diff mbox series

[v1,01/42] NFSD: Extract the svcxdr_init_encode() helper

Message ID 161461172449.8508.5387365342766187229.stgit@klimt.1015granger.net (mailing list archive)
State New
Headers show
Series NFSv2/3 XDR encoder overhaul | expand

Commit Message

Chuck Lever III March 1, 2021, 3:15 p.m. UTC
NFSD initializes an encode xdr_stream only after the RPC layer has
already inserted the RPC Reply header. Thus it behaves differently
than xdr_init_encode does, which assumes the passed-in xdr_buf is
entirely devoid of content.

nfs4proc.c has this server-side stream initialization helper, but
it is visible only to the NFSv4 code. Move this helper to a place
that can be accessed by NFSv2 and NFSv3 server XDR functions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs4proc.c         |   31 +++---------
 fs/nfsd/nfs4state.c        |    6 +-
 fs/nfsd/nfs4xdr.c          |  110 ++++++++++++++++++++++----------------------
 fs/nfsd/nfssvc.c           |    4 +-
 fs/nfsd/xdr4.h             |    2 -
 include/linux/sunrpc/svc.h |   25 ++++++++++
 6 files changed, 94 insertions(+), 84 deletions(-)

Comments

bfields@fieldses.org March 2, 2021, 4:47 p.m. UTC | #1
On Mon, Mar 01, 2021 at 10:15:24AM -0500, Chuck Lever wrote:
> NFSD initializes an encode xdr_stream only after the RPC layer has
> already inserted the RPC Reply header.

Out of curiosity: does it need to be this way?

--b.

