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Commit 2ae0f17d authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

genetlink: use idr to track families 



Since generic netlink family IDs are small integers, allocated
densely, IDR is an ideal match for lookups. Replace the existing
hand-written hash-table with IDR for allocation and lookup.

This lets the families only be written to once, during register,
since the list_head can be removed and removal of a family won't
cause any writes.

It also slightly reduces the code size (by about 1.3k on x86-64).

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 489111e5

include/net/genetlink.h

+15 −16
Original line number Diff line number Diff line
@@ -40,7 +40,6 @@ struct genl_info; 
 *	generic netlink family is removed while there are still open

 *	sockets.

 * @attrbuf: buffer to store parsed attributes (private)

 * @family_list: family list (private)

 * @mcgrps: multicast groups used by this family

 * @n_mcgrps: number of multicast groups

 * @mcgrp_offset: starting number of multicast group IDs in this family
@@ -70,11 +69,10 @@ struct genl_family { 
	unsigned int		n_ops;

	unsigned int		n_mcgrps;

	unsigned int		mcgrp_offset;	/* private */

	struct list_head	family_list;	/* private */

	struct module		*module;

};



struct nlattr **genl_family_attrbuf(struct genl_family *family);

struct nlattr **genl_family_attrbuf(const struct genl_family *family);



/**

 * struct genl_info - receiving information
@@ -134,12 +132,12 @@ struct genl_ops { 
};



int genl_register_family(struct genl_family *family);

int genl_unregister_family(struct genl_family *family);

void genl_notify(struct genl_family *family, struct sk_buff *skb,

int genl_unregister_family(const struct genl_family *family);

void genl_notify(const struct genl_family *family, struct sk_buff *skb,

		 struct genl_info *info, u32 group, gfp_t flags);



void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,

		  struct genl_family *family, int flags, u8 cmd);

		  const struct genl_family *family, int flags, u8 cmd);



/**

 * genlmsg_nlhdr - Obtain netlink header from user specified header
@@ -148,8 +146,8 @@ void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 
 *

 * Returns pointer to netlink header.

 */

static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,

					     struct genl_family *family)

static inline struct nlmsghdr *

genlmsg_nlhdr(void *user_hdr, const struct genl_family *family)

{

	return (struct nlmsghdr *)((char *)user_hdr -

				   family->hdrsize -
@@ -185,7 +183,7 @@ static inline int genlmsg_parse(const struct nlmsghdr *nlh, 
 */

static inline void genl_dump_check_consistent(struct netlink_callback *cb,

					      void *user_hdr,

					      struct genl_family *family)

					      const struct genl_family *family)

{

	nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));

}
@@ -202,7 +200,7 @@ static inline void genl_dump_check_consistent(struct netlink_callback *cb, 
 */

static inline void *genlmsg_put_reply(struct sk_buff *skb,

				      struct genl_info *info,

				      struct genl_family *family,

				      const struct genl_family *family,

				      int flags, u8 cmd)

{

	return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
@@ -239,7 +237,7 @@ static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) 
 * @group: offset of multicast group in groups array

 * @flags: allocation flags

 */

static inline int genlmsg_multicast_netns(struct genl_family *family,

static inline int genlmsg_multicast_netns(const struct genl_family *family,

					  struct net *net, struct sk_buff *skb,

					  u32 portid, unsigned int group, gfp_t flags)

{
@@ -257,7 +255,7 @@ static inline int genlmsg_multicast_netns(struct genl_family *family, 
 * @group: offset of multicast group in groups array

 * @flags: allocation flags

 */

static inline int genlmsg_multicast(struct genl_family *family,

static inline int genlmsg_multicast(const struct genl_family *family,

				    struct sk_buff *skb, u32 portid,

				    unsigned int group, gfp_t flags)

{
@@ -275,7 +273,7 @@ static inline int genlmsg_multicast(struct genl_family *family, 
 *

 * This function must hold the RTNL or rcu_read_lock().

 */

int genlmsg_multicast_allns(struct genl_family *family,

int genlmsg_multicast_allns(const struct genl_family *family,

			    struct sk_buff *skb, u32 portid,

			    unsigned int group, gfp_t flags);
@@ -359,8 +357,9 @@ static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) 
 * This function returns the number of broadcast listeners that have set the

 * NETLINK_RECV_NO_ENOBUFS socket option.

