NFSD: Update the NFSv2 READLINK argument decoder to use struct xdr_stream

If the code that sets up the sink buffer for nfsd_readlink() is
moved adjacent to the nfsd_readlink() call site that uses it, then
the only argument is a file handle, and the fhandle decoder can be
used instead.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfsproc.c

@@ -149,14 +149,15 @@ nfsd_proc_lookup(struct svc_rqst *rqstp)
 static __be32
 nfsd_proc_readlink(struct svc_rqst *rqstp)
 {
-	struct nfsd_readlinkargs *argp = rqstp->rq_argp;
+	struct nfsd_fhandle *argp = rqstp->rq_argp;
 	struct nfsd_readlinkres *resp = rqstp->rq_resp;
+	char *buffer = page_address(*(rqstp->rq_next_page++));
 
 	dprintk("nfsd: READLINK %s\n", SVCFH_fmt(&argp->fh));
 
 	/* Read the symlink. */
 	resp->len = NFS_MAXPATHLEN;
-	resp->status = nfsd_readlink(rqstp, &argp->fh, argp->buffer, &resp->len);
+	resp->status = nfsd_readlink(rqstp, &argp->fh, buffer, &resp->len);
 
 	fh_put(&argp->fh);
 	return rpc_success;
@@ -674,9 +675,9 @@ static const struct svc_procedure nfsd_procedures2[18] = {
 	},
 	[NFSPROC_READLINK] = {
 		.pc_func = nfsd_proc_readlink,
-		.pc_decode = nfssvc_decode_readlinkargs,
+		.pc_decode = nfssvc_decode_fhandleargs,
 		.pc_encode = nfssvc_encode_readlinkres,
-		.pc_argsize = sizeof(struct nfsd_readlinkargs),
+		.pc_argsize = sizeof(struct nfsd_fhandle),
 		.pc_ressize = sizeof(struct nfsd_readlinkres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = ST+1+NFS_MAXPATHLEN/4,

fs/nfsd/nfsxdr.c

@@ -326,19 +326,6 @@ nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
 	return xdr_argsize_check(rqstp, p);
 }
 
-int
-nfssvc_decode_readlinkargs(struct svc_rqst *rqstp, __be32 *p)
-{
-	struct nfsd_readlinkargs *args = rqstp->rq_argp;
-
-	p = decode_fh(p, &args->fh);
-	if (!p)
-		return 0;
-	args->buffer = page_address(*(rqstp->rq_next_page++));
-
-	return xdr_argsize_check(rqstp, p);
-}
-
 int
 nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
 {

fs/nfsd/xdr.h

@@ -52,11 +52,6 @@ struct nfsd_renameargs {
 	unsigned int		tlen;
 };
 
-struct nfsd_readlinkargs {
-	struct svc_fh		fh;
-	char *			buffer;
-};
-	
 struct nfsd_linkargs {
 	struct svc_fh		ffh;
 	struct svc_fh		tfh;
@@ -150,7 +145,6 @@ int nfssvc_decode_readargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_writeargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_createargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_renameargs(struct svc_rqst *, __be32 *);
-int nfssvc_decode_readlinkargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_linkargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_symlinkargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_readdirargs(struct svc_rqst *, __be32 *);