ethtool: add two coalesce attributes for CQE mode

Currently, there are many drivers who support CQE mode configuration,
some configure it as a fixed when initialized, some provide an
interface to change it by ethtool private flags. In order to make it
more generic, add two new 'ETHTOOL_A_COALESCE_USE_CQE_TX' and
'ETHTOOL_A_COALESCE_USE_CQE_RX' coalesce attributes, then these
parameters can be accessed by ethtool netlink coalesce uAPI.

Also add an new structure kernel_ethtool_coalesce, then the
new parameter can be added into this struct.

Signed-off-by: Yufeng Mo <[e-mail]>
Signed-off-by: Huazhong Tan <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/networking/ethtool-netlink.rst

···
   ``ETHTOOL_A_COALESCE_TX_USECS_HIGH``         u32     delay (us), high Tx
   ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH``    u32     max packets, high Tx
   ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL``  u32     rate sampling interval
+  ``ETHTOOL_A_COALESCE_USE_CQE_TX``            bool    timer reset mode, Tx
+  ``ETHTOOL_A_COALESCE_USE_CQE_RX``            bool    timer reset mode, Rx
   ===========================================  ======  =======================
 
 Attributes are only included in reply if their value is not zero or the
 corresponding bit in ``ethtool_ops::supported_coalesce_params`` is set (i.e.
 they are declared as supported by driver).
 
+Timer reset mode (``ETHTOOL_A_COALESCE_USE_CQE_TX`` and
+``ETHTOOL_A_COALESCE_USE_CQE_RX``) controls the interaction between packet
+arrival and the various time based delay parameters. By default timers are
+expected to limit the max delay between any packet arrival/departure and a
+corresponding interrupt. In this mode timer should be started by packet
+arrival (sometimes delivery of previous interrupt) and reset when interrupt
+is delivered.
+Setting the appropriate attribute to 1 will enable ``CQE`` mode, where
+each packet event resets the timer. In this mode timer is used to force
+the interrupt if queue goes idle, while busy queues depend on the packet
+limit to trigger interrupts.
 
 COALESCE_SET
 ============
···
   ``ETHTOOL_A_COALESCE_TX_USECS_HIGH``         u32     delay (us), high Tx
   ``ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH``    u32     max packets, high Tx
   ``ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL``  u32     rate sampling interval
+  ``ETHTOOL_A_COALESCE_USE_CQE_TX``            bool    timer reset mode, Tx
+  ``ETHTOOL_A_COALESCE_USE_CQE_RX``            bool    timer reset mode, Rx
   ===========================================  ======  =======================
 
 Request is rejected if it attributes declared as unsupported by driver (i.e.

include/linux/ethtool.h

···
 __ethtool_get_link_ksettings(struct net_device *dev,
 			     struct ethtool_link_ksettings *link_ksettings);
 
+struct kernel_ethtool_coalesce {
+	u8 use_cqe_mode_tx;
+	u8 use_cqe_mode_rx;
+};
+
 /**
  * ethtool_intersect_link_masks - Given two link masks, AND them together
  * @dst: first mask and where result is stored
···
 #define ETHTOOL_COALESCE_TX_USECS_HIGH		BIT(19)
 #define ETHTOOL_COALESCE_TX_MAX_FRAMES_HIGH	BIT(20)
 #define ETHTOOL_COALESCE_RATE_SAMPLE_INTERVAL	BIT(21)
-#define ETHTOOL_COALESCE_ALL_PARAMS		GENMASK(21, 0)
+#define ETHTOOL_COALESCE_USE_CQE_RX		BIT(22)
+#define ETHTOOL_COALESCE_USE_CQE_TX		BIT(23)
+#define ETHTOOL_COALESCE_ALL_PARAMS		GENMASK(23, 0)
 
 #define ETHTOOL_COALESCE_USECS						\
 	(ETHTOOL_COALESCE_RX_USECS | ETHTOOL_COALESCE_TX_USECS)
···
 	 ETHTOOL_COALESCE_RX_USECS_LOW | ETHTOOL_COALESCE_RX_USECS_HIGH | \
 	 ETHTOOL_COALESCE_PKT_RATE_LOW | ETHTOOL_COALESCE_PKT_RATE_HIGH | \
 	 ETHTOOL_COALESCE_RATE_SAMPLE_INTERVAL)
+#define ETHTOOL_COALESCE_USE_CQE					\
+	(ETHTOOL_COALESCE_USE_CQE_RX | ETHTOOL_COALESCE_USE_CQE_TX)
 
 #define ETHTOOL_STAT_NOT_SET	(~0ULL)
 

include/uapi/linux/ethtool_netlink.h

···
 	ETHTOOL_A_COALESCE_TX_USECS_HIGH,		/* u32 */
 	ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH,		/* u32 */
 	ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL,	/* u32 */
+	ETHTOOL_A_COALESCE_USE_CQE_MODE_TX,		/* u8 */
+	ETHTOOL_A_COALESCE_USE_CQE_MODE_RX,		/* u8 */
 
