Merge branch 'rds-next'
Sowmini Varadhan says:
====================
net/rds: SOL_RDS socket option to explicitly select transport
Today the underlying transport (TCP or IB) for a PF_RDS socket is
implicitly selected based on the local address used to bind(2) the
PF_RDS socket. This results in some non-deterministic behavior when
there are un-numbered and IPoIB interfaces sharing the same IP address.
It also places the constraint that the IB interface must have an IP
address (and thus, IPoIB) configured on it.
The non-determinism may be avoided by providing the user-space application
a socket option that allows it to explicitly select the transport
prior to bind(2).
Patch 1 of this series provides the constant definitions needed by
the application via <linux/rds.h>.
Patch 2 provides the setsockopt support, and Patch 3 provides the
getsockopt support.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/rds.h b/include/uapi/linux/rds.h
index 9195095..0f9265c 100644
--- a/include/uapi/linux/rds.h
+++ b/include/uapi/linux/rds.h
@@ -38,6 +38,8 @@
#define RDS_IB_ABI_VERSION 0x301
+#define SOL_RDS 276
+
/*
* setsockopt/getsockopt for SOL_RDS
*/
@@ -48,6 +50,14 @@
#define RDS_RECVERR 5
#define RDS_CONG_MONITOR 6
#define RDS_GET_MR_FOR_DEST 7
+#define SO_RDS_TRANSPORT 8
+
+/* supported values for SO_RDS_TRANSPORT */
+#define RDS_TRANS_IB 0
+#define RDS_TRANS_IWARP 1
+#define RDS_TRANS_TCP 2
+#define RDS_TRANS_COUNT 3
+#define RDS_TRANS_NONE (~0)
/*
* Control message types for SOL_RDS.
diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c
index 3d83641..2ad9032 100644
--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c
@@ -270,6 +270,28 @@
return ret;
}
+static int rds_set_transport(struct rds_sock *rs, char __user *optval,
+ int optlen)
+{
+ int t_type;
+
+ if (rs->rs_transport)
+ return -EOPNOTSUPP; /* previously attached to transport */
+
+ if (optlen != sizeof(int))
+ return -EINVAL;
+
+ if (copy_from_user(&t_type, (int __user *)optval, sizeof(t_type)))
+ return -EFAULT;
+
+ if (t_type < 0 || t_type >= RDS_TRANS_COUNT)
+ return -EINVAL;
+
+ rs->rs_transport = rds_trans_get(t_type);
+
+ return rs->rs_transport ? 0 : -ENOPROTOOPT;
+}
+
static int rds_setsockopt(struct socket *sock, int level, int optname,
char __user *optval, unsigned int optlen)
{
@@ -300,6 +322,11 @@
case RDS_CONG_MONITOR:
ret = rds_cong_monitor(rs, optval, optlen);
break;
+ case SO_RDS_TRANSPORT:
+ lock_sock(sock->sk);
+ ret = rds_set_transport(rs, optval, optlen);
+ release_sock(sock->sk);
+ break;
default:
ret = -ENOPROTOOPT;
}
@@ -312,6 +339,7 @@
{
struct rds_sock *rs = rds_sk_to_rs(sock->sk);
int ret = -ENOPROTOOPT, len;
+ int trans;
if (level != SOL_RDS)
goto out;
@@ -337,6 +365,19 @@
else
ret = 0;
break;
+ case SO_RDS_TRANSPORT:
+ if (len < sizeof(int)) {
+ ret = -EINVAL;
+ break;
+ }
+ trans = (rs->rs_transport ? rs->rs_transport->t_type :
+ RDS_TRANS_NONE); /* unbound */
+ if (put_user(trans, (int __user *)optval) ||
+ put_user(sizeof(int), optlen))
+ ret = -EFAULT;
+ else
+ ret = 0;
+ break;
default:
break;
}
diff --git a/net/rds/bind.c b/net/rds/bind.c
index a2e6562..4ebd29c 100644
--- a/net/rds/bind.c
+++ b/net/rds/bind.c
@@ -181,6 +181,10 @@
if (ret)
goto out;
+ if (rs->rs_transport) { /* previously bound */
+ ret = 0;
+ goto out;
+ }
trans = rds_trans_get_preferred(sin->sin_addr.s_addr);
if (!trans) {
ret = -EADDRNOTAVAIL;
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 0d41155..a33fb4a 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -408,11 +408,6 @@
* should try hard not to block.
*/
-#define RDS_TRANS_IB 0
-#define RDS_TRANS_IWARP 1
-#define RDS_TRANS_TCP 2
-#define RDS_TRANS_COUNT 3
-
struct rds_transport {
char t_name[TRANSNAMSIZ];
struct list_head t_item;
@@ -803,6 +798,7 @@
void rds_trans_put(struct rds_transport *trans);
unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
unsigned int avail);
+struct rds_transport *rds_trans_get(int t_type);
int rds_trans_init(void);
void rds_trans_exit(void);
diff --git a/net/rds/transport.c b/net/rds/transport.c
index 7f2ac4f..8b4a6cd 100644
--- a/net/rds/transport.c
+++ b/net/rds/transport.c
@@ -101,6 +101,27 @@
return ret;
}
+struct rds_transport *rds_trans_get(int t_type)
+{
+ struct rds_transport *ret = NULL;
+ struct rds_transport *trans;
+ unsigned int i;
+
+ down_read(&rds_trans_sem);
+ for (i = 0; i < RDS_TRANS_COUNT; i++) {
+ trans = transports[i];
+
+ if (trans && trans->t_type == t_type &&
+ (!trans->t_owner || try_module_get(trans->t_owner))) {
+ ret = trans;
+ break;
+ }
+ }
+ up_read(&rds_trans_sem);
+
+ return ret;
+}
+
/*
* This returns the number of stats entries in the snapshot and only
* copies them using the iter if there is enough space for them. The