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 <eric.dumazet@xxxxxxxxx>
---
net/ipv6/netfilter/ip6_queue.c | 57 +++++++++++++------------------
1 file changed, 25 insertions(+), 32 deletions(-)
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index 8c20174..413ab07 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -43,7 +43,7 @@ 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;
@@ -73,10 +73,10 @@ __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:
@@ -102,7 +102,7 @@ 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) {
@@ -116,7 +116,7 @@ ipq_find_dequeue_entry(unsigned long id)
queue_total--;
}
- write_unlock_bh(&queue_lock);
+ spin_unlock_bh(&queue_lock);
return entry;
}
@@ -137,9 +137,9 @@ __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 *
@@ -153,9 +153,7 @@ 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));
@@ -163,26 +161,21 @@ 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;
}
@@ -441,11 +434,11 @@ __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 {
@@ -453,7 +446,7 @@ __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));
@@ -498,10 +491,10 @@ ipq_rcv_nl_event(struct notifier_block *this,
struct netlink_notify *n = ptr;
if (event == NETLINK_URELEASE && n->protocol == NETLINK_IP6_FW) {
- 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;
}
@@ -528,7 +521,7 @@ static ctl_table ipq_table[] = {
#ifdef CONFIG_PROC_FS
static int ip6_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"
@@ -546,7 +539,7 @@ static int ip6_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;
}
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