[PATCH net-next v2 09/12] net-sysfs: remove the rtnl lock when accessing the xps maps
From: Antoine Tenart <atenart@kernel.org>
Date: 2021-02-08 17:24:11
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Now that nr_ids and num_tc are stored in the xps dev_maps, which are RCU protected, we do not have the need to protect the xps_cpus_show and xps_rxqs_show functions with the rtnl lock. Signed-off-by: Antoine Tenart <atenart@kernel.org> --- net/core/net-sysfs.c | 26 ++++---------------------- 1 file changed, 4 insertions(+), 22 deletions(-)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index c2276b589cfb..6ce5772e799e 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c@@ -1328,17 +1328,12 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, index = get_netdev_queue_index(queue); - if (!rtnl_trylock()) - return restart_syscall(); - /* If queue belongs to subordinate dev use its map */ dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev; tc = netdev_txq_to_tc(dev, index); - if (tc < 0) { - ret = -EINVAL; - goto err_rtnl_unlock; - } + if (tc < 0) + return -EINVAL; rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_maps[XPS_CPUS]);
@@ -1371,16 +1366,12 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, out_no_maps: rcu_read_unlock(); - rtnl_unlock(); - len = bitmap_print_to_pagebuf(false, buf, mask, nr_ids); bitmap_free(mask); return len < PAGE_SIZE ? len : -EINVAL; err_rcu_unlock: rcu_read_unlock(); -err_rtnl_unlock: - rtnl_unlock(); return ret; }
@@ -1435,14 +1426,9 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) index = get_netdev_queue_index(queue); - if (!rtnl_trylock()) - return restart_syscall(); - tc = netdev_txq_to_tc(dev, index); - if (tc < 0) { - ret = -EINVAL; - goto err_rtnl_unlock; - } + if (tc < 0) + return -EINVAL; rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_maps[XPS_RXQS]);
@@ -1475,8 +1461,6 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) out_no_maps: rcu_read_unlock(); - rtnl_unlock(); - len = bitmap_print_to_pagebuf(false, buf, mask, nr_ids); bitmap_free(mask);
@@ -1484,8 +1468,6 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) err_rcu_unlock: rcu_read_unlock(); -err_rtnl_unlock: - rtnl_unlock(); return ret; }
--
2.29.2