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authorSowmini Varadhan <sowmini.varadhan@oracle.com>2017-03-04 08:57:33 -0800
committerDavid S. Miller <davem@davemloft.net>2017-03-07 14:09:59 -0800
commit8edc3affc0770886c7bfb3436b0fdd09bce13167 (patch)
treecfe3a2ae7348961f4c8872ffd5158d2ba4e35235
parentfa4c7fb2ad2ea5dae57eb875915d0efb1e068543 (diff)
downloadlinux-8edc3affc0770886c7bfb3436b0fdd09bce13167.tar.bz2
rds: tcp: Take explicit refcounts on struct net
It is incorrect for the rds_connection to piggyback on the sock_net() refcount for the netns because this gives rise to a chicken-and-egg problem during rds_conn_destroy. Instead explicitly take a ref on the net, and hold the netns down till the connection tear-down is complete. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/rds/connection.c1
-rw-r--r--net/rds/rds.h6
-rw-r--r--net/rds/tcp.c4
3 files changed, 6 insertions, 5 deletions
diff --git a/net/rds/connection.c b/net/rds/connection.c
index 0e04dcceb1d4..1fa75ab7b733 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -429,6 +429,7 @@ void rds_conn_destroy(struct rds_connection *conn)
*/
rds_cong_remove_conn(conn);
+ put_net(conn->c_net);
kmem_cache_free(rds_conn_slab, conn);
spin_lock_irqsave(&rds_conn_lock, flags);
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 39518ef7af4d..82d38ccf5e8b 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -147,7 +147,7 @@ struct rds_connection {
/* Protocol version */
unsigned int c_version;
- possible_net_t c_net;
+ struct net *c_net;
struct list_head c_map_item;
unsigned long c_map_queued;
@@ -162,13 +162,13 @@ struct rds_connection {
static inline
struct net *rds_conn_net(struct rds_connection *conn)
{
- return read_pnet(&conn->c_net);
+ return conn->c_net;
}
static inline
void rds_conn_net_set(struct rds_connection *conn, struct net *net)
{
- write_pnet(&conn->c_net, net);
+ conn->c_net = get_net(net);
}
#define RDS_FLAG_CONG_BITMAP 0x01
diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index a973d3b4dff0..65c8e3b3b710 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -529,7 +529,7 @@ static void rds_tcp_kill_sock(struct net *net)
flush_work(&rtn->rds_tcp_accept_w);
spin_lock_irq(&rds_tcp_conn_lock);
list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
- struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
+ struct net *c_net = tc->t_cpath->cp_conn->c_net;
if (net != c_net || !tc->t_sock)
continue;
@@ -584,7 +584,7 @@ static void rds_tcp_sysctl_reset(struct net *net)
spin_lock_irq(&rds_tcp_conn_lock);
list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
- struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
+ struct net *c_net = tc->t_cpath->cp_conn->c_net;
if (net != c_net || !tc->t_sock)
continue;