> Thus it behaves differently
> than xdr_init_encode does, which assumes the passed-in xdr_buf is
> entirely devoid of content.
> 
> nfs4proc.c has this server-side stream initialization helper, but
> it is visible only to the NFSv4 code. Move this helper to a place
> that can be accessed by NFSv2 and NFSv3 server XDR functions.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  fs/nfsd/nfs4proc.c         |   31 +++---------
>  fs/nfsd/nfs4state.c        |    6 +-
>  fs/nfsd/nfs4xdr.c          |  110 ++++++++++++++++++++++----------------------
>  fs/nfsd/nfssvc.c           |    4 +-
>  fs/nfsd/xdr4.h             |    2 -
>  include/linux/sunrpc/svc.h |   25 ++++++++++
>  6 files changed, 94 insertions(+), 84 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index acdb3cd806a1..b749033e467f 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -2262,25 +2262,6 @@ static bool need_wrongsec_check(struct svc_rqst *rqstp)
>  	return !(nextd->op_flags & OP_HANDLES_WRONGSEC);
>  }
>  
> -static void svcxdr_init_encode(struct svc_rqst *rqstp,
> -			       struct nfsd4_compoundres *resp)
> -{
> -	struct xdr_stream *xdr = &resp->xdr;
> -	struct xdr_buf *buf = &rqstp->rq_res;
> -	struct kvec *head = buf->head;
> -
> -	xdr->buf = buf;
> -	xdr->iov = head;
> -	xdr->p   = head->iov_base + head->iov_len;
> -	xdr->end = head->iov_base + PAGE_SIZE - rqstp->rq_auth_slack;
> -	/* Tail and page_len should be zero at this point: */
> -	buf->len = buf->head[0].iov_len;
> -	xdr_reset_scratch_buffer(xdr);
> -	xdr->page_ptr = buf->pages - 1;
> -	buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages)
> -		- rqstp->rq_auth_slack;
> -}
> -
>  #ifdef CONFIG_NFSD_V4_2_INTER_SSC
>  static void
>  check_if_stalefh_allowed(struct nfsd4_compoundargs *args)
> @@ -2335,10 +2316,14 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
>  	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
>  	__be32		status;
>  
> -	svcxdr_init_encode(rqstp, resp);
> -	resp->tagp = resp->xdr.p;
> +	resp->xdr = &rqstp->rq_res_stream;
> +
> +	/* reserve space for: NFS status code */
> +	xdr_reserve_space(resp->xdr, XDR_UNIT);
> +
> +	resp->tagp = resp->xdr->p;
>  	/* reserve space for: taglen, tag, and opcnt */
> -	xdr_reserve_space(&resp->xdr, 8 + args->taglen);
> +	xdr_reserve_space(resp->xdr, XDR_UNIT * 2 + args->taglen);
>  	resp->taglen = args->taglen;
>  	resp->tag = args->tag;
>  	resp->rqstp = rqstp;
> @@ -2444,7 +2429,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
>  encode_op:
>  		if (op->status == nfserr_replay_me) {
>  			op->replay = &cstate->replay_owner->so_replay;
> -			nfsd4_encode_replay(&resp->xdr, op);
> +			nfsd4_encode_replay(resp->xdr, op);
>  			status = op->status = op->replay->rp_status;
>  		} else {
>  			nfsd4_encode_operation(resp, op);
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 61552e89bd89..83a498ccab19 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -2903,7 +2903,7 @@ gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, struct svc_r
>  static void
>  nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
>  {
> -	struct xdr_buf *buf = resp->xdr.buf;
> +	struct xdr_buf *buf = resp->xdr->buf;
>  	struct nfsd4_slot *slot = resp->cstate.slot;
>  	unsigned int base;
>  
> @@ -2973,7 +2973,7 @@ nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
>  			 struct nfsd4_sequence *seq)
>  {
>  	struct nfsd4_slot *slot = resp->cstate.slot;
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  	__be32 status;
>  
> @@ -3708,7 +3708,7 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>  {
>  	struct nfsd4_sequence *seq = &u->sequence;
>  	struct nfsd4_compoundres *resp = rqstp->rq_resp;
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct nfsd4_session *session;
>  	struct nfs4_client *clp;
>  	struct nfsd4_slot *slot;
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index eaaa1605b5b5..e0f06d3cbd44 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -3581,7 +3581,7 @@ nfsd4_encode_stateid(struct xdr_stream *xdr, stateid_t *sid)
>  static __be32
>  nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_access *access)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 8);
> @@ -3594,7 +3594,7 @@ nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_
>  
>  static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_bind_conn_to_session *bcts)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 8);
> @@ -3611,7 +3611,7 @@ static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp,
>  static __be32
>  nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_close *close)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	return nfsd4_encode_stateid(xdr, &close->cl_stateid);
>  }
> @@ -3620,7 +3620,7 @@ nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_c
>  static __be32
>  nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_commit *commit)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
> @@ -3634,7 +3634,7 @@ nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_
>  static __be32
>  nfsd4_encode_create(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_create *create)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 20);
> @@ -3649,7 +3649,7 @@ static __be32
>  nfsd4_encode_getattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_getattr *getattr)
>  {
>  	struct svc_fh *fhp = getattr->ga_fhp;
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	return nfsd4_encode_fattr(xdr, fhp, fhp->fh_export, fhp->fh_dentry,
>  				    getattr->ga_bmval, resp->rqstp, 0);
> @@ -3658,7 +3658,7 @@ nfsd4_encode_getattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
>  static __be32
>  nfsd4_encode_getfh(struct nfsd4_compoundres *resp, __be32 nfserr, struct svc_fh **fhpp)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct svc_fh *fhp = *fhpp;
>  	unsigned int len;
>  	__be32 *p;
> @@ -3713,7 +3713,7 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
>  static __be32
>  nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lock *lock)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	if (!nfserr)
>  		nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid);
> @@ -3726,7 +3726,7 @@ nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lo
>  static __be32
>  nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lockt *lockt)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	if (nfserr == nfserr_denied)
>  		nfsd4_encode_lock_denied(xdr, &lockt->lt_denied);
> @@ -3736,7 +3736,7 @@ nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_l
>  static __be32
>  nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_locku *locku)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	return nfsd4_encode_stateid(xdr, &locku->lu_stateid);
>  }
> @@ -3745,7 +3745,7 @@ nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_l
>  static __be32
>  nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_link *link)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 20);
> @@ -3759,7 +3759,7 @@ nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_li
>  static __be32
