Use a dedicated mutex instead. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima --- v2: addressed Jakub feedback v1: https://lore.kernel.org/netdev/20250627130839.4082270-1-edumazet@google.com/ net/core/net-sysfs.c | 15 ++++++++++++--- net/core/net-sysfs.h | 2 ++ net/core/sysctl_net_core.c | 37 ++++++++++++++----------------------- 3 files changed, 28 insertions(+), 26 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index c9b96938639999ddc1fe52560e0ba2c4f1adff1f..8f897e2c8b4fe125a941f869709458830310169d 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1210,12 +1210,21 @@ static int rx_queue_default_mask(struct net_device *dev, struct netdev_rx_queue *queue) { #if IS_ENABLED(CONFIG_RPS) && IS_ENABLED(CONFIG_SYSCTL) - struct cpumask *rps_default_mask = READ_ONCE(dev_net(dev)->core.rps_default_mask); + struct cpumask *rps_default_mask; + int res = 0; + mutex_lock(&rps_default_mask_mutex); + + rps_default_mask = dev_net(dev)->core.rps_default_mask; if (rps_default_mask && !cpumask_empty(rps_default_mask)) - return netdev_rx_queue_set_rps_mask(queue, rps_default_mask); -#endif + res = netdev_rx_queue_set_rps_mask(queue, rps_default_mask); + + mutex_unlock(&rps_default_mask_mutex); + + return res; +#else return 0; +#endif } static int rx_queue_add_kobject(struct net_device *dev, int index) diff --git a/net/core/net-sysfs.h b/net/core/net-sysfs.h index 8a5b04c2699aaee13ccc3a5b1543eecd0fc10d29..e938f25e8e86f9dfd8f710a08922c4cabf662c2e 100644 --- a/net/core/net-sysfs.h +++ b/net/core/net-sysfs.h @@ -11,4 +11,6 @@ int netdev_queue_update_kobjects(struct net_device *net, int netdev_change_owner(struct net_device *, const struct net *net_old, const struct net *net_new); +extern struct mutex rps_default_mask_mutex; + #endif diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 5dbb2c6f371defbf79d4581f9b6c1c3fb13fa9d9..8cf04b57ade1e0bf61ad4ac219ab4eccf638658a 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -28,6 +28,7 @@ #include #include "dev.h" +#include "net-sysfs.h" static int int_3600 = 3600; static int min_sndbuf = SOCK_MIN_SNDBUF; @@ -96,50 +97,40 @@ static int dump_cpumask(void *buffer, size_t *lenp, loff_t *ppos, #ifdef CONFIG_RPS -static struct cpumask *rps_default_mask_cow_alloc(struct net *net) -{ - struct cpumask *rps_default_mask; - - if (net->core.rps_default_mask) - return net->core.rps_default_mask; - - rps_default_mask = kzalloc(cpumask_size(), GFP_KERNEL); - if (!rps_default_mask) - return NULL; - - /* pairs with READ_ONCE in rx_queue_default_mask() */ - WRITE_ONCE(net->core.rps_default_mask, rps_default_mask); - return rps_default_mask; -} +DEFINE_MUTEX(rps_default_mask_mutex); static int rps_default_mask_sysctl(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { struct net *net = (struct net *)table->data; + struct cpumask *mask; int err = 0; - rtnl_lock(); + mutex_lock(&rps_default_mask_mutex); + mask = net->core.rps_default_mask; if (write) { - struct cpumask *rps_default_mask = rps_default_mask_cow_alloc(net); - + if (!mask) { + mask = kzalloc(cpumask_size(), GFP_KERNEL); + net->core.rps_default_mask = mask; + } err = -ENOMEM; - if (!rps_default_mask) + if (!mask) goto done; - err = cpumask_parse(buffer, rps_default_mask); + err = cpumask_parse(buffer, mask); if (err) goto done; - err = rps_cpumask_housekeeping(rps_default_mask); + err = rps_cpumask_housekeeping(mask); if (err) goto done; } else { err = dump_cpumask(buffer, lenp, ppos, - net->core.rps_default_mask ? : cpu_none_mask); + mask ?: cpu_none_mask); } done: - rtnl_unlock(); + mutex_unlock(&rps_default_mask_mutex); return err; } -- 2.50.0.727.gbf7dc18ff4-goog