[PATCH net-next 2/2] gve: Use ethtool_sprintf/puts() to fill stats strings

Simon Horman
2024-05-03T20:31:42Z

Make use of standard helpers to simplify filling in stats strings.

The first two ethtool_puts() changes address the following fortification
warnings flagged by W=1 builds with clang-18. (The last ethtool_puts
change does not because the warning relates to writing beyond the first
element of an array, and gve_gstrings_priv_flags only has one element.)

.../fortify-string.h:562:4: warning: call to '__read_overflow2_field' declared with 'warning' attribute: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Wattribute-warning]
562 | __read_overflow2_field(q_size_field, size);
| ^
.../fortify-string.h:562:4: warning: call to '__read_overflow2_field' declared with 'warning' attribute: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Wattribute-warning]

Likewise, the same changes resolve the same problems flagged by Smatch.

.../gve_ethtool.c:100 gve_get_strings() error: __builtin_memcpy() '*gve_gstrings_main_stats' too small (32 vs 576)
.../gve_ethtool.c:120 gve_get_strings() error: __builtin_memcpy() '*gve_gstrings_adminq_stats' too small (32 vs 512)

Compile tested only.

Signed-off-by: Simon Horman <horms@kernel.org>
---
drivers/net/ethernet/google/gve/gve_ethtool.c | 42 +++++++++++----------------
1 file changed, 17 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
index bd7632eed776..31563eeb0a41 100644
--- a/drivers/net/ethernet/google/gve/gve_ethtool.c
+++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
@@ -89,42 +89,34 @@ static const char gve_gstrings_priv_flags[][ETH_GSTRING_LEN] = {
static void gve_get_strings(struct net_device *netdev, u32 stringset, u8 *data)
{
struct gve_priv *priv = netdev_priv(netdev);
- char *s = (char *)data;
+ u8 *s = (char *)data;
int num_tx_queues;
int i, j;

num_tx_queues = gve_num_tx_queues(priv);
switch (stringset) {
case ETH_SS_STATS:
- memcpy(s, *gve_gstrings_main_stats,
- sizeof(gve_gstrings_main_stats));
- s += sizeof(gve_gstrings_main_stats);
-
- for (i = 0; i < priv->rx_cfg.num_queues; i++) {
- for (j = 0; j < NUM_GVE_RX_CNTS; j++) {
- snprintf(s, ETH_GSTRING_LEN,
- gve_gstrings_rx_stats[j], i);
- s += ETH_GSTRING_LEN;
- }
- }
+ for (i = 0; i < ARRAY_SIZE(gve_gstrings_main_stats); i++)
+ ethtool_puts(&s, gve_gstrings_main_stats[i]);

- for (i = 0; i < num_tx_queues; i++) {
- for (j = 0; j < NUM_GVE_TX_CNTS; j++) {
- snprintf(s, ETH_GSTRING_LEN,
- gve_gstrings_tx_stats[j], i);
- s += ETH_GSTRING_LEN;
- }
- }
+ for (i = 0; i < priv->rx_cfg.num_queues; i++)
+ for (j = 0; j < NUM_GVE_RX_CNTS; j++)
+ ethtool_sprintf(&s, gve_gstrings_rx_stats[j],
+ i);
+
+ for (i = 0; i < num_tx_queues; i++)
+ for (j = 0; j < NUM_GVE_TX_CNTS; j++)
+ ethtool_sprintf(&s, gve_gstrings_tx_stats[j],
+ i);
+
+ for (i = 0; i < ARRAY_SIZE(gve_gstrings_adminq_stats); i++)
+ ethtool_puts(&s, gve_gstrings_adminq_stats[i]);

- memcpy(s, *gve_gstrings_adminq_stats,
- sizeof(gve_gstrings_adminq_stats));
- s += sizeof(gve_gstrings_adminq_stats);
break;

case ETH_SS_PRIV_FLAGS:
- memcpy(s, *gve_gstrings_priv_flags,
- sizeof(gve_gstrings_priv_flags));
- s += sizeof(gve_gstrings_priv_flags);
+ for (i = 0; i < ARRAY_SIZE(gve_gstrings_priv_flags); i++)
+ ethtool_puts(&s, gve_gstrings_priv_flags[i]);
break;

default:

--
2.43.0