An application may deterministically attach the underlying transport for
a PF_RDS socket by invoking setsockopt(2) with the SO_RDS_TRANSPORT
option at the SOL_RDS level. The integer argument to setsockopt must be
one of the RDS_TRANS_* transport types, e.g., RDS_TRANS_TCP. The option
must be specified before invoking bind(2) on the socket, and may only
be used once on the socket. An attempt to set the option on a bound
socket, or to invoke the option after a successful SO_RDS_TRANSPORT
attachment, will return EOPNOTSUPP.
Signed-off-by: Sowmini Varadhan <sowmini.varad...@oracle.com>
---
net/rds/af_rds.c | 27 +++++++++++++++++++++++++++
net/rds/bind.c | 4 ++++
net/rds/rds.h | 1 +
net/rds/transport.c | 21 +++++++++++++++++++++
4 files changed, 53 insertions(+), 0 deletions(-)
diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c
index 3d83641..0487744 100644
--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c
@@ -270,6 +270,28 @@ static int rds_cong_monitor(struct rds_sock *rs, char
__user *optval,
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 @@ static int rds_setsockopt(struct socket *sock, int level,
int optname,
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;
}
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 @@ int rds_bind(struct socket *sock, struct sockaddr *uaddr,
int addr_len)
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 76db508..a33fb4a 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -798,6 +798,7 @@ struct rds_transport *rds_trans_get_preferred(__be32 addr);
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 @@ struct rds_transport *rds_trans_get_preferred(__be32 addr)
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
--
1.7.1
--
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