[PATCH] net: macb: use ethtool_sprintf to fill ethtool stats strings

[Sean Chang]

The RISC-V toolchain triggers a stringop-truncation warning when using
snprintf() with a fixed ETH_GSTRING_LEN (32 bytes) buffer.

Convert the driver to use the modern ethtool_sprintf() API from
linux/ethtool.h. This removes the need for manual snprintf() and
memcpy() calls, handles the 32-byte padding automatically, and
simplifies the logic by removing manual pointer arithmetic.

Suggested-by: Andrew Lunn <andrew@xxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Signed-off-by: Sean Chang <seanwascoding@xxxxxxxxx>
---
his patch was previously part of a SUNRPC/NFSD series [1], but is now
sent as a standalone cleanup as suggested by Andy Shevchenko to avoid
cross-subsystem dependencies.

[1] https://lore.kernel.org/all/20260301161709.1365975-1-seanwascoding@xxxxxxxxx/

 drivers/net/ethernet/cadence/macb_main.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 5bc35f651ebd..dadfedd6d799 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -3145,7 +3145,6 @@ static int gem_get_sset_count(struct net_device *dev, int sset)
 
 static void gem_get_ethtool_strings(struct net_device *dev, u32 sset, u8 *p)
 {
-	char stat_string[ETH_GSTRING_LEN];
 	struct macb *bp = netdev_priv(dev);
 	struct macb_queue *queue;
 	unsigned int i;
@@ -3158,11 +3157,8 @@ static void gem_get_ethtool_strings(struct net_device *dev, u32 sset, u8 *p)
 			       ETH_GSTRING_LEN);
 
 		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);
-				memcpy(p, stat_string, ETH_GSTRING_LEN);
-			}
+			for (i = 0; i < QUEUE_STATS_LEN; i++)
+				ethtool_sprintf(&p, "q%u_%s", q, queue_statistics[i].stat_string);
 		}
 		break;
 	}
-- 
2.34.1