io_uring/zcrx: protect netdev with pp_lock

Remove ifq->lock and reuse pp_lock to protect the netdev pointer.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: isilence

io_uring/zcrx.c

@@ -476,20 +476,19 @@ static struct io_zcrx_ifq *io_zcrx_ifq_alloc(struct io_ring_ctx *ctx)
 
 	ifq->if_rxq = -1;
 	ifq->ctx = ctx;
-	spin_lock_init(&ifq->lock);
 	spin_lock_init(&ifq->rq_lock);
 	mutex_init(&ifq->pp_lock);
 	return ifq;
 }
 
 static void io_zcrx_drop_netdev(struct io_zcrx_ifq *ifq)
 {
-	spin_lock(&ifq->lock);
-	if (ifq->netdev) {
-		netdev_put(ifq->netdev, &ifq->netdev_tracker);
-		ifq->netdev = NULL;
-	}
-	spin_unlock(&ifq->lock);
+	guard(mutex)(&ifq->pp_lock);
+
+	if (!ifq->netdev)
+		return;
+	netdev_put(ifq->netdev, &ifq->netdev_tracker);
+	ifq->netdev = NULL;
 }
 
 static void io_close_queue(struct io_zcrx_ifq *ifq)
@@ -504,11 +503,11 @@ static void io_close_queue(struct io_zcrx_ifq *ifq)
 	if (ifq->if_rxq == -1)
 		return;
 
-	spin_lock(&ifq->lock);
-	netdev = ifq->netdev;
-	netdev_tracker = ifq->netdev_tracker;
-	ifq->netdev = NULL;
-	spin_unlock(&ifq->lock);
+	scoped_guard(mutex, &ifq->pp_lock) {
+		netdev = ifq->netdev;
+		netdev_tracker = ifq->netdev_tracker;
+		ifq->netdev = NULL;
+	}
 
 	if (netdev) {
 		net_mp_close_rxq(netdev, ifq->if_rxq, &p);

io_uring/zcrx.h

@@ -53,7 +53,6 @@ struct io_zcrx_ifq {
 	struct device			*dev;
 	struct net_device		*netdev;
 	netdevice_tracker		netdev_tracker;
-	spinlock_t			lock;
 
 	/*
 	 * Page pool and net configuration lock, can be taken deeper in the