Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit def31174 authored by Pravin B Shelar's avatar Pravin B Shelar Committed by David S. Miller
Browse files

genl: Allow concurrent genl callbacks. 



All genl callbacks are serialized by genl-mutex. This can become
bottleneck in multi threaded case.
Following patch adds an parameter to genl_family so that a
particular family can get concurrent netlink callback without
genl_lock held.
New rw-sem is used to protect genl callback from genl family unregister.
in case of parallel_ops genl-family read-lock is taken for callbacks and
write lock is taken for register or unregistration for any family.
In case of locked genl family semaphore and gel-mutex is locked for
any openration.

Signed-off-by: default avatarPravin B Shelar <pshelar@nicira.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 133b9424

include/net/genetlink.h

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ struct genl_family { 
	unsigned int		version;

	unsigned int		maxattr;

	bool			netnsok;

	bool			parallel_ops;

	int			(*pre_doit)(struct genl_ops *ops,

					    struct sk_buff *skb,

					    struct genl_info *info);

net/netlink/genetlink.c

+76 −38
Original line number Diff line number Diff line
@@ -16,10 +16,12 @@ 
#include <linux/skbuff.h>

#include <linux/mutex.h>

#include <linux/bitmap.h>

#include <linux/rwsem.h>

#include <net/sock.h>

#include <net/genetlink.h>



static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */

static DECLARE_RWSEM(cb_lock);



void genl_lock(void)

{
@@ -41,6 +43,18 @@ int lockdep_genl_is_held(void) 
EXPORT_SYMBOL(lockdep_genl_is_held);

#endif



static void genl_lock_all(void)

{

	down_write(&cb_lock);

	genl_lock();

}



static void genl_unlock_all(void)

{

	genl_unlock();

	up_write(&cb_lock);

}



#define GENL_FAM_TAB_SIZE	16

#define GENL_FAM_TAB_MASK	(GENL_FAM_TAB_SIZE - 1)
@@ -144,7 +158,7 @@ int genl_register_mc_group(struct genl_family *family, 
	BUG_ON(grp->name[0] == '\0');

	BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);



	genl_lock();

	genl_lock_all();



	/* special-case our own group */

	if (grp == &notify_grp)
@@ -213,7 +227,7 @@ int genl_register_mc_group(struct genl_family *family, 


	genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);

 out:

	genl_unlock();

	genl_unlock_all();

	return err;

}

EXPORT_SYMBOL(genl_register_mc_group);
@@ -255,9 +269,9 @@ static void __genl_unregister_mc_group(struct genl_family *family, 
void genl_unregister_mc_group(struct genl_family *family,

			      struct genl_multicast_group *grp)

{

	genl_lock();

	genl_lock_all();

	__genl_unregister_mc_group(family, grp);

	genl_unlock();

	genl_unlock_all();

}

EXPORT_SYMBOL(genl_unregister_mc_group);
@@ -303,9 +317,9 @@ int genl_register_ops(struct genl_family *family, struct genl_ops *ops) 
	if (ops->policy)

		ops->flags |= GENL_CMD_CAP_HASPOL;



	genl_lock();

	genl_lock_all();

	list_add_tail(&ops->ops_list, &family->ops_list);

	genl_unlock();

	genl_unlock_all();



	genl_ctrl_event(CTRL_CMD_NEWOPS, ops);

	err = 0;
@@ -334,16 +348,16 @@ int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) 
{

	struct genl_ops *rc;



	genl_lock();

	genl_lock_all();

	list_for_each_entry(rc, &family->ops_list, ops_list) {

		if (rc == ops) {

			list_del(&ops->ops_list);

			genl_unlock();

			genl_unlock_all();

			genl_ctrl_event(CTRL_CMD_DELOPS, ops);

			return 0;

		}

	}

	genl_unlock();

	genl_unlock_all();



	return -ENOENT;

}
@@ -373,7 +387,7 @@ int genl_register_family(struct genl_family *family) 
	INIT_LIST_HEAD(&family->ops_list);

	INIT_LIST_HEAD(&family->mcast_groups);



	genl_lock();

	genl_lock_all();



	if (genl_family_find_byname(family->name)) {

		err = -EEXIST;
@@ -394,7 +408,7 @@ int genl_register_family(struct genl_family *family) 
		goto errout_locked;