>  nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open *open)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	nfserr = nfsd4_encode_stateid(xdr, &open->op_stateid);
> @@ -3853,7 +3853,7 @@ nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_op
>  static __be32
>  nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_confirm *oc)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	return nfsd4_encode_stateid(xdr, &oc->oc_resp_stateid);
>  }
> @@ -3861,7 +3861,7 @@ nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct
>  static __be32
>  nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_downgrade *od)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	return nfsd4_encode_stateid(xdr, &od->od_stateid);
>  }
> @@ -3871,7 +3871,7 @@ static __be32 nfsd4_encode_splice_read(
>  				struct nfsd4_read *read,
>  				struct file *file, unsigned long maxcount)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct xdr_buf *buf = xdr->buf;
>  	int status, space_left;
>  	u32 eof;
> @@ -3937,7 +3937,7 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
>  				 struct nfsd4_read *read,
>  				 struct file *file, unsigned long maxcount)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	u32 eof;
>  	int starting_len = xdr->buf->len - 8;
>  	__be32 nfserr;
> @@ -3976,7 +3976,7 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		  struct nfsd4_read *read)
>  {
>  	unsigned long maxcount;
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct file *file;
>  	int starting_len = xdr->buf->len;
>  	__be32 *p;
> @@ -3990,7 +3990,7 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		WARN_ON_ONCE(test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags));
>  		return nfserr_resource;
>  	}
> -	if (resp->xdr.buf->page_len &&
> +	if (resp->xdr->buf->page_len &&
>  	    test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags)) {
>  		WARN_ON_ONCE(1);
>  		return nfserr_resource;
> @@ -4020,7 +4020,7 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
>  	int maxcount;
>  	__be32 wire_count;
>  	int zero = 0;
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	int length_offset = xdr->buf->len;
>  	int status;
>  	__be32 *p;
> @@ -4072,7 +4072,7 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
>  	int bytes_left;
>  	loff_t offset;
>  	__be64 wire_offset;
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	int starting_len = xdr->buf->len;
>  	__be32 *p;
>  
> @@ -4083,8 +4083,8 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
>  	/* XXX: Following NFSv3, we ignore the READDIR verifier for now. */
>  	*p++ = cpu_to_be32(0);
>  	*p++ = cpu_to_be32(0);
> -	resp->xdr.buf->head[0].iov_len = ((char *)resp->xdr.p)
> -				- (char *)resp->xdr.buf->head[0].iov_base;
> +	xdr->buf->head[0].iov_len = (char *)xdr->p -
> +				    (char *)xdr->buf->head[0].iov_base;
>  
>  	/*
>  	 * Number of bytes left for directory entries allowing for the
> @@ -4159,7 +4159,7 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
>  static __be32
>  nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_remove *remove)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 20);
> @@ -4172,7 +4172,7 @@ nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_
>  static __be32
>  nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_rename *rename)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 40);
> @@ -4255,7 +4255,7 @@ static __be32
>  nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		     struct nfsd4_secinfo *secinfo)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	return nfsd4_do_encode_secinfo(xdr, secinfo->si_exp);
>  }
> @@ -4264,7 +4264,7 @@ static __be32
>  nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		     struct nfsd4_secinfo_no_name *secinfo)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  
>  	return nfsd4_do_encode_secinfo(xdr, secinfo->sin_exp);
>  }
> @@ -4276,7 +4276,7 @@ nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
>  static __be32
>  nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setattr *setattr)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 16);
> @@ -4300,7 +4300,7 @@ nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
>  static __be32
>  nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setclientid *scd)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	if (!nfserr) {
> @@ -4324,7 +4324,7 @@ nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct n
>  static __be32
>  nfsd4_encode_write(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_write *write)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 16);
> @@ -4341,7 +4341,7 @@ static __be32
>  nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			 struct nfsd4_exchange_id *exid)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  	char *major_id;
>  	char *server_scope;
> @@ -4419,7 +4419,7 @@ static __be32
>  nfsd4_encode_create_session(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			    struct nfsd4_create_session *sess)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 24);
> @@ -4472,7 +4472,7 @@ static __be32
>  nfsd4_encode_sequence(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		      struct nfsd4_sequence *seq)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 20);
> @@ -4495,7 +4495,7 @@ static __be32
>  nfsd4_encode_test_stateid(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			  struct nfsd4_test_stateid *test_stateid)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct nfsd4_test_stateid_id *stateid, *next;
>  	__be32 *p;
>  
> @@ -4516,7 +4516,7 @@ static __be32
>  nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		struct nfsd4_getdeviceinfo *gdev)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	const struct nfsd4_layout_ops *ops;
>  	u32 starting_len = xdr->buf->len, needed_len;
>  	__be32 *p;
> @@ -4572,7 +4572,7 @@ static __be32
>  nfsd4_encode_layoutget(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		struct nfsd4_layoutget *lgp)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	const struct nfsd4_layout_ops *ops;
>  	__be32 *p;
>  
> @@ -4599,7 +4599,7 @@ static __be32
>  nfsd4_encode_layoutcommit(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			  struct nfsd4_layoutcommit *lcp)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 4);
> @@ -4620,7 +4620,7 @@ static __be32
>  nfsd4_encode_layoutreturn(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		struct nfsd4_layoutreturn *lrp)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 4);
> @@ -4638,7 +4638,7 @@ nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
>  		struct nfsd42_write_res *write, bool sync)
>  {
>  	__be32 *p;
> -	p = xdr_reserve_space(&resp->xdr, 4);
> +	p = xdr_reserve_space(resp->xdr, 4);
>  	if (!p)
>  		return nfserr_resource;
>  
> @@ -4647,11 +4647,11 @@ nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
>  	else {
>  		__be32 nfserr;
>  		*p++ = cpu_to_be32(1);
> -		nfserr = nfsd4_encode_stateid(&resp->xdr, &write->cb_stateid);
> +		nfserr = nfsd4_encode_stateid(resp->xdr, &write->cb_stateid);
>  		if (nfserr)
>  			return nfserr;
>  	}
> -	p = xdr_reserve_space(&resp->xdr, 8 + 4 + NFS4_VERIFIER_SIZE);
> +	p = xdr_reserve_space(resp->xdr, 8 + 4 + NFS4_VERIFIER_SIZE);
