[PATCH 3.16 154/306] ipv4: use the right lock for ping_group_range

[Ben Hutchings]

3.16.40-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: WANG Cong <xiyou.wangcong@xxxxxxxxx>

commit 396a30cce15d084b2b1a395aa6d515c3d559c674 upstream.

This reverts commit a681574c99be23e4d20b769bf0e543239c364af5
("ipv4: disable BH in set_ping_group_range()") because we never
read ping_group_range in BH context (unlike local_port_range).

Then, since we already have a lock for ping_group_range, those
using ip_local_ports.lock for ping_group_range are clearly typos.

We might consider to share a same lock for both ping_group_range
and local_port_range w.r.t. space saving, but that should be for
net-next.

Fixes: a681574c99be ("ipv4: disable BH in set_ping_group_range()")
Fixes: ba6b918ab234 ("ping: move ping_group_range out of CONFIG_SYSCTL")
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Eric Salo <salo@xxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: we never applied "ipv4: disable BH in
  set_ping_group_range()"]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/ipv4/sysctl_net_ipv4.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -90,11 +90,11 @@ static void inet_get_ping_group_range_ta
 		container_of(table->data, struct net, ipv4.ping_group_range.range);
 	unsigned int seq;
 	do {
-		seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
+		seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 
 		*low = data[0];
 		*high = data[1];
-	} while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
+	} while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 }
 
 /* Update system visible IP port range */
@@ -103,10 +103,10 @@ static void set_ping_group_range(struct
 	kgid_t *data = table->data;
 	struct net *net =
 		container_of(table->data, struct net, ipv4.ping_group_range.range);
-	write_seqlock(&net->ipv4.ip_local_ports.lock);
+	write_seqlock(&net->ipv4.ping_group_range.lock);
 	data[0] = low;
 	data[1] = high;
-	write_sequnlock(&net->ipv4.ip_local_ports.lock);
+	write_sequnlock(&net->ipv4.ping_group_range.lock);
 }
 
 /* Validate changes from /proc interface. */