NFSD: Remove svc_rqst::rq_cacherep

Over time I'd like to see NFS-specific fields moved out of struct
svc_rqst, which is an RPC layer object. These fields are layering
violations.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/cache.h

@@ -84,8 +84,10 @@ int	nfsd_net_reply_cache_init(struct nfsd_net *nn);
 void	nfsd_net_reply_cache_destroy(struct nfsd_net *nn);
 int	nfsd_reply_cache_init(struct nfsd_net *);
 void	nfsd_reply_cache_shutdown(struct nfsd_net *);
-int	nfsd_cache_lookup(struct svc_rqst *);
-void	nfsd_cache_update(struct svc_rqst *, int, __be32 *);
+int	nfsd_cache_lookup(struct svc_rqst *rqstp,
+			  struct svc_cacherep **cacherep);
+void	nfsd_cache_update(struct svc_rqst *rqstp, struct svc_cacherep *rp,
+			  int cachetype, __be32 *statp);
 int	nfsd_reply_cache_stats_show(struct seq_file *m, void *v);
 
 #endif /* NFSCACHE_H */

fs/nfsd/nfscache.c

@@ -465,6 +465,7 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key,
 /**
  * nfsd_cache_lookup - Find an entry in the duplicate reply cache
  * @rqstp: Incoming Call to find
+ * @cacherep: OUT: DRC entry for this request
  *
  * Try to find an entry matching the current call in the cache. When none
  * is found, we try to grab the oldest expired entry off the LRU list. If
@@ -477,7 +478,7 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key,
  *   %RC_REPLY: Reply from cache
  *   %RC_DROPIT: Do not process the request further
  */
-int nfsd_cache_lookup(struct svc_rqst *rqstp)
+int nfsd_cache_lookup(struct svc_rqst *rqstp, struct svc_cacherep **cacherep)
 {
 	struct nfsd_net		*nn;
 	struct svc_cacherep	*rp, *found;
@@ -488,7 +489,6 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
 	LIST_HEAD(dispose);
 	int rtn = RC_DOIT;
 
-	rqstp->rq_cacherep = NULL;
 	if (type == RC_NOCACHE) {
 		nfsd_stats_rc_nocache_inc();
 		goto out;
@@ -510,7 +510,7 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
 	found = nfsd_cache_insert(b, rp, nn);
 	if (found != rp)
 		goto found_entry;
-	rqstp->rq_cacherep = rp;
+	*cacherep = rp;
 	rp->c_state = RC_INPROG;
 	nfsd_prune_bucket_locked(nn, b, 3, &dispose);
 	spin_unlock(&b->cache_lock);
@@ -568,6 +568,7 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
 /**
  * nfsd_cache_update - Update an entry in the duplicate reply cache.
  * @rqstp: svc_rqst with a finished Reply
+ * @rp: IN: DRC entry for this request
  * @cachetype: which cache to update
  * @statp: pointer to Reply's NFS status code, or NULL
  *
@@ -585,10 +586,10 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
  * nfsd failed to encode a reply that otherwise would have been cached.
  * In this case, nfsd_cache_update is called with statp == NULL.
  */
-void nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
+void nfsd_cache_update(struct svc_rqst *rqstp, struct svc_cacherep *rp,
+		       int cachetype, __be32 *statp)
 {
 	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
-	struct svc_cacherep *rp = rqstp->rq_cacherep;
 	struct kvec	*resv = &rqstp->rq_res.head[0], *cachv;
 	struct nfsd_drc_bucket *b;
 	int		len;

fs/nfsd/nfssvc.c

@@ -1046,6 +1046,7 @@ int nfsd_dispatch(struct svc_rqst *rqstp)
 {
 	const struct svc_procedure *proc = rqstp->rq_procinfo;
 	__be32 *statp = rqstp->rq_accept_statp;
+	struct svc_cacherep *rp;
 
 	/*
 	 * Give the xdr decoder a chance to change this if it wants
@@ -1056,7 +1057,8 @@ int nfsd_dispatch(struct svc_rqst *rqstp)
 	if (!proc->pc_decode(rqstp, &rqstp->rq_arg_stream))
 		goto out_decode_err;
 
-	switch (nfsd_cache_lookup(rqstp)) {
+	rp = NULL;
+	switch (nfsd_cache_lookup(rqstp, &rp)) {
 	case RC_DOIT:
 		break;
 	case RC_REPLY:
@@ -1072,7 +1074,7 @@ int nfsd_dispatch(struct svc_rqst *rqstp)
 	if (!proc->pc_encode(rqstp, &rqstp->rq_res_stream))
 		goto out_encode_err;
 
-	nfsd_cache_update(rqstp, rqstp->rq_cachetype, statp + 1);
+	nfsd_cache_update(rqstp, rp, rqstp->rq_cachetype, statp + 1);
 out_cached_reply:
 	return 1;
 
@@ -1082,13 +1084,13 @@ int nfsd_dispatch(struct svc_rqst *rqstp)
 	return 1;
 
 out_update_drop:
-	nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
+	nfsd_cache_update(rqstp, rp, RC_NOCACHE, NULL);
 out_dropit:
 	return 0;
 
 out_encode_err:
 	trace_nfsd_cant_encode_err(rqstp);
-	nfsd_cache_update(rqstp, RC_NOCACHE, NULL);
+	nfsd_cache_update(rqstp, rp, RC_NOCACHE, NULL);
 	*statp = rpc_system_err;
 	return 1;
 }

include/linux/sunrpc/svc.h

@@ -265,7 +265,6 @@ struct svc_rqst {
 	/* Catering to nfsd */
 	struct auth_domain *	rq_client;	/* RPC peer info */
 	struct auth_domain *	rq_gssclient;	/* "gss/"-style peer info */
-	struct svc_cacherep *	rq_cacherep;	/* cache info */
 	struct task_struct	*rq_task;	/* service thread */
 	struct net		*rq_bc_net;	/* pointer to backchannel's
 						 * net namespace