Commit 6058099d authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: remove RTNL use for /proc/sys/net/core/rps_default_mask 



Use a dedicated mutex instead.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250702061558.1585870-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d8bf56a0

net/core/net-sysfs.c

+12 −3
Original line number Diff line number Diff line
@@ -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)

net/core/net-sysfs.h

+2 −0
Original line number Diff line number Diff line
@@ -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

net/core/sysctl_net_core.c

+14 −23
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <net/rps.h>



#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;

}