[PATCH 4.1 072/159] SUNRPC: Lock the transport layer on shutdown

Greg Kroah-Hartman
2015-09-26T21:08:35Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

commit 79234c3db6842a3de03817211d891e0c2878f756 upstream.

Avoid all races with the connect/disconnect handlers by taking the
transport lock.

Reported-by:"Suzuki K. Poulose" <suzuki.poulose@arm.com>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/sunrpc/xprt.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -611,6 +611,7 @@ static void xprt_autoclose(struct work_s
xprt->ops->close(xprt);
clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
xprt_release_write(xprt, NULL);
+ wake_up_bit(&xprt->state, XPRT_LOCKED);
}

/**
@@ -720,6 +721,7 @@ void xprt_unlock_connect(struct rpc_xprt
xprt->ops->release_xprt(xprt, NULL);
out:
spin_unlock_bh(&xprt->transport_lock);
+ wake_up_bit(&xprt->state, XPRT_LOCKED);
}

/**
@@ -1389,6 +1391,10 @@ out:
static void xprt_destroy(struct rpc_xprt *xprt)
{
dprintk("RPC: destroying transport %p\n", xprt);
+
+ /* Exclude transport connect/disconnect handlers */
+ wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_UNINTERRUPTIBLE);
+
del_timer_sync(&xprt->timer);

rpc_xprt_debugfs_unregister(xprt);