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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: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Johannes Berg 2016-10-24 14:40:04 +02:00 committed by David S. Miller
parent 489111e5c2
commit 2ae0f17df1
3 changed files with 123 additions and 181 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
include/net/genetlink.h
View File

@ -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))

2
include/uapi/linux/genetlink.h
View File

@ -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

201
net/netlink/genetlink.c
View File

@ -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)];
}
const struct genl_family *family;
unsigned int 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;
idr_for_each_entry(&genl_fam_idr, family, id)
if (strcmp(family->name, name) == 0)
return family;
return NULL;
}
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;
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;
err = genl_validate_assign_mc_groups(family);
if (err)
family->id = idr_alloc(&genl_fam_idr, family,
start, end + 1, GFP_KERNEL);
if (!family->id)
goto errout_locked;
list_add_tail(&family->family_list, genl_family_chain(family->id));
err = genl_validate_assign_mc_groups(family);
if (err)
goto errout_remove;
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;
@ -439,33 +395,30 @@ 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();
return -ENOENT;
}
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 @@ out:
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 @@ nla_put_failure:
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 @@ nla_put_failure:
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;
break;
}
fams_to_skip = 0;
}
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);