Address several compiler warnings across NFS and MACB drivers to
enable a cleaner build:

- nfs: add __maybe_unused to 'err' in flexfilelayout.c
- nfs: add __maybe_unused to 'ret' in flexfilelayoutdev.c
- nfs: add __maybe_unused to 'ptr' in nfs4proc.c
- macb: use precision specifier in snprintf to ensure string fits
  within ETH_GSTRING_LEN (32 bytes) in macb_main.c

Signed-off-by: Sean Chang <seanwascoding@gmail.com>
---
 drivers/net/ethernet/cadence/macb_main.c  | 4 ++--
 fs/nfs/flexfilelayout/flexfilelayout.c    | 2 +-
 fs/nfs/flexfilelayout/flexfilelayoutdev.c | 3 ++-
 fs/nfs/nfs4proc.c                         | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 43cd013bb70e..26f9ccadd9f6 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -3159,8 +3159,8 @@ static void gem_get_ethtool_strings(struct net_device *dev, u32 sset, u8 *p)
 
 		for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
 			for (i = 0; i < QUEUE_STATS_LEN; i++, p += ETH_GSTRING_LEN) {
-				snprintf(stat_string, ETH_GSTRING_LEN, "q%d_%s",
-						q, queue_statistics[i].stat_string);
+				snprintf(stat_string, ETH_GSTRING_LEN, "q%u_%.19s",
+					 q, queue_statistics[i].stat_string);
 				memcpy(p, stat_string, ETH_GSTRING_LEN);
 			}
 		}
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 9056f05a67dc..de9e8bad6af2 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -1502,7 +1502,7 @@ static void ff_layout_io_track_ds_error(struct pnfs_layout_segment *lseg,
 {
 	struct nfs4_ff_layout_mirror *mirror;
 	u32 status = *op_status;
-	int err;
+	int err __maybe_unused;
 
 	if (status == 0) {
 		switch (error) {
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
index c2d8a13a9dbd..3fb8dba0abf5 100644
--- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c
+++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
@@ -53,7 +53,8 @@ nfs4_ff_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
 	u32 mp_count;
 	u32 version_count;
 	__be32 *p;
-	int i, ret = -ENOMEM;
+	int i;
+	int ret __maybe_unused = -ENOMEM;
 
 	/* set up xdr stream */
 	scratch = folio_alloc(gfp_flags, 0);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 180229320731..f76c23cdc888 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9241,7 +9241,7 @@ static int _nfs4_proc_create_session(struct nfs_client *clp,
 int nfs4_proc_create_session(struct nfs_client *clp, const struct cred *cred)
 {
 	int status;
-	unsigned *ptr;
+	unsigned *ptr __maybe_unused;
 	struct nfs4_session *session = clp->cl_session;
 	struct nfs4_add_xprt_data xprtdata = {
 		.clp = clp,
-- 
2.34.1