Return-Path: Received: from mx142.netapp.com ([216.240.21.19]:35352 "EHLO mx142.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753173AbbLPNsj (ORCPT ); Wed, 16 Dec 2015 08:48:39 -0500 Subject: Re: [PATCH v3 09/11] SUNRPC: Introduce xprt_commit_rqst() To: Chuck Lever References: <20151214211317.16295.70115.stgit@manet.1015granger.net> <20151214211915.16295.30339.stgit@manet.1015granger.net> CC: , From: Anna Schumaker Message-ID: <56716BB4.8080500@Netapp.com> Date: Wed, 16 Dec 2015 08:48:36 -0500 MIME-Version: 1.0 In-Reply-To: <20151214211915.16295.30339.stgit@manet.1015granger.net> Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi Chuck, Sorry for the last minute comment. On 12/14/2015 04:19 PM, Chuck Lever wrote: > I'm about to add code in the RPC/RDMA reply handler between the > xprt_lookup_rqst() and xprt_complete_rqst() call site that needs > to execute outside of spinlock critical sections. > > Add a hook to remove an rpc_rqst from the pending list once > the transport knows its going to invoke xprt_complete_rqst(). > > Signed-off-by: Chuck Lever > --- > include/linux/sunrpc/xprt.h | 1 + > net/sunrpc/xprt.c | 14 ++++++++++++++ > net/sunrpc/xprtrdma/rpc_rdma.c | 4 ++++ > 3 files changed, 19 insertions(+) > > diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h > index 69ef5b3..ab6c3a5 100644 > --- a/include/linux/sunrpc/xprt.h > +++ b/include/linux/sunrpc/xprt.h > @@ -366,6 +366,7 @@ void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action); > void xprt_write_space(struct rpc_xprt *xprt); > void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result); > struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid); > +void xprt_commit_rqst(struct rpc_task *task); > void xprt_complete_rqst(struct rpc_task *task, int copied); > void xprt_release_rqst_cong(struct rpc_task *task); > void xprt_disconnect_done(struct rpc_xprt *xprt); > diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c > index 2e98f4a..a5be4ab 100644 > --- a/net/sunrpc/xprt.c > +++ b/net/sunrpc/xprt.c > @@ -837,6 +837,20 @@ static void xprt_update_rtt(struct rpc_task *task) > } > > /** > + * xprt_commit_rqst - remove rqst from pending list early > + * @task: RPC request to remove > + * > + * Caller holds transport lock. > + */ > +void xprt_commit_rqst(struct rpc_task *task) > +{ > + struct rpc_rqst *req = task->tk_rqstp; > + > + list_del_init(&req->rq_list); > +} > +EXPORT_SYMBOL_GPL(xprt_commit_rqst); Can you move this function into the xprtrdma code, since it's not called outside of there? Thanks, Anna > + > +/** > * xprt_complete_rqst - called when reply processing is complete > * @task: RPC request that recently completed > * @copied: actual number of bytes received from the transport > diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c > index c10d969..0bc8c39 100644 > --- a/net/sunrpc/xprtrdma/rpc_rdma.c > +++ b/net/sunrpc/xprtrdma/rpc_rdma.c > @@ -804,6 +804,9 @@ rpcrdma_reply_handler(struct rpcrdma_rep *rep) > if (req->rl_reply) > goto out_duplicate; > > + xprt_commit_rqst(rqst->rq_task); > + spin_unlock_bh(&xprt->transport_lock); > + > dprintk("RPC: %s: reply 0x%p completes request 0x%p\n" > " RPC request 0x%p xid 0x%08x\n", > __func__, rep, req, rqst, > @@ -894,6 +897,7 @@ badheader: > else if (credits > r_xprt->rx_buf.rb_max_requests) > credits = r_xprt->rx_buf.rb_max_requests; > > + spin_lock_bh(&xprt->transport_lock); > cwnd = xprt->cwnd; > xprt->cwnd = credits << RPC_CWNDSHIFT; > if (xprt->cwnd > cwnd) >