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%3Ba=su...

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