 */

static inline int genl_set_err(struct genl_family *family, struct net *net,

			       u32 portid, u32 group, int code)

static inline int genl_set_err(const struct genl_family *family,

			       struct net *net, u32 portid,

			       u32 group, int code)

{

	if (WARN_ON_ONCE(group >= family->n_mcgrps))

		return -EINVAL;
@@ -368,7 +367,7 @@ static inline int genl_set_err(struct genl_family *family, struct net *net, 
	return netlink_set_err(net->genl_sock, portid, group, code);

}



static inline int genl_has_listeners(struct genl_family *family,

static inline int genl_has_listeners(const struct genl_family *family,

				     struct net *net, unsigned int group)

{

	if (WARN_ON_ONCE(group >= family->n_mcgrps))

include/uapi/linux/genetlink.h

+2 −0
Original line number Diff line number Diff line
@@ -29,6 +29,8 @@ struct genlmsghdr { 
#define GENL_ID_CTRL		NLMSG_MIN_TYPE

#define GENL_ID_VFS_DQUOT	(NLMSG_MIN_TYPE + 1)

#define GENL_ID_PMCRAID		(NLMSG_MIN_TYPE + 2)

/* must be last reserved + 1 */

#define GENL_START_ALLOC	(NLMSG_MIN_TYPE + 3)



/**************************************************************************

 * Controller

net/netlink/genetlink.c

+106 −165
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/mutex.h>

#include <linux/bitmap.h>

#include <linux/rwsem.h>

#include <linux/idr.h>

#include <net/sock.h>

#include <net/genetlink.h>
@@ -58,10 +59,8 @@ static void genl_unlock_all(void) 
	up_write(&cb_lock);

}



#define GENL_FAM_TAB_SIZE	16

#define GENL_FAM_TAB_MASK	(GENL_FAM_TAB_SIZE - 1)

static DEFINE_IDR(genl_fam_idr);



static struct list_head family_ht[GENL_FAM_TAB_SIZE];

/*

 * Bitmap of multicast groups that are currently in use.

 *
@@ -86,45 +85,29 @@ static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | 
static unsigned long *mc_groups = &mc_group_start;

static unsigned long mc_groups_longs = 1;



static int genl_ctrl_event(int event, struct genl_family *family,

static int genl_ctrl_event(int event, const struct genl_family *family,

			   const struct genl_multicast_group *grp,

			   int grp_id);



static inline unsigned int genl_family_hash(unsigned int id)

static const struct genl_family *genl_family_find_byid(unsigned int id)

{

	return id & GENL_FAM_TAB_MASK;

	return idr_find(&genl_fam_idr, id);

}



static inline struct list_head *genl_family_chain(unsigned int id)

static const struct genl_family *genl_family_find_byname(char *name)

{

	return &family_ht[genl_family_hash(id)];

}



static struct genl_family *genl_family_find_byid(unsigned int id)

{

	struct genl_family *f;



	list_for_each_entry(f, genl_family_chain(id), family_list)

		if (f->id == id)

			return f;



	return NULL;

}

	const struct genl_family *family;

	unsigned int id;



static struct genl_family *genl_family_find_byname(char *name)

{

	struct genl_family *f;

	int i;



	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)

		list_for_each_entry(f, genl_family_chain(i), family_list)

			if (strcmp(f->name, name) == 0)

				return f;

	idr_for_each_entry(&genl_fam_idr, family, id)

		if (strcmp(family->name, name) == 0)

			return family;



	return NULL;

}



static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)

static const struct genl_ops *genl_get_cmd(u8 cmd,

					   const struct genl_family *family)

{

	int i;
@@ -135,26 +118,6 @@ static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) 
	return NULL;

}



/* Of course we are going to have problems once we hit

 * 2^16 alive types, but that can only happen by year 2K

*/

static u16 genl_generate_id(void)

{

	static u16 id_gen_idx = GENL_MIN_ID;

	int i;



	for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {

		if (id_gen_idx != GENL_ID_VFS_DQUOT &&

		    id_gen_idx != GENL_ID_PMCRAID &&

		    !genl_family_find_byid(id_gen_idx))

			return id_gen_idx;

		if (++id_gen_idx > GENL_MAX_ID)

			id_gen_idx = GENL_MIN_ID;

	}



	return 0;

}



static int genl_allocate_reserve_groups(int n_groups, int *first_id)

{

	unsigned long *new_groups;
@@ -295,7 +258,7 @@ static int genl_validate_assign_mc_groups(struct genl_family *family) 
	return err;

}



static void genl_unregister_mc_groups(struct genl_family *family)

static void genl_unregister_mc_groups(const struct genl_family *family)

{

	struct net *net;

	int i;
@@ -358,6 +321,7 @@ static int genl_validate_ops(const struct genl_family *family) 
int genl_register_family(struct genl_family *family)

{

	int err, i;

	int start = GENL_START_ALLOC, end = GENL_MAX_ID;



	err = genl_validate_ops(family);

	if (err)
@@ -370,14 +334,6 @@ int genl_register_family(struct genl_family *family) 
		goto errout_locked;

	}



	if (family == &genl_ctrl) {

		family->id = GENL_ID_CTRL;

	} else {

		u16 newid;



		/* this should be left zero in the struct */

		WARN_ON(family->id);



	/*

	 * Sadly, a few cases need to be special-cased

	 * due to them having previously abused the API
@@ -385,19 +341,13 @@ int genl_register_family(struct genl_family *family) 
	 * multicast group ID, so we use reserved IDs

	 * for both to be sure we can do that mapping.

