Patch "xprtrdma: Don't defer fencing an async RPC's chunks" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    xprtrdma: Don't defer fencing an async RPC's chunks

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xprtrdma-don-t-defer-fencing-an-async-rpc-s-chunks.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Dec 18 13:29:00 CET 2017
From: Chuck Lever <chuck.lever@oracle.com>
Date: Mon, 9 Oct 2017 12:03:26 -0400
Subject: xprtrdma: Don't defer fencing an async RPC's chunks

From: Chuck Lever <chuck.lever@oracle.com>


[ Upstream commit 8f66b1a529047a972cb9602a919c53a95f3d7a2b ]

In current kernels, waiting in xprt_release appears to be safe to
do. I had erroneously believed that for ASYNC RPCs, waiting of any
kind in xprt_release->xprt_rdma_free would result in deadlock. I've
done injection testing and consulted with Trond to confirm that
waiting in the RPC release path is safe.

For the very few times where RPC resources haven't yet been released
earlier by the reply handler, it is safe to wait synchronously in
xprt_rdma_free for invalidation rather than defering it to MR
recovery.

Note: When the QP is error state, posting a LocalInvalidate should
flush and mark the MR as bad. There is no way the remote HCA can
access that MR via a QP in error state, so it is effectively already
inaccessible and thus safe for the Upper Layer to access. The next
time the MR is used it should be recognized and cleaned up properly
by frwr_op_map.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sunrpc/xprtrdma/transport.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -686,7 +686,7 @@ xprt_rdma_free(struct rpc_task *task)
 	dprintk("RPC:       %s: called on 0x%p\n", __func__, req->rl_reply);
 
 	if (!list_empty(&req->rl_registered))
-		ia->ri_ops->ro_unmap_safe(r_xprt, req, !RPC_IS_ASYNC(task));
+		ia->ri_ops->ro_unmap_sync(r_xprt, &req->rl_registered);
 	rpcrdma_unmap_sges(ia, req);
 	rpcrdma_buffer_put(req);
 }


Patches currently in stable-queue which might be from chuck.lever@oracle.com are

queue-4.14/xprtrdma-don-t-defer-fencing-an-async-rpc-s-chunks.patch
queue-4.14/sunrpc-fix-a-race-in-the-receive-code-path.patch