>  	if (!p)
>  		return nfserr_resource;
>  
> @@ -4665,7 +4665,7 @@ nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
>  static __be32
>  nfsd42_encode_nl4_server(struct nfsd4_compoundres *resp, struct nl4_server *ns)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct nfs42_netaddr *addr;
>  	__be32 *p;
>  
> @@ -4713,7 +4713,7 @@ nfsd4_encode_copy(struct nfsd4_compoundres *resp, __be32 nfserr,
>  	if (nfserr)
>  		return nfserr;
>  
> -	p = xdr_reserve_space(&resp->xdr, 4 + 4);
> +	p = xdr_reserve_space(resp->xdr, 4 + 4);
>  	*p++ = xdr_one; /* cr_consecutive */
>  	*p++ = cpu_to_be32(copy->cp_synchronous);
>  	return 0;
> @@ -4723,7 +4723,7 @@ static __be32
>  nfsd4_encode_offload_status(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			    struct nfsd4_offload_status *os)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 8 + 4);
> @@ -4740,7 +4740,7 @@ nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
>  			    unsigned long *maxcount, u32 *eof,
>  			    loff_t *pos)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct file *file = read->rd_nf->nf_file;
>  	int starting_len = xdr->buf->len;
>  	loff_t hole_pos;
> @@ -4799,7 +4799,7 @@ nfsd4_encode_read_plus_hole(struct nfsd4_compoundres *resp,
>  	count = data_pos - read->rd_offset;
>  
>  	/* Content type, offset, byte count */
> -	p = xdr_reserve_space(&resp->xdr, 4 + 8 + 8);
> +	p = xdr_reserve_space(resp->xdr, 4 + 8 + 8);
>  	if (!p)
>  		return nfserr_resource;
>  
> @@ -4817,7 +4817,7 @@ nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		       struct nfsd4_read *read)
>  {
>  	unsigned long maxcount, count;
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct file *file;
>  	int starting_len = xdr->buf->len;
>  	int last_segment = xdr->buf->len;
> @@ -4888,7 +4888,7 @@ static __be32
>  nfsd4_encode_copy_notify(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			 struct nfsd4_copy_notify *cn)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	if (nfserr)
> @@ -4924,7 +4924,7 @@ nfsd4_encode_seek(struct nfsd4_compoundres *resp, __be32 nfserr,
>  {
>  	__be32 *p;
>  
> -	p = xdr_reserve_space(&resp->xdr, 4 + 8);
> +	p = xdr_reserve_space(resp->xdr, 4 + 8);
>  	*p++ = cpu_to_be32(seek->seek_eof);
>  	p = xdr_encode_hyper(p, seek->seek_pos);
>  
> @@ -4985,7 +4985,7 @@ static __be32
>  nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		      struct nfsd4_getxattr *getxattr)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p, err;
>  
>  	p = xdr_reserve_space(xdr, 4);
> @@ -5009,7 +5009,7 @@ static __be32
>  nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
>  		      struct nfsd4_setxattr *setxattr)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 20);
> @@ -5050,7 +5050,7 @@ static __be32
>  nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			struct nfsd4_listxattrs *listxattrs)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	u32 cookie_offset, count_offset, eof;
>  	u32 left, xdrleft, slen, count;
>  	u32 xdrlen, offset;
> @@ -5161,7 +5161,7 @@ static __be32
>  nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
>  			 struct nfsd4_removexattr *removexattr)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	__be32 *p;
>  
>  	p = xdr_reserve_space(xdr, 20);
> @@ -5301,7 +5301,7 @@ __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)
>  void
>  nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
>  {
> -	struct xdr_stream *xdr = &resp->xdr;
> +	struct xdr_stream *xdr = resp->xdr;
>  	struct nfs4_stateowner *so = resp->cstate.replay_owner;
>  	struct svc_rqst *rqstp = resp->rqstp;
>  	const struct nfsd4_operation *opdesc = op->opdesc;
> @@ -5430,14 +5430,14 @@ int
>  nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p)
>  {
>  	struct nfsd4_compoundres *resp = rqstp->rq_resp;
> -	struct xdr_buf *buf = resp->xdr.buf;
> +	struct xdr_buf *buf = resp->xdr->buf;
>  
>  	WARN_ON_ONCE(buf->len != buf->head[0].iov_len + buf->page_len +
>  				 buf->tail[0].iov_len);
>  
>  	*p = resp->cstate.status;
>  
> -	rqstp->rq_next_page = resp->xdr.page_ptr + 1;
> +	rqstp->rq_next_page = resp->xdr->page_ptr + 1;
>  
>  	p = resp->tagp;
>  	*p++ = htonl(resp->taglen);
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index 6de406322106..d909e4956244 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -997,7 +997,7 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
>  	 * NFSv4 does some encoding while processing
>  	 */
>  	p = resv->iov_base + resv->iov_len;
> -	resv->iov_len += sizeof(__be32);
> +	svcxdr_init_encode(rqstp);
>  
>  	*statp = proc->pc_func(rqstp);
>  	if (*statp == rpc_drop_reply || test_bit(RQ_DROPME, &rqstp->rq_flags))
> @@ -1052,7 +1052,7 @@ int nfssvc_decode_voidarg(struct svc_rqst *rqstp, __be32 *p)
>   */
>  int nfssvc_encode_voidres(struct svc_rqst *rqstp, __be32 *p)
>  {
> -        return xdr_ressize_check(rqstp, p);
> +	return 1;
>  }
>  
>  int nfsd_pool_stats_open(struct inode *inode, struct file *file)
> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
> index c300885ae75d..fe540a3415c6 100644
> --- a/fs/nfsd/xdr4.h
> +++ b/fs/nfsd/xdr4.h
> @@ -698,7 +698,7 @@ struct nfsd4_compoundargs {
>  
>  struct nfsd4_compoundres {
>  	/* scratch variables for XDR encode */
> -	struct xdr_stream		xdr;
> +	struct xdr_stream		*xdr;
>  	struct svc_rqst *		rqstp;
>  
>  	u32				taglen;
> diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
> index 31ee3b6047c3..e91d51ea028b 100644
> --- a/include/linux/sunrpc/svc.h
> +++ b/include/linux/sunrpc/svc.h
> @@ -248,6 +248,7 @@ struct svc_rqst {
>  	size_t			rq_xprt_hlen;	/* xprt header len */
>  	struct xdr_buf		rq_arg;
>  	struct xdr_stream	rq_arg_stream;
> +	struct xdr_stream	rq_res_stream;
>  	struct page		*rq_scratch_page;
>  	struct xdr_buf		rq_res;
>  	struct page		*rq_pages[RPCSVC_MAXPAGES + 1];
> @@ -574,4 +575,28 @@ static inline void svcxdr_init_decode(struct svc_rqst *rqstp)
>  	xdr_set_scratch_page(xdr, rqstp->rq_scratch_page);
>  }
>  
> +/**
> + * svcxdr_init_encode - Prepare an xdr_stream for svc Reply encoding
> + * @rqstp: controlling server RPC transaction context
> + *
> + */
> +static inline void svcxdr_init_encode(struct svc_rqst *rqstp)
> +{
> +	struct xdr_stream *xdr = &rqstp->rq_res_stream;
> +	struct xdr_buf *buf = &rqstp->rq_res;
> +	struct kvec *resv = buf->head;
> +
> +	xdr_reset_scratch_buffer(xdr);
> +
> +	xdr->buf = buf;
> +	xdr->iov = resv;
> +	xdr->p   = resv->iov_base + resv->iov_len;
> +	xdr->end = resv->iov_base + PAGE_SIZE - rqstp->rq_auth_slack;
> +	buf->len = resv->iov_len;
> +	xdr->page_ptr = buf->pages - 1;
> +	buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages);
> +	buf->buflen -= rqstp->rq_auth_slack;
> +	xdr->rqst = NULL;
> +}
> +
>  #endif /* SUNRPC_SVC_H */
>
Chuck Lever III March 2, 2021, 4:57 p.m. UTC | #2
> On Mar 2, 2021, at 11:47 AM, J. Bruce Fields <bfields@fieldses.org> wrote:
> 
> On Mon, Mar 01, 2021 at 10:15:24AM -0500, Chuck Lever wrote:
>> NFSD initializes an encode xdr_stream only after the RPC layer has
>> already inserted the RPC Reply header.
> 
> Out of curiosity: does it need to be this way?

