RDS: Rewrite connection cleanup, fixing oops on rmmod
This fixes a bug where a connection was unexpectedly
not on *any* list while being destroyed. It also
cleans up some code duplication and regularizes some
function names.
* Grab appropriate lock in conn_free() and explain in comment
* Ensure via locking that a conn is never not on either
a dev's list or the nodev list
* Add rds_xx_remove_conn() to match rds_xx_add_conn()
* Make rds_xx_add_conn() return void
* Rename remove_{,nodev_}conns() to
destroy_{,nodev_}conns() and unify their implementation
in a helper function
* Document lock ordering as nodev conn_lock before
dev_conn_lock
Reported-by: Yosef Etigin <yosefe@voltaire.com>
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index 0532237..889ab04 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -126,9 +126,7 @@
err = rds_ib_update_ipaddr(rds_ibdev, conn->c_laddr);
if (err)
printk(KERN_ERR "rds_ib_update_ipaddr failed (%d)\n", err);
- err = rds_ib_add_conn(rds_ibdev, conn);
- if (err)
- printk(KERN_ERR "rds_ib_add_conn failed (%d)\n", err);
+ rds_ib_add_conn(rds_ibdev, conn);
/* If the peer gave us the last packet it saw, process this as if
* we had received a regular ACK. */
@@ -616,18 +614,8 @@
/*
* Move connection back to the nodev list.
*/
- if (ic->rds_ibdev) {
-
- spin_lock_irq(&ic->rds_ibdev->spinlock);
- BUG_ON(list_empty(&ic->ib_node));
- list_del(&ic->ib_node);
- spin_unlock_irq(&ic->rds_ibdev->spinlock);
-
- spin_lock_irq(&ib_nodev_conns_lock);
- list_add_tail(&ic->ib_node, &ib_nodev_conns);
- spin_unlock_irq(&ib_nodev_conns_lock);
- ic->rds_ibdev = NULL;
- }
+ if (ic->rds_ibdev)
+ rds_ib_remove_conn(ic->rds_ibdev, conn);
ic->i_cm_id = NULL;
ic->i_pd = NULL;
@@ -701,11 +689,27 @@
return 0;
}
+/*
+ * Free a connection. Connection must be shut down and not set for reconnect.
+ */
void rds_ib_conn_free(void *arg)
{
struct rds_ib_connection *ic = arg;
+ spinlock_t *lock_ptr;
+
rdsdebug("ic %p\n", ic);
+
+ /*
+ * Conn is either on a dev's list or on the nodev list.
+ * A race with shutdown() or connect() would cause problems
+ * (since rds_ibdev would change) but that should never happen.
+ */
+ lock_ptr = ic->rds_ibdev ? &ic->rds_ibdev->spinlock : &ib_nodev_conns_lock;
+
+ spin_lock_irq(lock_ptr);
list_del(&ic->ib_node);
+ spin_unlock_irq(lock_ptr);
+
kfree(ic);
}