 	/* add new constants above here */
 	__ETHTOOL_A_COALESCE_CNT,

net/ethtool/coalesce.c

···
 struct coalesce_reply_data {
 	struct ethnl_reply_data		base;
 	struct ethtool_coalesce		coalesce;
+	struct kernel_ethtool_coalesce	kernel_coalesce;
 	u32				supported_params;
 };
 
···
 	       nla_total_size(sizeof(u32)) +	/* _RX_MAX_FRAMES_HIGH */
 	       nla_total_size(sizeof(u32)) +	/* _TX_USECS_HIGH */
 	       nla_total_size(sizeof(u32)) +	/* _TX_MAX_FRAMES_HIGH */
-	       nla_total_size(sizeof(u32));	/* _RATE_SAMPLE_INTERVAL */
+	       nla_total_size(sizeof(u32)) +	/* _RATE_SAMPLE_INTERVAL */
+	       nla_total_size(sizeof(u8)) +	/* _USE_CQE_MODE_TX */
+	       nla_total_size(sizeof(u8));	/* _USE_CQE_MODE_RX */
 }
 
 static bool coalesce_put_u32(struct sk_buff *skb, u16 attr_type, u32 val,
···
 			       const struct ethnl_reply_data *reply_base)
 {
 	const struct coalesce_reply_data *data = COALESCE_REPDATA(reply_base);
+	const struct kernel_ethtool_coalesce *kcoal = &data->kernel_coalesce;
 	const struct ethtool_coalesce *coal = &data->coalesce;
 	u32 supported = data->supported_params;
 
···
 	    coalesce_put_u32(skb, ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH,
 			     coal->tx_max_coalesced_frames_high, supported) ||
 	    coalesce_put_u32(skb, ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL,
-			     coal->rate_sample_interval, supported))
+			     coal->rate_sample_interval, supported) ||
+	    coalesce_put_bool(skb, ETHTOOL_A_COALESCE_USE_CQE_MODE_TX,
+			      kcoal->use_cqe_mode_tx, supported) ||
+	    coalesce_put_bool(skb, ETHTOOL_A_COALESCE_USE_CQE_MODE_RX,
+			      kcoal->use_cqe_mode_rx, supported))
 		return -EMSGSIZE;
 
 	return 0;
···
 	[ETHTOOL_A_COALESCE_TX_USECS_HIGH]	= { .type = NLA_U32 },
 	[ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH]	= { .type = NLA_U32 },
 	[ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL] = { .type = NLA_U32 },
+	[ETHTOOL_A_COALESCE_USE_CQE_MODE_TX]	= NLA_POLICY_MAX(NLA_U8, 1),
+	[ETHTOOL_A_COALESCE_USE_CQE_MODE_RX]	= NLA_POLICY_MAX(NLA_U8, 1),
 };
 
 int ethnl_set_coalesce(struct sk_buff *skb, struct genl_info *info)
 {
+	struct kernel_ethtool_coalesce kernel_coalesce = {};
 	struct ethtool_coalesce coalesce = {};
 	struct ethnl_req_info req_info = {};
 	struct nlattr **tb = info->attrs;
···
 			 tb[ETHTOOL_A_COALESCE_TX_MAX_FRAMES_HIGH], &mod);
 	ethnl_update_u32(&coalesce.rate_sample_interval,
 			 tb[ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL], &mod);
+	ethnl_update_u8(&kernel_coalesce.use_cqe_mode_tx,
+			tb[ETHTOOL_A_COALESCE_USE_CQE_MODE_TX], &mod);
+	ethnl_update_u8(&kernel_coalesce.use_cqe_mode_rx,
+			tb[ETHTOOL_A_COALESCE_USE_CQE_MODE_RX], &mod);
 	ret = 0;
 	if (!mod)
 		goto out_ops;

net/ethtool/netlink.h

···
 extern const struct nla_policy ethnl_channels_get_policy[ETHTOOL_A_CHANNELS_HEADER + 1];
 extern const struct nla_policy ethnl_channels_set_policy[ETHTOOL_A_CHANNELS_COMBINED_COUNT + 1];
 extern const struct nla_policy ethnl_coalesce_get_policy[ETHTOOL_A_COALESCE_HEADER + 1];
-extern const struct nla_policy ethnl_coalesce_set_policy[ETHTOOL_A_COALESCE_RATE_SAMPLE_INTERVAL + 1];
+extern const struct nla_policy ethnl_coalesce_set_policy[ETHTOOL_A_COALESCE_MAX + 1];
 extern const struct nla_policy ethnl_pause_get_policy[ETHTOOL_A_PAUSE_HEADER + 1];
 extern const struct nla_policy ethnl_pause_set_policy[ETHTOOL_A_PAUSE_TX + 1];
 extern const struct nla_policy ethnl_eee_get_policy[ETHTOOL_A_EEE_HEADER + 1];