The code in svc.c uses the old-school svc_putu32() and friends macros.
I don't think there's another reason.

IMHO they could be replaced, but I didn't have the stones to go that
far.


--
Chuck Lever
diff mbox series

Patch

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index acdb3cd806a1..b749033e467f 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2262,25 +2262,6 @@  static bool need_wrongsec_check(struct svc_rqst *rqstp)
 	return !(nextd->op_flags & OP_HANDLES_WRONGSEC);
 }
 
-static void svcxdr_init_encode(struct svc_rqst *rqstp,
-			       struct nfsd4_compoundres *resp)
-{
-	struct xdr_stream *xdr = &resp->xdr;
-	struct xdr_buf *buf = &rqstp->rq_res;
-	struct kvec *head = buf->head;
-
-	xdr->buf = buf;
-	xdr->iov = head;
-	xdr->p   = head->iov_base + head->iov_len;
-	xdr->end = head->iov_base + PAGE_SIZE - rqstp->rq_auth_slack;
-	/* Tail and page_len should be zero at this point: */
-	buf->len = buf->head[0].iov_len;
-	xdr_reset_scratch_buffer(xdr);
-	xdr->page_ptr = buf->pages - 1;
-	buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages)
-		- rqstp->rq_auth_slack;
-}
-
 #ifdef CONFIG_NFSD_V4_2_INTER_SSC
 static void
 check_if_stalefh_allowed(struct nfsd4_compoundargs *args)
@@ -2335,10 +2316,14 @@  nfsd4_proc_compound(struct svc_rqst *rqstp)
 	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 	__be32		status;
 
-	svcxdr_init_encode(rqstp, resp);
-	resp->tagp = resp->xdr.p;
+	resp->xdr = &rqstp->rq_res_stream;
+
+	/* reserve space for: NFS status code */
+	xdr_reserve_space(resp->xdr, XDR_UNIT);
+
+	resp->tagp = resp->xdr->p;
 	/* reserve space for: taglen, tag, and opcnt */
-	xdr_reserve_space(&resp->xdr, 8 + args->taglen);
+	xdr_reserve_space(resp->xdr, XDR_UNIT * 2 + args->taglen);
 	resp->taglen = args->taglen;
 	resp->tag = args->tag;
 	resp->rqstp = rqstp;
@@ -2444,7 +2429,7 @@  nfsd4_proc_compound(struct svc_rqst *rqstp)
 encode_op:
 		if (op->status == nfserr_replay_me) {
 			op->replay = &cstate->replay_owner->so_replay;
-			nfsd4_encode_replay(&resp->xdr, op);
+			nfsd4_encode_replay(resp->xdr, op);
 			status = op->status = op->replay->rp_status;
 		} else {
 			nfsd4_encode_operation(resp, op);
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 61552e89bd89..83a498ccab19 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2903,7 +2903,7 @@  gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, struct svc_r
 static void
 nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
 {
-	struct xdr_buf *buf = resp->xdr.buf;
+	struct xdr_buf *buf = resp->xdr->buf;
 	struct nfsd4_slot *slot = resp->cstate.slot;
 	unsigned int base;
 
@@ -2973,7 +2973,7 @@  nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
 			 struct nfsd4_sequence *seq)
 {
 	struct nfsd4_slot *slot = resp->cstate.slot;
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 	__be32 status;
 