	 */

		if (strcmp(family->name, "pmcraid") == 0)

			newid = GENL_ID_PMCRAID;

		else if (strcmp(family->name, "VFS_DQUOT") == 0)

			newid = GENL_ID_VFS_DQUOT;

		else

			newid = genl_generate_id();



		if (!newid) {

			err = -ENOMEM;

			goto errout_locked;

		}



		family->id = newid;

	if (family == &genl_ctrl) {

		/* and this needs to be special for initial family lookups */

		start = end = GENL_ID_CTRL;

	} else if (strcmp(family->name, "pmcraid") == 0) {

		start = end = GENL_ID_PMCRAID;

	} else if (strcmp(family->name, "VFS_DQUOT") == 0) {

		start = end = GENL_ID_VFS_DQUOT;

	}



	if (family->maxattr && !family->parallel_ops) {
@@ -410,11 +360,15 @@ int genl_register_family(struct genl_family *family) 
	} else

		family->attrbuf = NULL;



	family->id = idr_alloc(&genl_fam_idr, family,

			       start, end + 1, GFP_KERNEL);

	if (!family->id)

		goto errout_locked;



	err = genl_validate_assign_mc_groups(family);

	if (err)

		goto errout_locked;

		goto errout_remove;



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

	genl_unlock_all();



	/* send all events */
@@ -425,6 +379,8 @@ int genl_register_family(struct genl_family *family) 


	return 0;



errout_remove:

	idr_remove(&genl_fam_idr, family->id);

errout_locked:

	genl_unlock_all();

	return err;
@@ -439,32 +395,29 @@ EXPORT_SYMBOL(genl_register_family); 
 *

 * Returns 0 on success or a negative error code.

 */

int genl_unregister_family(struct genl_family *family)

int genl_unregister_family(const struct genl_family *family)

{

	struct genl_family *rc;



	genl_lock_all();



	list_for_each_entry(rc, genl_family_chain(family->id), family_list) {

		if (family->id != rc->id || strcmp(rc->name, family->name))

			continue;

	if (genl_family_find_byid(family->id)) {

		genl_unlock_all();

		return -ENOENT;

	}



	genl_unregister_mc_groups(family);



		list_del(&rc->family_list);

	idr_remove(&genl_fam_idr, family->id);



	up_write(&cb_lock);

	wait_event(genl_sk_destructing_waitq,

		   atomic_read(&genl_sk_destructing_cnt) == 0);

	genl_unlock();



	kfree(family->attrbuf);

		genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);

		return 0;

	}



	genl_unlock_all();

	genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);



	return -ENOENT;

	return 0;

}

EXPORT_SYMBOL(genl_unregister_family);
@@ -480,7 +433,7 @@ EXPORT_SYMBOL(genl_unregister_family); 
 * Returns pointer to user specific header

 */

void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,

				struct genl_family *family, int flags, u8 cmd)

		  const struct genl_family *family, int flags, u8 cmd)

{

	struct nlmsghdr *nlh;

	struct genlmsghdr *hdr;
@@ -539,7 +492,7 @@ static int genl_lock_done(struct netlink_callback *cb) 
	return rc;

}



static int genl_family_rcv_msg(struct genl_family *family,

static int genl_family_rcv_msg(const struct genl_family *family,

			       struct sk_buff *skb,

			       struct nlmsghdr *nlh)

{
@@ -651,7 +604,7 @@ static int genl_family_rcv_msg(struct genl_family *family, 


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

{

	struct genl_family *family;

	const struct genl_family *family;

	int err;



	family = genl_family_find_byid(nlh->nlmsg_type);
@@ -682,7 +635,7 @@ static void genl_rcv(struct sk_buff *skb) 


static struct genl_family genl_ctrl;



static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,

static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,

			  u32 flags, struct sk_buff *skb, u8 cmd)

{

	void *hdr;
@@ -769,7 +722,7 @@ static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, 
	return -EMSGSIZE;

}



static int ctrl_fill_mcgrp_info(struct genl_family *family,

static int ctrl_fill_mcgrp_info(const struct genl_family *family,

				const struct genl_multicast_group *grp,

				int grp_id, u32 portid, u32 seq, u32 flags,

				struct sk_buff *skb, u8 cmd)
@@ -812,37 +765,30 @@ static int ctrl_fill_mcgrp_info(struct genl_family *family, 


static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)

{



	int i, n = 0;

	int n = 0;

	struct genl_family *rt;

