Return-Path: Received: from mail-io0-f195.google.com ([209.85.223.195]:32957 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727466AbeICWJL (ORCPT ); Mon, 3 Sep 2018 18:09:11 -0400 Received: by mail-io0-f195.google.com with SMTP id r196-v6so972798iod.0 for ; Mon, 03 Sep 2018 10:47:58 -0700 (PDT) Message-ID: <0b84ef010e4b3e4d156b6b7ac60c5fb0c2a48627.camel@gmail.com> Subject: Re: [PATCH 20/27] SUNRPC: Treat the task and request as separate in the xprt_ops->send_request() From: Trond Myklebust To: Chuck Lever Cc: Linux NFS Mailing List Date: Mon, 03 Sep 2018 13:47:56 -0400 In-Reply-To: References: <20180903152936.24325-1-trond.myklebust@hammerspace.com> <20180903152936.24325-2-trond.myklebust@hammerspace.com> <20180903152936.24325-3-trond.myklebust@hammerspace.com> <20180903152936.24325-4-trond.myklebust@hammerspace.com> <20180903152936.24325-5-trond.myklebust@hammerspace.com> <20180903152936.24325-6-trond.myklebust@hammerspace.com> <20180903152936.24325-7-trond.myklebust@hammerspace.com> <20180903152936.24325-8-trond.myklebust@hammerspace.com> <20180903152936.24325-9-trond.myklebust@hammerspace.com> <20180903152936.24325-10-trond.myklebust@hammerspace.com> <20180903152936.24325-11-trond.myklebust@hammerspace.com> <20180903152936.24325-12-trond.myklebust@hammerspace.com> <20180903152936.24325-13-trond.myklebust@hammerspace.com> <20180903152936.24325-14-trond.myklebust@hammerspace.com> <20180903152936.24325-15-trond.myklebust@hammerspace.com> <20180903152936.24325-16-trond.myklebust@hammerspace.com> <20180903152936.24325-17-trond.myklebust@hammerspace.com> <20180903152936.24325-18-trond.myklebust@hammerspace.com> <20180903152936.24325-19-trond.myklebust@hammerspace.com> <20180903152936.24325-20-trond.myklebust@hammerspace.com> <20180903152936.24325-21-trond.myklebust@hammerspace.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 2018-09-03 at 13:28 -0400, Chuck Lever wrote: > > On Sep 3, 2018, at 11:29 AM, Trond Myklebust > > wrote: > > > > When we shift to using the transmit queue, then the task that holds > > the > > write lock will not necessarily be the same as the one being > > transmitted. > > Can you pass in just the rpc_rqst? Then @task would be available as > xprt->snd_task. No. The point is that when we add queueing, @req->rq_task will usually be asleep on xprt->sending. Only the task that holds the XPRT_LOCK is awake, and so it is the one that needs to be put asleep when we hit a socket nospace/EAGAIN error. We _could_ potentially avoid passing in the task at all, and just have xs_nospace() put xprt->snd_task to sleep, but that would skirt the edge of a transport layering violation. > > > Signed-off-by: Trond Myklebust > > --- > > include/linux/sunrpc/xprt.h | 2 +- > > net/sunrpc/xprt.c | 2 +- > > net/sunrpc/xprtrdma/svc_rdma_backchannel.c | 3 +-- > > net/sunrpc/xprtrdma/transport.c | 5 ++-- > > net/sunrpc/xprtsock.c | 27 +++++++++++------ > > ----- > > 5 files changed, 18 insertions(+), 21 deletions(-) > > > > diff --git a/include/linux/sunrpc/xprt.h > > b/include/linux/sunrpc/xprt.h > > index 81a6c2c8dfc7..6d91acfe0644 100644 > > --- a/include/linux/sunrpc/xprt.h > > +++ b/include/linux/sunrpc/xprt.h > > @@ -140,7 +140,7 @@ struct rpc_xprt_ops { > > void (*connect)(struct rpc_xprt *xprt, struct > > rpc_task *task); > > int (*buf_alloc)(struct rpc_task *task); > > void (*buf_free)(struct rpc_task *task); > > - int (*send_request)(struct rpc_task *task); > > + int (*send_request)(struct rpc_rqst *req, struct > > rpc_task *task); > > void (*set_retrans_timeout)(struct rpc_task > > *task); > > void (*timer)(struct rpc_xprt *xprt, struct > > rpc_task *task); > > void (*release_request)(struct rpc_task *task); > > diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c > > index defc6167570a..3efcb69af526 100644 > > --- a/net/sunrpc/xprt.c > > +++ b/net/sunrpc/xprt.c > > @@ -1170,7 +1170,7 @@ void xprt_transmit(struct rpc_task *task) > > } > > > > connect_cookie = xprt->connect_cookie; > > - status = xprt->ops->send_request(task); > > + status = xprt->ops->send_request(req, task); > > trace_xprt_transmit(xprt, req->rq_xid, status); > > if (status != 0) { > > task->tk_status = status; > > diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c > > b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c > > index 09b12b7568fe..d1618c70edb4 100644 > > --- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c > > +++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c > > @@ -215,9 +215,8 @@ rpcrdma_bc_send_request(struct svcxprt_rdma > > *rdma, struct rpc_rqst *rqst) > > * connection. > > */ > > static int > > -xprt_rdma_bc_send_request(struct rpc_task *task) > > +xprt_rdma_bc_send_request(struct rpc_rqst *rqst, struct rpc_task > > *task) > > { > > - struct rpc_rqst *rqst = task->tk_rqstp; > > struct svc_xprt *sxprt = rqst->rq_xprt->bc_xprt; > > struct svcxprt_rdma *rdma; > > int ret; > > diff --git a/net/sunrpc/xprtrdma/transport.c > > b/net/sunrpc/xprtrdma/transport.c > > index 143ce2579ba9..fa684bf4d090 100644 > > --- a/net/sunrpc/xprtrdma/transport.c > > +++ b/net/sunrpc/xprtrdma/transport.c > > @@ -706,9 +706,8 @@ xprt_rdma_free(struct rpc_task *task) > > * sent. Do not try to send this message again. > > */ > > static int > > -xprt_rdma_send_request(struct rpc_task *task) > > +xprt_rdma_send_request(struct rpc_rqst *rqst, struct rpc_task > > *task) > > Nit: The function's documenting comment will need to be updated. > > > > { > > - struct rpc_rqst *rqst = task->tk_rqstp; > > struct rpc_xprt *xprt = rqst->rq_xprt; > > struct rpcrdma_req *req = rpcr_to_rdmar(rqst); > > struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt); > > @@ -741,7 +740,7 @@ xprt_rdma_send_request(struct rpc_task *task) > > /* An RPC with no reply will throw off credit accounting, > > * so drop the connection to reset the credit grant. > > */ > > - if (!rpc_reply_expected(task)) > > + if (!rpc_reply_expected(rqst->rq_task)) > > goto drop_connection; > > return 0; > > > > diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c > > index 8d6404259ff9..b8143eded4af 100644 > > --- a/net/sunrpc/xprtsock.c > > +++ b/net/sunrpc/xprtsock.c > > @@ -449,12 +449,12 @@ static void xs_nospace_callback(struct > > rpc_task *task) > > > > /** > > * xs_nospace - place task on wait queue if transmit was incomplete > > + * @req: pointer to RPC request > > * @task: task to put to sleep > > * > > */ > > -static int xs_nospace(struct rpc_task *task) > > +static int xs_nospace(struct rpc_rqst *req, struct rpc_task *task) > > { > > - struct rpc_rqst *req = task->tk_rqstp; > > struct rpc_xprt *xprt = req->rq_xprt; > > struct sock_xprt *transport = container_of(xprt, struct > > sock_xprt, xprt); > > struct sock *sk = transport->inet; > > @@ -513,6 +513,7 @@ static inline void > > xs_encode_stream_record_marker(struct xdr_buf *buf) > > > > /** > > * xs_local_send_request - write an RPC request to an AF_LOCAL > > socket > > + * @req: pointer to RPC request > > * @task: RPC task that manages the state of an RPC request > > * > > * Return values: > > @@ -522,9 +523,8 @@ static inline void > > xs_encode_stream_record_marker(struct xdr_buf *buf) > > * ENOTCONN: Caller needs to invoke connect logic then call > > again > > * other: Some other error occured, the request was not > > sent > > */ > > -static int xs_local_send_request(struct rpc_task *task) > > +static int