NFSD: Use const pointers as parameters to fh_ helpers

Enable callers to use const pointers where they are able to.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>

fs/nfsd/nfsfh.h

@@ -220,7 +220,7 @@ __be32	fh_update(struct svc_fh *);
 void	fh_put(struct svc_fh *);
 
 static __inline__ struct svc_fh *
-fh_copy(struct svc_fh *dst, struct svc_fh *src)
+fh_copy(struct svc_fh *dst, const struct svc_fh *src)
 {
 	WARN_ON(src->fh_dentry);
 
@@ -229,7 +229,7 @@ fh_copy(struct svc_fh *dst, struct svc_fh *src)
 }
 
 static inline void
-fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
+fh_copy_shallow(struct knfsd_fh *dst, const struct knfsd_fh *src)
 {
 	dst->fh_size = src->fh_size;
 	memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
@@ -243,7 +243,8 @@ fh_init(struct svc_fh *fhp, int maxsize)
 	return fhp;
 }
 
-static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
+static inline bool fh_match(const struct knfsd_fh *fh1,
+			    const struct knfsd_fh *fh2)
 {
 	if (fh1->fh_size != fh2->fh_size)
 		return false;
@@ -252,7 +253,8 @@ static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 	return true;
 }
 
-static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
+static inline bool fh_fsid_match(const struct knfsd_fh *fh1,
+				 const struct knfsd_fh *fh2)
 {
 	if (fh1->fh_fsid_type != fh2->fh_fsid_type)
 		return false;