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RDS: Rewrite connection cleanup, fixing oops on rmmod

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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>
This commit is contained in:
Andy Grover
2009-04-01 08:20:19 +00:00
committed by David S. Miller
parent f1cffcbfcc
commit 745cbccac3
8 changed files with 119 additions and 95 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/rds/ib_cm.c
+19 -15
View File
@@ -126,9 +126,7 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even
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 @@ void rds_ib_conn_shutdown(struct rds_connection *conn)
/*
* 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 @@ int rds_ib_conn_alloc(struct rds_connection *conn, gfp_t gfp)
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);
}