	}



	if (family->maxattr) {

	if (family->maxattr && !family->parallel_ops) {

		family->attrbuf = kmalloc((family->maxattr+1) *

					sizeof(struct nlattr *), GFP_KERNEL);

		if (family->attrbuf == NULL) {
@@ -405,14 +419,14 @@ int genl_register_family(struct genl_family *family) 
		family->attrbuf = NULL;



	list_add_tail(&family->family_list, genl_family_chain(family->id));

	genl_unlock();

	genl_unlock_all();



	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);



	return 0;



errout_locked:

	genl_unlock();

	genl_unlock_all();

errout:

	return err;

}
@@ -476,7 +490,7 @@ int genl_unregister_family(struct genl_family *family) 
{

	struct genl_family *rc;



	genl_lock();

	genl_lock_all();



	genl_unregister_mc_groups(family);
@@ -486,14 +500,14 @@ int genl_unregister_family(struct genl_family *family) 


		list_del(&rc->family_list);

		INIT_LIST_HEAD(&family->ops_list);

		genl_unlock();

		genl_unlock_all();



		kfree(family->attrbuf);

		genl_ctrl_event(CTRL_CMD_DELFAMILY, family);

		return 0;

	}



	genl_unlock();

	genl_unlock_all();



	return -ENOENT;

}
@@ -530,19 +544,17 @@ void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 
}

EXPORT_SYMBOL(genlmsg_put);



static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)

static int genl_family_rcv_msg(struct genl_family *family,

			       struct sk_buff *skb,

			       struct nlmsghdr *nlh)

{

	struct genl_ops *ops;

	struct genl_family *family;

	struct net *net = sock_net(skb->sk);

	struct genl_info info;

	struct genlmsghdr *hdr = nlmsg_data(nlh);

	struct nlattr **attrbuf;

	int hdrlen, err;



	family = genl_family_find_byid(nlh->nlmsg_type);

	if (family == NULL)

		return -ENOENT;



	/* this family doesn't exist in this netns */

	if (!family->netnsok && !net_eq(net, &init_net))

		return -ENOENT;
@@ -560,26 +572,30 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
		return -EPERM;



	if (nlh->nlmsg_flags & NLM_F_DUMP) {

		if (ops->dumpit == NULL)

			return -EOPNOTSUPP;



		genl_unlock();

		{

		struct netlink_dump_control c = {

			.dump = ops->dumpit,

			.done = ops->done,

		};

			err = netlink_dump_start(net->genl_sock, skb, nlh, &c);

		}

		genl_lock();

		return err;



		if (ops->dumpit == NULL)

			return -EOPNOTSUPP;



		return netlink_dump_start(net->genl_sock, skb, nlh, &c);

	}



	if (ops->doit == NULL)

		return -EOPNOTSUPP;



	if (family->attrbuf) {

		err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,

	if (family->maxattr && family->parallel_ops) {

		attrbuf = kmalloc((family->maxattr+1) *

					sizeof(struct nlattr *), GFP_KERNEL);

		if (attrbuf == NULL)

			return -ENOMEM;

	} else

		attrbuf = family->attrbuf;



	if (attrbuf) {

		err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,

				  ops->policy);

		if (err < 0)

			return err;
@@ -590,7 +606,7 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
	info.nlhdr = nlh;

	info.genlhdr = nlmsg_data(nlh);

	info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;

	info.attrs = family->attrbuf;

	info.attrs = attrbuf;

	genl_info_net_set(&info, net);

	memset(&info.user_ptr, 0, sizeof(info.user_ptr));
@@ -605,14 +621,37 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
	if (family->post_doit)

		family->post_doit(ops, skb, &info);



	if (family->parallel_ops)

		kfree(attrbuf);



	return err;

}



static void genl_rcv(struct sk_buff *skb)

static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)

{

	struct genl_family *family;

	int err;



	family = genl_family_find_byid(nlh->nlmsg_type);

	if (family == NULL)

		return -ENOENT;



	if (!family->parallel_ops)

		genl_lock();

	netlink_rcv_skb(skb, &genl_rcv_msg);



	err = genl_family_rcv_msg(family, skb, nlh);



	if (!family->parallel_ops)

		genl_unlock();



	return err;

}



static void genl_rcv(struct sk_buff *skb)

{

	down_read(&cb_lock);

	netlink_rcv_skb(skb, &genl_rcv_msg);

	up_read(&cb_lock);

}



/**************************************************************************
@@ -918,7 +957,6 @@ static int __net_init genl_pernet_init(struct net *net) 
{

	struct netlink_kernel_cfg cfg = {

		.input		= genl_rcv,

		.cb_mutex	= &genl_mutex,

		.flags		= NL_CFG_F_NONROOT_RECV,

	};