From 16b304f3404f8e0243d5ee2b70b68767b7b59b2b Mon Sep 17 00:00:00 2001 From: Pravin B Shelar Date: Thu, 15 Aug 2013 15:31:06 -0700 Subject: [PATCH] netlink: Eliminate kmalloc in netlink dump operation. Following patch stores struct netlink_callback in netlink_sock to avoid allocating and freeing it on every netlink dump msg. Only one dump operation is allowed for a given socket at a time therefore we can safely convert cb pointer to cb struct inside netlink_sock. Signed-off-by: Pravin B Shelar Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 97 +++++++++++++++++++++--------------------------- net/netlink/af_netlink.h | 3 +- 2 files changed, 44 insertions(+), 56 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 6273772..a17dda1 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -595,7 +595,7 @@ static unsigned int netlink_poll(struct file *file, struct socket *sock, * for dumps is performed here. A dump is allowed to continue * if at least half the ring is unused. */ - while (nlk->cb != NULL && netlink_dump_space(nlk)) { + while (nlk->cb_running && netlink_dump_space(nlk)) { err = netlink_dump(sk); if (err < 0) { sk->sk_err = err; @@ -802,18 +802,6 @@ static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb) #define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0 #endif /* CONFIG_NETLINK_MMAP */ -static void netlink_destroy_callback(struct netlink_callback *cb) -{ - kfree_skb(cb->skb); - kfree(cb); -} - -static void netlink_consume_callback(struct netlink_callback *cb) -{ - consume_skb(cb->skb); - kfree(cb); -} - static void netlink_skb_destructor(struct sk_buff *skb) { #ifdef CONFIG_NETLINK_MMAP @@ -872,12 +860,12 @@ static void netlink_sock_destruct(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); - if (nlk->cb) { - if (nlk->cb->done) - nlk->cb->done(nlk->cb); + if (nlk->cb_running) { + if (nlk->cb.done) + nlk->cb.done(&nlk->cb); - module_put(nlk->cb->module); - netlink_destroy_callback(nlk->cb); + module_put(nlk->cb.module); + kfree_skb(nlk->cb.skb); } skb_queue_purge(&sk->sk_receive_queue); @@ -2350,7 +2338,8 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, skb_free_datagram(sk, skb); - if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { + if (nlk->cb_running && + atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { ret = netlink_dump(sk); if (ret) { sk->sk_err = ret; @@ -2566,13 +2555,12 @@ static int netlink_dump(struct sock *sk) int alloc_size; mutex_lock(nlk->cb_mutex); - - cb = nlk->cb; - if (cb == NULL) { + if (!nlk->cb_running) { err = -EINVAL; goto errout_skb; } + cb = &nlk->cb; alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); if (!netlink_rx_is_mmaped(sk) && @@ -2610,11 +2598,11 @@ static int netlink_dump(struct sock *sk) if (cb->done) cb->done(cb); - nlk->cb = NULL; - mutex_unlock(nlk->cb_mutex); + nlk->cb_running = false; + mutex_unlock(nlk->cb_mutex); module_put(cb->module); - netlink_consume_callback(cb); + consume_skb(cb->skb); return 0; errout_skb: @@ -2632,59 +2620,51 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, struct netlink_sock *nlk; int ret; - cb = kzalloc(sizeof(*cb), GFP_KERNEL); - if (cb == NULL) - return -ENOBUFS; - /* Memory mapped dump requests need to be copied to avoid looping * on the pending state in netlink_mmap_sendmsg() while the CB hold * a reference to the skb. */ if (netlink_skb_is_mmaped(skb)) { skb = skb_copy(skb, GFP_KERNEL); - if (skb == NULL) { - kfree(cb); + if (skb == NULL) return -ENOBUFS; - } } else atomic_inc(&skb->users); - cb->dump = control->dump; - cb->done = control->done; - cb->nlh = nlh; - cb->data = control->data; - cb->module = control->module; - cb->min_dump_alloc = control->min_dump_alloc; - cb->skb = skb; - sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); if (sk == NULL) { - netlink_destroy_callback(cb); - return -ECONNREFUSED; + ret = -ECONNREFUSED; + goto error_free; } - nlk = nlk_sk(sk); + nlk = nlk_sk(sk); mutex_lock(nlk->cb_mutex); /* A dump is in progress... */ - if (nlk->cb) { - mutex_unlock(nlk->cb_mutex); - netlink_destroy_callback(cb); + if (nlk->cb_running) { ret = -EBUSY; - goto out; + goto error_unlock; } /* add reference of module which cb->dump belongs to */ - if (!try_module_get(cb->module)) { - mutex_unlock(nlk->cb_mutex); - netlink_destroy_callback(cb); + if (!try_module_get(control->module)) { ret = -EPROTONOSUPPORT; - goto out; + goto error_unlock; } - nlk->cb = cb; + cb = &nlk->cb; + memset(cb, 0, sizeof(*cb)); + cb->dump = control->dump; + cb->done = control->done; + cb->nlh = nlh; + cb->data = control->data; + cb->module = control->module; + cb->min_dump_alloc = control->min_dump_alloc; + cb->skb = skb; + + nlk->cb_running = true; + mutex_unlock(nlk->cb_mutex); ret = netlink_dump(sk); -out: sock_put(sk); if (ret) @@ -2694,6 +2674,13 @@ out: * signal not to send ACK even if it was requested. */ return -EINTR; + +error_unlock: + sock_put(sk); + mutex_unlock(nlk->cb_mutex); +error_free: + kfree_skb(skb); + return ret; } EXPORT_SYMBOL(__netlink_dump_start); @@ -2916,14 +2903,14 @@ static int netlink_seq_show(struct seq_file *seq, void *v) struct sock *s = v; struct netlink_sock *nlk = nlk_sk(s); - seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %pK %-8d %-8d %-8lu\n", + seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n", s, s->sk_protocol, nlk->portid, nlk->groups ? (u32)nlk->groups[0] : 0, sk_rmem_alloc_get(s), sk_wmem_alloc_get(s), - nlk->cb, + nlk->cb_running, atomic_read(&s->sk_refcnt), atomic_read(&s->sk_drops), sock_i_ino(s) diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h index eaa88d1..acbd774 100644 --- a/net/netlink/af_netlink.h +++ b/net/netlink/af_netlink.h @@ -32,7 +32,8 @@ struct netlink_sock { unsigned long *groups; unsigned long state; wait_queue_head_t wait; - struct netlink_callback *cb; + bool cb_running; + struct netlink_callback cb; struct mutex *cb_mutex; struct mutex cb_def_mutex; void (*netlink_rcv)(struct sk_buff *skb); -- 2.7.4