From 5756d346c7cdefcd84a8ac4901167cdfb5447b69 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Jun 2010 15:47:41 +0200 Subject: [PATCH] netfilter: ip_queue: rwlock to spinlock conversion Converts queue_lock rwlock to a spinlock. (readlocked part can be changed by reads of integer values) One atomic operation instead of four per ipq_enqueue_packet() call. Signed-off-by: Eric Dumazet Signed-off-by: Patrick McHardy --- net/ipv4/netfilter/ip_queue.c | 57 +++++++++++++++-------------------- 1 file changed, 25 insertions(+), 32 deletions(-) diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c index a4e5fc5df4bf..d2c1311cb28d 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -42,7 +42,7 @@ typedef int (*ipq_cmpfn)(struct nf_queue_entry *, unsigned long); static unsigned char copy_mode __read_mostly = IPQ_COPY_NONE; static unsigned int queue_maxlen __read_mostly = IPQ_QMAX_DEFAULT; -static DEFINE_RWLOCK(queue_lock); +static DEFINE_SPINLOCK(queue_lock); static int peer_pid __read_mostly; static unsigned int copy_range __read_mostly; static unsigned int queue_total; @@ -72,10 +72,10 @@ __ipq_set_mode(unsigned char mode, unsigned int range) break; case IPQ_COPY_PACKET: - copy_mode = mode; + if (range > 0xFFFF) + range = 0xFFFF; copy_range = range; - if (copy_range > 0xFFFF) - copy_range = 0xFFFF; + copy_mode = mode; break; default: @@ -101,7 +101,7 @@ ipq_find_dequeue_entry(unsigned long id) { struct nf_queue_entry *entry = NULL, *i; - write_lock_bh(&queue_lock); + spin_lock_bh(&queue_lock); list_for_each_entry(i, &queue_list, list) { if ((unsigned long)i == id) { @@ -115,7 +115,7 @@ ipq_find_dequeue_entry(unsigned long id) queue_total--; } - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); return entry; } @@ -136,9 +136,9 @@ __ipq_flush(ipq_cmpfn cmpfn, unsigned long data) static void ipq_flush(ipq_cmpfn cmpfn, unsigned long data) { - write_lock_bh(&queue_lock); + spin_lock_bh(&queue_lock); __ipq_flush(cmpfn, data); - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); } static struct sk_buff * @@ -152,9 +152,7 @@ ipq_build_packet_message(struct nf_queue_entry *entry, int *errp) struct nlmsghdr *nlh; struct timeval tv; - read_lock_bh(&queue_lock); - - switch (copy_mode) { + switch (ACCESS_ONCE(copy_mode)) { case IPQ_COPY_META: case IPQ_COPY_NONE: size = NLMSG_SPACE(sizeof(*pmsg)); @@ -162,26 +160,21 @@ ipq_build_packet_message(struct nf_queue_entry *entry, int *errp) case IPQ_COPY_PACKET: if (entry->skb->ip_summed == CHECKSUM_PARTIAL && - (*errp = skb_checksum_help(entry->skb))) { - read_unlock_bh(&queue_lock); + (*errp = skb_checksum_help(entry->skb))) return NULL; - } - if (copy_range == 0 || copy_range > entry->skb->len) + + data_len = ACCESS_ONCE(copy_range); + if (data_len == 0 || data_len > entry->skb->len) data_len = entry->skb->len; - else - data_len = copy_range; size = NLMSG_SPACE(sizeof(*pmsg) + data_len); break; default: *errp = -EINVAL; - read_unlock_bh(&queue_lock); return NULL; } - read_unlock_bh(&queue_lock); - skb = alloc_skb(size, GFP_ATOMIC); if (!skb) goto nlmsg_failure; @@ -242,7 +235,7 @@ ipq_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum) if (nskb == NULL) return status; - write_lock_bh(&queue_lock); + spin_lock_bh(&queue_lock); if (!peer_pid) goto err_out_free_nskb; @@ -266,14 +259,14 @@ ipq_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum) __ipq_enqueue_entry(entry); - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); return status; err_out_free_nskb: kfree_skb(nskb); err_out_unlock: - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); return status; } @@ -342,9 +335,9 @@ ipq_set_mode(unsigned char mode, unsigned int range) { int status; - write_lock_bh(&queue_lock); + spin_lock_bh(&queue_lock); status = __ipq_set_mode(mode, range); - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); return status; } @@ -440,11 +433,11 @@ __ipq_rcv_skb(struct sk_buff *skb) if (security_netlink_recv(skb, CAP_NET_ADMIN)) RCV_SKB_FAIL(-EPERM); - write_lock_bh(&queue_lock); + spin_lock_bh(&queue_lock); if (peer_pid) { if (peer_pid != pid) { - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); RCV_SKB_FAIL(-EBUSY); } } else { @@ -452,7 +445,7 @@ __ipq_rcv_skb(struct sk_buff *skb) peer_pid = pid; } - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); status = ipq_receive_peer(NLMSG_DATA(nlh), type, nlmsglen - NLMSG_LENGTH(0)); @@ -497,10 +490,10 @@ ipq_rcv_nl_event(struct notifier_block *this, struct netlink_notify *n = ptr; if (event == NETLINK_URELEASE && n->protocol == NETLINK_FIREWALL) { - write_lock_bh(&queue_lock); + spin_lock_bh(&queue_lock); if ((net_eq(n->net, &init_net)) && (n->pid == peer_pid)) __ipq_reset(); - write_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); } return NOTIFY_DONE; } @@ -527,7 +520,7 @@ static ctl_table ipq_table[] = { #ifdef CONFIG_PROC_FS static int ip_queue_show(struct seq_file *m, void *v) { - read_lock_bh(&queue_lock); + spin_lock_bh(&queue_lock); seq_printf(m, "Peer PID : %d\n" @@ -545,7 +538,7 @@ static int ip_queue_show(struct seq_file *m, void *v) queue_dropped, queue_user_dropped); - read_unlock_bh(&queue_lock); + spin_unlock_bh(&queue_lock); return 0; } -- 2.30.2