
 net/xdp/xsk_buff_pool.c       | 3 +++
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0fc79ae60ff5..7d802ef1c864 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_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 14716ad3d7bc..60b3adb7b2d7 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -279,9 +279,12 @@ 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();
+	netdev_lock_ops(netdev);
 	xp_clear_dev(pool);
+	netdev_unlock_ops(netdev);
 	rtnl_unlock();
 
 	if (pool->fq) {
-- 
2.48.1