SUNRPC: Refactor RPC server dispatch method

Currently, svcauth_gss_accept() pre-reserves response buffer space
for the RPC payload length and GSS sequence number before returning
to the dispatcher, which then adds the header's accept_stat field.

The problem is the accept_stat field is supposed to go before the
length and seq_num fields. So svcauth_gss_release() has to relocate
the accept_stat value (see svcauth_gss_prepare_to_wrap()).

To enable these fields to be added to the response buffer in the
correct (final) order, the pointer to the accept_stat has to be made
available to svcauth_gss_accept() so that it can set it before
reserving space for the length and seq_num fields.

As a first step, move the pointer to the location of the accept_stat
field into struct svc_rqst.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

5 files changed, 8 insertions, 8 deletions

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 642e394e7a2d..0b28a6cf9303 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -685,15 +685,15 @@ module_exit(exit_nlm);
 /**
  * nlmsvc_dispatch - Process an NLM Request
  * @rqstp: incoming request
- * @statp: pointer to location of accept_stat field in RPC Reply buffer
  *
  * Return values:
  *  %0: Processing complete; do not send a Reply
  *  %1: Processing complete; send Reply in rqstp->rq_res
  */
-static int nlmsvc_dispatch(struct svc_rqst *rqstp, __be32 *statp)
+static int nlmsvc_dispatch(struct svc_rqst *rqstp)
 {
 	const struct svc_procedure *procp = rqstp->rq_procinfo;
+	__be32 *statp = rqstp->rq_accept_statp;
 
 	if (!procp->pc_decode(rqstp, &rqstp->rq_arg_stream))
 		goto out_decode_err;
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index b4c3b7182198..13b2af55497d 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -980,11 +980,11 @@ out_invalidcred:
 }
 
 static int
-nfs_callback_dispatch(struct svc_rqst *rqstp, __be32 *statp)
+nfs_callback_dispatch(struct svc_rqst *rqstp)
 {
 	const struct svc_procedure *procp = rqstp->rq_procinfo;
 
-	*statp = procp->pc_func(rqstp);
+	*rqstp->rq_accept_statp = procp->pc_func(rqstp);
 	return 1;
 }
 
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index ef5ee548053b..041faa13b852 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -509,7 +509,7 @@ out_trace:
  * nfsd_cache_update - Update an entry in the duplicate reply cache.
  * @rqstp: svc_rqst with a finished Reply
  * @cachetype: which cache to update
- * @statp: Reply's status code
+ * @statp: pointer to Reply's NFS status code, or NULL
  *
  * This is called from nfsd_dispatch when the procedure has been
  * executed and the complete reply is in rqstp->rq_res.
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index fa0144a74267..d88498f8b275 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -86,7 +86,7 @@ bool		nfssvc_encode_voidres(struct svc_rqst *rqstp,
  * Function prototypes.
  */
 int		nfsd_svc(int nrservs, struct net *net, const struct cred *cred);
-int		nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp);
+int		nfsd_dispatch(struct svc_rqst *rqstp);
 
 int		nfsd_nrthreads(struct net *);
 int		nfsd_nrpools(struct net *);
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index dfa8ee6c04d5..ff10c46b62d3 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -1022,7 +1022,6 @@ out:
 /**
  * nfsd_dispatch - Process an NFS or NFSACL Request
  * @rqstp: incoming request
- * @statp: pointer to location of accept_stat field in RPC Reply buffer
  *
  * This RPC dispatcher integrates the NFS server's duplicate reply cache.
  *
@@ -1030,9 +1029,10 @@ out:
  *  %0: Processing complete; do not send a Reply
  *  %1: Processing complete; send Reply in rqstp->rq_res
  */
-int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
+int nfsd_dispatch(struct svc_rqst *rqstp)
 {
 	const struct svc_procedure *proc = rqstp->rq_procinfo;
+	__be32 *statp = rqstp->rq_accept_statp;
 
 	/*
 	 * Give the xdr decoder a chance to change this if it wants