@@ -3708,7 +3708,7 @@  nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 {
 	struct nfsd4_sequence *seq = &u->sequence;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct nfsd4_session *session;
 	struct nfs4_client *clp;
 	struct nfsd4_slot *slot;
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index eaaa1605b5b5..e0f06d3cbd44 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3581,7 +3581,7 @@  nfsd4_encode_stateid(struct xdr_stream *xdr, stateid_t *sid)
 static __be32
 nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_access *access)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 8);
@@ -3594,7 +3594,7 @@  nfsd4_encode_access(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_
 
 static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_bind_conn_to_session *bcts)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 8);
@@ -3611,7 +3611,7 @@  static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp,
 static __be32
 nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_close *close)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	return nfsd4_encode_stateid(xdr, &close->cl_stateid);
 }
@@ -3620,7 +3620,7 @@  nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_c
 static __be32
 nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_commit *commit)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
@@ -3634,7 +3634,7 @@  nfsd4_encode_commit(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_
 static __be32
 nfsd4_encode_create(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_create *create)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 20);
@@ -3649,7 +3649,7 @@  static __be32
 nfsd4_encode_getattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_getattr *getattr)
 {
 	struct svc_fh *fhp = getattr->ga_fhp;
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	return nfsd4_encode_fattr(xdr, fhp, fhp->fh_export, fhp->fh_dentry,
 				    getattr->ga_bmval, resp->rqstp, 0);
@@ -3658,7 +3658,7 @@  nfsd4_encode_getattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
 static __be32
 nfsd4_encode_getfh(struct nfsd4_compoundres *resp, __be32 nfserr, struct svc_fh **fhpp)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct svc_fh *fhp = *fhpp;
 	unsigned int len;
 	__be32 *p;
@@ -3713,7 +3713,7 @@  nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
 static __be32
 nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lock *lock)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	if (!nfserr)
 		nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid);
@@ -3726,7 +3726,7 @@  nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lo
 static __be32
 nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lockt *lockt)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	if (nfserr == nfserr_denied)
 		nfsd4_encode_lock_denied(xdr, &lockt->lt_denied);
@@ -3736,7 +3736,7 @@  nfsd4_encode_lockt(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_l
 static __be32
 nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_locku *locku)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	return nfsd4_encode_stateid(xdr, &locku->lu_stateid);
 }
@@ -3745,7 +3745,7 @@  nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_l
 static __be32
 nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_link *link)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 20);
@@ -3759,7 +3759,7 @@  nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_li
 static __be32
 nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open *open)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	nfserr = nfsd4_encode_stateid(xdr, &open->op_stateid);
@@ -3853,7 +3853,7 @@  nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_op
 static __be32
 nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_confirm *oc)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	return nfsd4_encode_stateid(xdr, &oc->oc_resp_stateid);
 }
@@ -3861,7 +3861,7 @@  nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct
 static __be32
 nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_open_downgrade *od)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	return nfsd4_encode_stateid(xdr, &od->od_stateid);
 }
@@ -3871,7 +3871,7 @@  static __be32 nfsd4_encode_splice_read(
 				struct nfsd4_read *read,
 				struct file *file, unsigned long maxcount)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct xdr_buf *buf = xdr->buf;
 	int status, space_left;
 	u32 eof;
@@ -3937,7 +3937,7 @@  static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 				 struct nfsd4_read *read,
 				 struct file *file, unsigned long maxcount)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	u32 eof;
 	int starting_len = xdr->buf->len - 8;
 	__be32 nfserr;
@@ -3976,7 +3976,7 @@  nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
 		  struct nfsd4_read *read)
 {
 	unsigned long maxcount;
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct file *file;
 	int starting_len = xdr->buf->len;
 	__be32 *p;
@@ -3990,7 +3990,7 @@  nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
 		WARN_ON_ONCE(test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags));
 		return nfserr_resource;
 	}
-	if (resp->xdr.buf->page_len &&
+	if (resp->xdr->buf->page_len &&
 	    test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags)) {
 		WARN_ON_ONCE(1);
 		return nfserr_resource;
@@ -4020,7 +4020,7 @@  nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
 	int maxcount;
 	__be32 wire_count;
 	int zero = 0;
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	int length_offset = xdr->buf->len;
 	int status;
 	__be32 *p;
@@ -4072,7 +4072,7 @@  nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
 	int bytes_left;
 	loff_t offset;
 	__be64 wire_offset;
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	int starting_len = xdr->buf->len;
 	__be32 *p;
 
@@ -4083,8 +4083,8 @@  nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
 	/* XXX: Following NFSv3, we ignore the READDIR verifier for now. */
 	*p++ = cpu_to_be32(0);
 	*p++ = cpu_to_be32(0);
-	resp->xdr.buf->head[0].iov_len = ((char *)resp->xdr.p)
-				- (char *)resp->xdr.buf->head[0].iov_base;
+	xdr->buf->head[0].iov_len = (char *)xdr->p -
+				    (char *)xdr->buf->head[0].iov_base;
 
