NFSD: Update READLINK3arg decoder to use struct xdr_stream

The NFSv3 READLINK request takes a single filehandle, so it can
re-use GETATTR's decoder.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs3proc.c

@@ -124,15 +124,16 @@ nfsd3_proc_access(struct svc_rqst *rqstp)
 static __be32
 nfsd3_proc_readlink(struct svc_rqst *rqstp)
 {
-	struct nfsd3_readlinkargs *argp = rqstp->rq_argp;
+	struct nfsd_fhandle *argp = rqstp->rq_argp;
 	struct nfsd3_readlinkres *resp = rqstp->rq_resp;
+	char *buffer = page_address(*(rqstp->rq_next_page++));
 
 	dprintk("nfsd: READLINK(3) %s\n", SVCFH_fmt(&argp->fh));
 
 	/* Read the symlink. */
 	fh_copy(&resp->fh, &argp->fh);
 	resp->len = NFS3_MAXPATHLEN;
-	resp->status = nfsd_readlink(rqstp, &resp->fh, argp->buffer, &resp->len);
+	resp->status = nfsd_readlink(rqstp, &resp->fh, buffer, &resp->len);
 	return rpc_success;
 }
 
@@ -768,10 +769,10 @@ static const struct svc_procedure nfsd_procedures3[22] = {
 	},
 	[NFS3PROC_READLINK] = {
 		.pc_func = nfsd3_proc_readlink,
-		.pc_decode = nfs3svc_decode_readlinkargs,
+		.pc_decode = nfs3svc_decode_fhandleargs,
 		.pc_encode = nfs3svc_encode_readlinkres,
 		.pc_release = nfs3svc_release_fhandle,
-		.pc_argsize = sizeof(struct nfsd3_readlinkargs),
+		.pc_argsize = sizeof(struct nfsd_fhandle),
 		.pc_ressize = sizeof(struct nfsd3_readlinkres),
 		.pc_cachetype = RC_NOCACHE,
 		.pc_xdrressize = ST+pAT+1+NFS3_MAXPATHLEN/4,

fs/nfsd/nfs3xdr.c

@@ -543,19 +543,6 @@ nfs3svc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
 	return xdr_argsize_check(rqstp, p);
 }
 
-int
-nfs3svc_decode_readlinkargs(struct svc_rqst *rqstp, __be32 *p)
-{
-	struct nfsd3_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
 nfs3svc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
 {

fs/nfsd/xdr3.h

@@ -70,11 +70,6 @@ struct nfsd3_renameargs {
 	unsigned int		tlen;
 };
 
-struct nfsd3_readlinkargs {
-	struct svc_fh		fh;
-	char *			buffer;
-};
-
 struct nfsd3_linkargs {
 	struct svc_fh		ffh;
 	struct svc_fh		tfh;
@@ -282,7 +277,6 @@ int nfs3svc_decode_createargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_mkdirargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_mknodargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_renameargs(struct svc_rqst *, __be32 *);
-int nfs3svc_decode_readlinkargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_linkargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_symlinkargs(struct svc_rqst *, __be32 *);
 int nfs3svc_decode_readdirargs(struct svc_rqst *, __be32 *);