From def3117493eafd9dfa1f809d861e0031b2cc8a07 Mon Sep 17 00:00:00 2001 From: Pravin B Shelar Date: Tue, 23 Apr 2013 07:48:30 +0000 Subject: [PATCH] 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: Pravin B Shelar Signed-off-by: David S. Miller --- include/net/genetlink.h | 1 + net/netlink/genetlink.c | 114 ++++++++++++++++++++++++++-------------- 2 files changed, 77 insertions(+), 38 deletions(-) diff --git a/include/net/genetlink.h b/include/net/genetlink.h index bdfbe68c1c3..93024a47e0e 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -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); diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 5a55be3f17a..2f72598dd8f 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -16,10 +16,12 @@ #include #include #include +#include #include #include 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 == ¬ify_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) { + struct netlink_dump_control c = { + .dump = ops->dumpit, + .done = ops->done, + }; + 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; + 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 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(); + + err = genl_family_rcv_msg(family, skb, nlh); + + if (!family->parallel_ops) + genl_unlock(); + return err; } static void genl_rcv(struct sk_buff *skb) { - genl_lock(); + down_read(&cb_lock); netlink_rcv_skb(skb, &genl_rcv_msg); - genl_unlock(); + 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, }; -- 2.43.2