Re: [PATCH v2] SUNRPC: Initialize rpc_rqst outside of xprt->reserve_lock

[Anna Schumaker <Anna.Schumaker@Netapp.com>]

Hi Chuck,

On 03/11/2018 11:27 AM, Chuck Lever wrote:
> alloc_slot is a transport-specific op, but initializing an rpc_rqst
> is common to all transports. In addition, the only part of initial-
> izing an rpc_rqst that needs serialization is getting a fresh XID.
> 
> Move rpc_rqst initialization to common code in preparation for
> adding a transport-specific alloc_slot to xprtrdma.

I'm having trouble with this patch again.  This time I'm running xfstests generic/074 with NFS v4.0, and my client starts seeing "nfs: server 192.168.100.215 not responding, still trying" after about a minute.  Any thoughts about what's going on here?  I keep trying to capture it with Wireshark, but there are enough packets on the wire to crash Wireshark.

Thoughts?
Anna

> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  include/linux/sunrpc/xprt.h |    1 +
>  net/sunrpc/clnt.c           |    1 +
>  net/sunrpc/xprt.c           |   12 +++++++-----
>  3 files changed, 9 insertions(+), 5 deletions(-)
> 
> Changes since v1:
> - Partial sends should not bump the XID
> 
> diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
> index 5fea0fb..9784e28 100644
> --- a/include/linux/sunrpc/xprt.h
> +++ b/include/linux/sunrpc/xprt.h
> @@ -324,6 +324,7 @@ struct xprt_class {
>  struct rpc_xprt		*xprt_create_transport(struct xprt_create *args);
>  void			xprt_connect(struct rpc_task *task);
>  void			xprt_reserve(struct rpc_task *task);
> +void			xprt_request_init(struct rpc_task *task);
>  void			xprt_retry_reserve(struct rpc_task *task);
>  int			xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
>  int			xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index 6e432ec..226f558 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -1546,6 +1546,7 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
>  	task->tk_status = 0;
>  	if (status >= 0) {
>  		if (task->tk_rqstp) {
> +			xprt_request_init(task);
>  			task->tk_action = call_refresh;
>  			return;
>  		}
> diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
> index 70f0050..2d95926 100644
> --- a/net/sunrpc/xprt.c
> +++ b/net/sunrpc/xprt.c
> @@ -66,7 +66,7 @@
>   * Local functions
>   */
>  static void	 xprt_init(struct rpc_xprt *xprt, struct net *net);
> -static void	xprt_request_init(struct rpc_task *, struct rpc_xprt *);
> +static __be32	xprt_alloc_xid(struct rpc_xprt *xprt);
>  static void	xprt_connect_status(struct rpc_task *task);
>  static int      __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
>  static void     __xprt_put_cong(struct rpc_xprt *, struct rpc_rqst *);
> @@ -987,6 +987,8 @@ bool xprt_prepare_transmit(struct rpc_task *task)
>  		task->tk_status = -EAGAIN;
>  		goto out_unlock;
>  	}
> +	if (!bc_prealloc(req) && !req->rq_xmit_bytes_sent)
> +		req->rq_xid = xprt_alloc_xid(xprt);
>  	ret = true;
>  out_unlock:
>  	spin_unlock_bh(&xprt->transport_lock);
> @@ -1163,10 +1165,10 @@ void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
>  out_init_req:
>  	xprt->stat.max_slots = max_t(unsigned int, xprt->stat.max_slots,
>  				     xprt->num_reqs);
> +	spin_unlock(&xprt->reserve_lock);
> +
>  	task->tk_status = 0;
>  	task->tk_rqstp = req;
> -	xprt_request_init(task, xprt);
> -	spin_unlock(&xprt->reserve_lock);
>  }
>  EXPORT_SYMBOL_GPL(xprt_alloc_slot);
>  
> @@ -1303,8 +1305,9 @@ static inline void xprt_init_xid(struct rpc_xprt *xprt)
>  	xprt->xid = prandom_u32();
>  }
>  
> -static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
> +void xprt_request_init(struct rpc_task *task)
>  {
> +	struct rpc_xprt *xprt = task->tk_xprt;
>  	struct rpc_rqst	*req = task->tk_rqstp;
>  
>  	INIT_LIST_HEAD(&req->rq_list);
> @@ -1312,7 +1315,6 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
>  	req->rq_task	= task;
>  	req->rq_xprt    = xprt;
>  	req->rq_buffer  = NULL;
> -	req->rq_xid     = xprt_alloc_xid(xprt);
>  	req->rq_connect_cookie = xprt->connect_cookie - 1;
>  	req->rq_bytes_sent = 0;
>  	req->rq_snd_buf.len = 0;
>