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

	int chains_to_skip = cb->args[0];

	int fams_to_skip = cb->args[1];

	int fams_to_skip = cb->args[0];

	unsigned int id;



	for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {

		n = 0;

		list_for_each_entry(rt, genl_family_chain(i), family_list) {

	idr_for_each_entry(&genl_fam_idr, rt, id) {

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

			continue;

			if (++n < fams_to_skip)



		if (n++ < fams_to_skip)

			continue;



		if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,

				   cb->nlh->nlmsg_seq, NLM_F_MULTI,

				   skb, CTRL_CMD_NEWFAMILY) < 0)

				goto errout;

		}



		fams_to_skip = 0;

			break;

	}



errout:

	cb->args[0] = i;

	cb->args[1] = n;



	cb->args[0] = n;

	return skb->len;

}



static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,

static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,

					     u32 portid, int seq, u8 cmd)

{

	struct sk_buff *skb;
@@ -862,7 +808,7 @@ static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 
}



static struct sk_buff *

ctrl_build_mcgrp_msg(struct genl_family *family,

ctrl_build_mcgrp_msg(const struct genl_family *family,

		     const struct genl_multicast_group *grp,

		     int grp_id, u32 portid, int seq, u8 cmd)

{
@@ -892,7 +838,7 @@ static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 
static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)

{

	struct sk_buff *msg;

	struct genl_family *res = NULL;

	const struct genl_family *res = NULL;

	int err = -EINVAL;



	if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
@@ -936,7 +882,7 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 
	return genlmsg_reply(msg, info);

}



static int genl_ctrl_event(int event, struct genl_family *family,

static int genl_ctrl_event(int event, const struct genl_family *family,

			   const struct genl_multicast_group *grp,

			   int grp_id)

{
@@ -1005,13 +951,13 @@ static struct genl_family genl_ctrl = { 


static int genl_bind(struct net *net, int group)

{

	int i, err = -ENOENT;

	struct genl_family *f;

	int err = -ENOENT;

	unsigned int id;



	down_read(&cb_lock);

	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {

		struct genl_family *f;



		list_for_each_entry(f, genl_family_chain(i), family_list) {

	idr_for_each_entry(&genl_fam_idr, f, id) {

		if (group >= f->mcgrp_offset &&

		    group < f->mcgrp_offset + f->n_mcgrps) {

			int fam_grp = group - f->mcgrp_offset;
@@ -1025,7 +971,6 @@ static int genl_bind(struct net *net, int group) 
			break;

		}

	}

	}

	up_read(&cb_lock);



	return err;
@@ -1033,13 +978,12 @@ static int genl_bind(struct net *net, int group) 


static void genl_unbind(struct net *net, int group)

{

	int i;

	struct genl_family *f;

	unsigned int id;



	down_read(&cb_lock);

	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {

		struct genl_family *f;



		list_for_each_entry(f, genl_family_chain(i), family_list) {

	idr_for_each_entry(&genl_fam_idr, f, id) {

		if (group >= f->mcgrp_offset &&

		    group < f->mcgrp_offset + f->n_mcgrps) {

			int fam_grp = group - f->mcgrp_offset;
@@ -1049,7 +993,6 @@ static void genl_unbind(struct net *net, int group) 
			break;

		}

	}

	}

	up_read(&cb_lock);

}
@@ -1087,10 +1030,7 @@ static struct pernet_operations genl_pernet_ops = { 


static int __init genl_init(void)

{

	int i, err;



	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)

		INIT_LIST_HEAD(&family_ht[i]);

	int err;



	err = genl_register_family(&genl_ctrl);

	if (err < 0)
@@ -1118,7 +1058,7 @@ subsys_initcall(genl_init); 
 * You cannot use this function with a family that has parallel_ops

 * and you can only use it within (pre/post) doit/dumpit callbacks.

 */

struct nlattr **genl_family_attrbuf(struct genl_family *family)

struct nlattr **genl_family_attrbuf(const struct genl_family *family)

{

	if (!WARN_ON(family->parallel_ops))

		lockdep_assert_held(&genl_mutex);
@@ -1156,8 +1096,9 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 
	return err;

}



int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,

			    u32 portid, unsigned int group, gfp_t flags)

int genlmsg_multicast_allns(const struct genl_family *family,

			    struct sk_buff *skb, u32 portid,

			    unsigned int group, gfp_t flags)

{

	if (WARN_ON_ONCE(group >= family->n_mcgrps))

		return -EINVAL;
@@ -1166,7 +1107,7 @@ int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb, 
}

EXPORT_SYMBOL(genlmsg_multicast_allns);



void genl_notify(struct genl_family *family, struct sk_buff *skb,

void genl_notify(const struct genl_family *family, struct sk_buff *skb,

		 struct genl_info *info, u32 group, gfp_t flags)

{

	struct net *net = genl_info_net(info);