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 --- net/sunrpc/xprtrdma/transport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index c84e2b644e13..8cf5ccfe180d 100644 --- 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); }