xs_local_send_request(struct rpc_rqst *req, struct > > rpc_task *task) > > { > > - struct rpc_rqst *req = task->tk_rqstp; > > struct rpc_xprt *xprt = req->rq_xprt; > > struct sock_xprt *transport = > > container_of(xprt, struct sock_xprt, > > xprt); > > @@ -569,7 +569,7 @@ static int xs_local_send_request(struct > > rpc_task *task) > > case -ENOBUFS: > > break; > > case -EAGAIN: > > - status = xs_nospace(task); > > + status = xs_nospace(req, task); > > break; > > default: > > dprintk("RPC: sendmsg returned unrecognized error > > %d\n", > > @@ -585,6 +585,7 @@ static int xs_local_send_request(struct > > rpc_task *task) > > > > /** > > * xs_udp_send_request - write an RPC request to a UDP socket > > + * @req: pointer to RPC request > > * @task: address of RPC task that manages the state of an RPC > > request > > * > > * Return values: > > @@ -594,9 +595,8 @@ static int xs_local_send_request(struct > > rpc_task *task) > > * ENOTCONN: Caller needs to invoke connect logic then call > > again > > * other: Some other error occurred, the request was not > > sent > > */ > > -static int xs_udp_send_request(struct rpc_task *task) > > +static int xs_udp_send_request(struct rpc_rqst *req, struct > > rpc_task *task) > > { > > - struct rpc_rqst *req = task->tk_rqstp; > > struct rpc_xprt *xprt = req->rq_xprt; > > struct sock_xprt *transport = container_of(xprt, struct > > sock_xprt, xprt); > > struct xdr_buf *xdr = &req->rq_snd_buf; > > @@ -638,7 +638,7 @@ static int xs_udp_send_request(struct rpc_task > > *task) > > /* Should we call xs_close() here? */ > > break; > > case -EAGAIN: > > - status = xs_nospace(task); > > + status = xs_nospace(req, task); > > break; > > case -ENETUNREACH: > > case -ENOBUFS: > > @@ -658,6 +658,7 @@ static int xs_udp_send_request(struct rpc_task > > *task) > > > > /** > > * xs_tcp_send_request - write an RPC request to a TCP socket > > + * @req: pointer to RPC request > > * @task: address of RPC task that manages the state of an RPC > > request > > * > > * Return values: > > @@ -670,9 +671,8 @@ static int xs_udp_send_request(struct rpc_task > > *task) > > * XXX: In the case of soft timeouts, should we eventually give up > > * if sendmsg is not able to make progress? > > */ > > -static int xs_tcp_send_request(struct rpc_task *task) > > +static int xs_tcp_send_request(struct rpc_rqst *req, struct > > rpc_task *task) > > { > > - struct rpc_rqst *req = task->tk_rqstp; > > struct rpc_xprt *xprt = req->rq_xprt; > > struct sock_xprt *transport = container_of(xprt, struct > > sock_xprt, xprt); > > struct xdr_buf *xdr = &req->rq_snd_buf; > > @@ -697,7 +697,7 @@ static int xs_tcp_send_request(struct rpc_task > > *task) > > * completes while the socket holds a reference to the pages, > > * then we may end up resending corrupted data. > > */ > > - if (task->tk_flags & RPC_TASK_SENT) > > + if (req->rq_task->tk_flags & RPC_TASK_SENT) > > zerocopy = false; > > > > if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state)) > > @@ -761,7 +761,7 @@ static int xs_tcp_send_request(struct rpc_task > > *task) > > /* Should we call xs_close() here? */ > > break; > > case -EAGAIN: > > - status = xs_nospace(task); > > + status = xs_nospace(req, task); > > break; > > case -ECONNRESET: > > case -ECONNREFUSED: > > @@ -2706,9 +2706,8 @@ static int bc_sendto(struct rpc_rqst *req) > > /* > > * The send routine. Borrows from svc_send > > */ > > -static int bc_send_request(struct rpc_task *task) > > +static int bc_send_request(struct rpc_rqst *req, struct rpc_task > > *task) > > { > > - struct rpc_rqst *req = task->tk_rqstp; > > struct svc_xprt *xprt; > > int len; > > > > -- > > 2.17.1 > > > > -- > Chuck Lever > chucklever@gmail.com > > >