 	/*
 	 * Number of bytes left for directory entries allowing for the
@@ -4159,7 +4159,7 @@  nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
 static __be32
 nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_remove *remove)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 20);
@@ -4172,7 +4172,7 @@  nfsd4_encode_remove(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_
 static __be32
 nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_rename *rename)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 40);
@@ -4255,7 +4255,7 @@  static __be32
 nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
 		     struct nfsd4_secinfo *secinfo)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	return nfsd4_do_encode_secinfo(xdr, secinfo->si_exp);
 }
@@ -4264,7 +4264,7 @@  static __be32
 nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
 		     struct nfsd4_secinfo_no_name *secinfo)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 
 	return nfsd4_do_encode_secinfo(xdr, secinfo->sin_exp);
 }
@@ -4276,7 +4276,7 @@  nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
 static __be32
 nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setattr *setattr)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 16);
@@ -4300,7 +4300,7 @@  nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
 static __be32
 nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_setclientid *scd)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	if (!nfserr) {
@@ -4324,7 +4324,7 @@  nfsd4_encode_setclientid(struct nfsd4_compoundres *resp, __be32 nfserr, struct n
 static __be32
 nfsd4_encode_write(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_write *write)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 16);
@@ -4341,7 +4341,7 @@  static __be32
 nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
 			 struct nfsd4_exchange_id *exid)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 	char *major_id;
 	char *server_scope;
@@ -4419,7 +4419,7 @@  static __be32
 nfsd4_encode_create_session(struct nfsd4_compoundres *resp, __be32 nfserr,
 			    struct nfsd4_create_session *sess)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 24);
@@ -4472,7 +4472,7 @@  static __be32
 nfsd4_encode_sequence(struct nfsd4_compoundres *resp, __be32 nfserr,
 		      struct nfsd4_sequence *seq)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN + 20);
@@ -4495,7 +4495,7 @@  static __be32
 nfsd4_encode_test_stateid(struct nfsd4_compoundres *resp, __be32 nfserr,
 			  struct nfsd4_test_stateid *test_stateid)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct nfsd4_test_stateid_id *stateid, *next;
 	__be32 *p;
 
@@ -4516,7 +4516,7 @@  static __be32
 nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
 		struct nfsd4_getdeviceinfo *gdev)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	const struct nfsd4_layout_ops *ops;
 	u32 starting_len = xdr->buf->len, needed_len;
 	__be32 *p;
@@ -4572,7 +4572,7 @@  static __be32
 nfsd4_encode_layoutget(struct nfsd4_compoundres *resp, __be32 nfserr,
 		struct nfsd4_layoutget *lgp)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	const struct nfsd4_layout_ops *ops;
 	__be32 *p;
 
@@ -4599,7 +4599,7 @@  static __be32
 nfsd4_encode_layoutcommit(struct nfsd4_compoundres *resp, __be32 nfserr,
 			  struct nfsd4_layoutcommit *lcp)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 4);
@@ -4620,7 +4620,7 @@  static __be32
 nfsd4_encode_layoutreturn(struct nfsd4_compoundres *resp, __be32 nfserr,
 		struct nfsd4_layoutreturn *lrp)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 4);
@@ -4638,7 +4638,7 @@  nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
 		struct nfsd42_write_res *write, bool sync)
 {
 	__be32 *p;
-	p = xdr_reserve_space(&resp->xdr, 4);
+	p = xdr_reserve_space(resp->xdr, 4);
 	if (!p)
 		return nfserr_resource;
 
@@ -4647,11 +4647,11 @@  nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
 	else {
 		__be32 nfserr;
 		*p++ = cpu_to_be32(1);
-		nfserr = nfsd4_encode_stateid(&resp->xdr, &write->cb_stateid);
+		nfserr = nfsd4_encode_stateid(resp->xdr, &write->cb_stateid);
 		if (nfserr)
 			return nfserr;
 	}
-	p = xdr_reserve_space(&resp->xdr, 8 + 4 + NFS4_VERIFIER_SIZE);
+	p = xdr_reserve_space(resp->xdr, 8 + 4 + NFS4_VERIFIER_SIZE);
 	if (!p)
 		return nfserr_resource;
 
@@ -4665,7 +4665,7 @@  nfsd42_encode_write_res(struct nfsd4_compoundres *resp,
 static __be32
 nfsd42_encode_nl4_server(struct nfsd4_compoundres *resp, struct nl4_server *ns)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct nfs42_netaddr *addr;
 	__be32 *p;
 
@@ -4713,7 +4713,7 @@  nfsd4_encode_copy(struct nfsd4_compoundres *resp, __be32 nfserr,
 	if (nfserr)
 		return nfserr;
 
-	p = xdr_reserve_space(&resp->xdr, 4 + 4);
+	p = xdr_reserve_space(resp->xdr, 4 + 4);
 	*p++ = xdr_one; /* cr_consecutive */
 	*p++ = cpu_to_be32(copy->cp_synchronous);
 	return 0;
@@ -4723,7 +4723,7 @@  static __be32
 nfsd4_encode_offload_status(struct nfsd4_compoundres *resp, __be32 nfserr,
 			    struct nfsd4_offload_status *os)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 8 + 4);
@@ -4740,7 +4740,7 @@  nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
 			    unsigned long *maxcount, u32 *eof,
 			    loff_t *pos)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct file *file = read->rd_nf->nf_file;
 	int starting_len = xdr->buf->len;
 	loff_t hole_pos;
@@ -4799,7 +4799,7 @@  nfsd4_encode_read_plus_hole(struct nfsd4_compoundres *resp,
 	count = data_pos - read->rd_offset;
 
 	/* Content type, offset, byte count */
-	p = xdr_reserve_space(&resp->xdr, 4 + 8 + 8);
+	p = xdr_reserve_space(resp->xdr, 4 + 8 + 8);
 	if (!p)
 		return nfserr_resource;
 
