NFSD: Make @gdev parameter of ->encode_getdeviceinfo a const pointer

This enables callers to be passed const pointer parameters.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/blocklayoutxdr.c

@@ -77,7 +77,7 @@ nfsd4_block_encode_volume(struct xdr_stream *xdr, struct pnfs_block_volume *b)
 
 __be32
 nfsd4_block_encode_getdeviceinfo(struct xdr_stream *xdr,
-		struct nfsd4_getdeviceinfo *gdp)
+		const struct nfsd4_getdeviceinfo *gdp)
 {
 	struct pnfs_block_deviceaddr *dev = gdp->gd_device;
 	int len = sizeof(__be32), ret, i;

fs/nfsd/blocklayoutxdr.h

@@ -51,7 +51,7 @@ struct pnfs_block_deviceaddr {
 };
 
 __be32 nfsd4_block_encode_getdeviceinfo(struct xdr_stream *xdr,
-		struct nfsd4_getdeviceinfo *gdp);
+		const struct nfsd4_getdeviceinfo *gdp);
 __be32 nfsd4_block_encode_layoutget(struct xdr_stream *xdr,
 		const struct nfsd4_layoutget *lgp);
 int nfsd4_block_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,

fs/nfsd/flexfilelayoutxdr.c

@@ -77,7 +77,7 @@ nfsd4_ff_encode_layoutget(struct xdr_stream *xdr,
 
 __be32
 nfsd4_ff_encode_getdeviceinfo(struct xdr_stream *xdr,
-		struct nfsd4_getdeviceinfo *gdp)
+		const struct nfsd4_getdeviceinfo *gdp)
 {
 	struct pnfs_ff_device_addr *da = gdp->gd_device;
 	int len;

fs/nfsd/flexfilelayoutxdr.h

@@ -43,7 +43,7 @@ struct pnfs_ff_layout {
 };
 
 __be32 nfsd4_ff_encode_getdeviceinfo(struct xdr_stream *xdr,
-		struct nfsd4_getdeviceinfo *gdp);
+		const struct nfsd4_getdeviceinfo *gdp);
 __be32 nfsd4_ff_encode_layoutget(struct xdr_stream *xdr,
 		const struct nfsd4_layoutget *lgp);
 

fs/nfsd/pnfs.h

@@ -27,7 +27,7 @@ struct nfsd4_layout_ops {
 			struct nfs4_client *clp,
 			struct nfsd4_getdeviceinfo *gdevp);
 	__be32 (*encode_getdeviceinfo)(struct xdr_stream *xdr,
-			struct nfsd4_getdeviceinfo *gdevp);
+			const struct nfsd4_getdeviceinfo *gdevp);
 
 	__be32 (*proc_layoutget)(struct inode *, const struct svc_fh *fhp,
 			struct nfsd4_layoutget *lgp);