sfc: optional logging of TC offload errors

TC offload support will involve complex limitations on what matches and
 actions a rule can do, in some cases potentially depending on rules
 already offloaded.  So add an ethtool private flag "log-tc-errors" which
 controls reporting the reasons for un-offloadable TC rules at NETIF_INFO.
Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ef100_ethtool.c

@@ -43,6 +43,8 @@ const struct ethtool_ops ef100_ethtool_ops = {
 	.get_pauseparam         = efx_ethtool_get_pauseparam,
 	.set_pauseparam         = efx_ethtool_set_pauseparam,
 	.get_sset_count		= efx_ethtool_get_sset_count,
+	.get_priv_flags		= efx_ethtool_get_priv_flags,
+	.set_priv_flags		= efx_ethtool_set_priv_flags,
 	.self_test		= efx_ethtool_self_test,
 	.get_strings		= efx_ethtool_get_strings,
 	.get_link_ksettings	= efx_ethtool_get_link_ksettings,

drivers/net/ethernet/sfc/ethtool_common.c

@@ -101,6 +101,14 @@ static const struct efx_sw_stat_desc efx_sw_stat_desc[] = {
 
 #define EFX_ETHTOOL_SW_STAT_COUNT ARRAY_SIZE(efx_sw_stat_desc)
 
+static const char efx_ethtool_priv_flags_strings[][ETH_GSTRING_LEN] = {
+	"log-tc-errors",
+};
+
+#define EFX_ETHTOOL_PRIV_FLAGS_LOG_TC_ERRS		BIT(0)
+
+#define EFX_ETHTOOL_PRIV_FLAGS_COUNT ARRAY_SIZE(efx_ethtool_priv_flags_strings)
+
 void efx_ethtool_get_drvinfo(struct net_device *net_dev,
 			     struct ethtool_drvinfo *info)
 {
@@ -452,6 +460,8 @@ int efx_ethtool_get_sset_count(struct net_device *net_dev, int string_set)
 		       efx_ptp_describe_stats(efx, NULL);
 	case ETH_SS_TEST:
 		return efx_ethtool_fill_self_tests(efx, NULL, NULL, NULL);
+	case ETH_SS_PRIV_FLAGS:
+		return EFX_ETHTOOL_PRIV_FLAGS_COUNT;
 	default:
 		return -EINVAL;
 	}
@@ -478,12 +488,39 @@ void efx_ethtool_get_strings(struct net_device *net_dev,
 	case ETH_SS_TEST:
 		efx_ethtool_fill_self_tests(efx, NULL, strings, NULL);
 		break;
+	case ETH_SS_PRIV_FLAGS:
+		for (i = 0; i < EFX_ETHTOOL_PRIV_FLAGS_COUNT; i++)
+			strscpy(strings + i * ETH_GSTRING_LEN,
+				efx_ethtool_priv_flags_strings[i],
+				ETH_GSTRING_LEN);
+		break;
 	default:
 		/* No other string sets */
 		break;
 	}
 }
 
+u32 efx_ethtool_get_priv_flags(struct net_device *net_dev)
+{
+	struct efx_nic *efx = efx_netdev_priv(net_dev);
+	u32 ret_flags = 0;
+
+	if (efx->log_tc_errs)
+		ret_flags |= EFX_ETHTOOL_PRIV_FLAGS_LOG_TC_ERRS;
+
+	return ret_flags;
+}
+
+int efx_ethtool_set_priv_flags(struct net_device *net_dev, u32 flags)
+{
+	struct efx_nic *efx = efx_netdev_priv(net_dev);
+
+	efx->log_tc_errs =
+		!!(flags & EFX_ETHTOOL_PRIV_FLAGS_LOG_TC_ERRS);
+
+	return 0;
+}
+
 void efx_ethtool_get_stats(struct net_device *net_dev,
 			   struct ethtool_stats *stats,
 			   u64 *data)

drivers/net/ethernet/sfc/ethtool_common.h

@@ -27,6 +27,8 @@ int efx_ethtool_fill_self_tests(struct efx_nic *efx,
 int efx_ethtool_get_sset_count(struct net_device *net_dev, int string_set);
 void efx_ethtool_get_strings(struct net_device *net_dev, u32 string_set,
 			     u8 *strings);
+u32 efx_ethtool_get_priv_flags(struct net_device *net_dev);
+int efx_ethtool_set_priv_flags(struct net_device *net_dev, u32 flags);
 void efx_ethtool_get_stats(struct net_device *net_dev,
 			   struct ethtool_stats *stats __attribute__ ((unused)),
 			   u64 *data);

drivers/net/ethernet/sfc/net_driver.h

@@ -855,6 +855,7 @@ enum efx_xdp_tx_queues_mode {
  * @timer_max_ns: Interrupt timer maximum value, in nanoseconds
  * @irq_rx_adaptive: Adaptive IRQ moderation enabled for RX event queues
  * @irqs_hooked: Channel interrupts are hooked
+ * @log_tc_errs: Error logging for TC filter insertion is enabled
  * @irq_rx_mod_step_us: Step size for IRQ moderation for RX event queues
  * @irq_rx_moderation_us: IRQ moderation time for RX event queues
  * @msg_enable: Log message enable flags
@@ -1017,6 +1018,7 @@ struct efx_nic {
 	unsigned int timer_max_ns;
 	bool irq_rx_adaptive;
 	bool irqs_hooked;
+	bool log_tc_errs;
 	unsigned int irq_mod_step_us;
 	unsigned int irq_rx_moderation_us;
 	u32 msg_enable;

drivers/net/ethernet/sfc/tc.h

@@ -14,6 +14,24 @@
 #include <net/flow_offload.h>
 #include "net_driver.h"
 
+/* Error reporting: convenience macros.  For indicating why a given filter
+ * insertion is not supported; errors in internal operation or in the
+ * hardware should be netif_err()s instead.
+ */
+/* Used when error message is constant. */
+#define EFX_TC_ERR_MSG(efx, extack, message)	do {			\
+	NL_SET_ERR_MSG_MOD(extack, message);				\
+	if (efx->log_tc_errs)						\
+		netif_info(efx, drv, efx->net_dev, "%s\n", message);	\
+} while (0)
+/* Used when error message is not constant; caller should also supply a
+ * constant extack message with NL_SET_ERR_MSG_MOD().
+ */
+#define efx_tc_err(efx, fmt, args...)	do {		\
+if (efx->log_tc_errs)					\
+	netif_info(efx, drv, efx->net_dev, fmt, ##args);\
+} while (0)
+
 struct efx_tc_action_set {
 	u16 deliver:1;
 	u32 dest_mport;