@@ -4817,7 +4817,7 @@  nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
 		       struct nfsd4_read *read)
 {
 	unsigned long maxcount, count;
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct file *file;
 	int starting_len = xdr->buf->len;
 	int last_segment = xdr->buf->len;
@@ -4888,7 +4888,7 @@  static __be32
 nfsd4_encode_copy_notify(struct nfsd4_compoundres *resp, __be32 nfserr,
 			 struct nfsd4_copy_notify *cn)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	if (nfserr)
@@ -4924,7 +4924,7 @@  nfsd4_encode_seek(struct nfsd4_compoundres *resp, __be32 nfserr,
 {
 	__be32 *p;
 
-	p = xdr_reserve_space(&resp->xdr, 4 + 8);
+	p = xdr_reserve_space(resp->xdr, 4 + 8);
 	*p++ = cpu_to_be32(seek->seek_eof);
 	p = xdr_encode_hyper(p, seek->seek_pos);
 
@@ -4985,7 +4985,7 @@  static __be32
 nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
 		      struct nfsd4_getxattr *getxattr)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p, err;
 
 	p = xdr_reserve_space(xdr, 4);
@@ -5009,7 +5009,7 @@  static __be32
 nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
 		      struct nfsd4_setxattr *setxattr)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 20);
@@ -5050,7 +5050,7 @@  static __be32
 nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
 			struct nfsd4_listxattrs *listxattrs)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	u32 cookie_offset, count_offset, eof;
 	u32 left, xdrleft, slen, count;
 	u32 xdrlen, offset;
@@ -5161,7 +5161,7 @@  static __be32
 nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
 			 struct nfsd4_removexattr *removexattr)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 20);
@@ -5301,7 +5301,7 @@  __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)
 void
 nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
 {
-	struct xdr_stream *xdr = &resp->xdr;
+	struct xdr_stream *xdr = resp->xdr;
 	struct nfs4_stateowner *so = resp->cstate.replay_owner;
 	struct svc_rqst *rqstp = resp->rqstp;
 	const struct nfsd4_operation *opdesc = op->opdesc;
@@ -5430,14 +5430,14 @@  int
 nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
-	struct xdr_buf *buf = resp->xdr.buf;
+	struct xdr_buf *buf = resp->xdr->buf;
 
 	WARN_ON_ONCE(buf->len != buf->head[0].iov_len + buf->page_len +
 				 buf->tail[0].iov_len);
 
 	*p = resp->cstate.status;
 
-	rqstp->rq_next_page = resp->xdr.page_ptr + 1;
+	rqstp->rq_next_page = resp->xdr->page_ptr + 1;
 
 	p = resp->tagp;
 	*p++ = htonl(resp->taglen);
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 6de406322106..d909e4956244 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -997,7 +997,7 @@  int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 	 * NFSv4 does some encoding while processing
 	 */
 	p = resv->iov_base + resv->iov_len;
-	resv->iov_len += sizeof(__be32);
+	svcxdr_init_encode(rqstp);
 
 	*statp = proc->pc_func(rqstp);
 	if (*statp == rpc_drop_reply || test_bit(RQ_DROPME, &rqstp->rq_flags))
@@ -1052,7 +1052,7 @@  int nfssvc_decode_voidarg(struct svc_rqst *rqstp, __be32 *p)
  */
 int nfssvc_encode_voidres(struct svc_rqst *rqstp, __be32 *p)
 {
-        return xdr_ressize_check(rqstp, p);
+	return 1;
 }
 
 int nfsd_pool_stats_open(struct inode *inode, struct file *file)
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index c300885ae75d..fe540a3415c6 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -698,7 +698,7 @@  struct nfsd4_compoundargs {
 
 struct nfsd4_compoundres {
 	/* scratch variables for XDR encode */
-	struct xdr_stream		xdr;
+	struct xdr_stream		*xdr;
 	struct svc_rqst *		rqstp;
 
 	u32				taglen;
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 31ee3b6047c3..e91d51ea028b 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -248,6 +248,7 @@  struct svc_rqst {
 	size_t			rq_xprt_hlen;	/* xprt header len */
 	struct xdr_buf		rq_arg;
 	struct xdr_stream	rq_arg_stream;
+	struct xdr_stream	rq_res_stream;
 	struct page		*rq_scratch_page;
 	struct xdr_buf		rq_res;
 	struct page		*rq_pages[RPCSVC_MAXPAGES + 1];
@@ -574,4 +575,28 @@  static inline void svcxdr_init_decode(struct svc_rqst *rqstp)
 	xdr_set_scratch_page(xdr, rqstp->rq_scratch_page);
 }
 
+/**
+ * svcxdr_init_encode - Prepare an xdr_stream for svc Reply encoding
+ * @rqstp: controlling server RPC transaction context
+ *
+ */
+static inline void svcxdr_init_encode(struct svc_rqst *rqstp)
+{
+	struct xdr_stream *xdr = &rqstp->rq_res_stream;
+	struct xdr_buf *buf = &rqstp->rq_res;
+	struct kvec *resv = buf->head;
+
+	xdr_reset_scratch_buffer(xdr);
+
+	xdr->buf = buf;
+	xdr->iov = resv;
+	xdr->p   = resv->iov_base + resv->iov_len;
+	xdr->end = resv->iov_base + PAGE_SIZE - rqstp->rq_auth_slack;
+	buf->len = resv->iov_len;
+	xdr->page_ptr = buf->pages - 1;
+	buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages);
+	buf->buflen -= rqstp->rq_auth_slack;
+	xdr->rqst = NULL;
+}
+
 #endif /* SUNRPC_SVC_H */