rds: don't let RDS shutdown a connection while senders are present
This is the first in a long line of patches that tries to fix races
between RDS connection shutdown and RDS traffic.
Here we are maintaining a count of active senders to make sure
the connection doesn't go away while they are using it.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/net/rds/send.c b/net/rds/send.c
index 8e3fd99..d35c43f 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -60,15 +60,23 @@
struct rds_message *rm, *tmp;
unsigned long flags;
+ spin_lock_irqsave(&conn->c_send_lock, flags);
if (conn->c_xmit_rm) {
+ rm = conn->c_xmit_rm;
+ conn->c_xmit_rm = NULL;
/* Tell the user the RDMA op is no longer mapped by the
* transport. This isn't entirely true (it's flushed out
* independently) but as the connection is down, there's
* no ongoing RDMA to/from that memory */
- rds_message_unmapped(conn->c_xmit_rm);
- rds_message_put(conn->c_xmit_rm);
- conn->c_xmit_rm = NULL;
+printk(KERN_CRIT "send reset unmapping %p\n", rm);
+ rds_message_unmapped(rm);
+ spin_unlock_irqrestore(&conn->c_send_lock, flags);
+
+ rds_message_put(rm);
+ } else {
+ spin_unlock_irqrestore(&conn->c_send_lock, flags);
}
+
conn->c_xmit_sg = 0;
conn->c_xmit_hdr_off = 0;
conn->c_xmit_data_off = 0;
@@ -131,6 +139,7 @@
ret = -ENOMEM;
goto out;
}
+ atomic_inc(&conn->c_senders);
if (conn->c_trans->xmit_prepare)
conn->c_trans->xmit_prepare(conn);
@@ -350,6 +359,8 @@
rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
}
+ atomic_dec(&conn->c_senders);
+
/*
* Other senders will see we have c_send_lock and exit. We
* need to recheck the send queue and race again for c_send_lock