Merge branch 'uapi-ethtool-avoid-flex-array-in-struct-ethtool_link_settings'

Kees Cook says:

====================
UAPI: ethtool: Avoid flex-array in struct ethtool_link_settings

This reverts the tagged struct group in struct ethtool_link_settings and
instead just removes the flexible array member from Linux's view as it
is entirely unused.
====================

Link: https://patch.msgid.link/20241115204115.work.686-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -2780,7 +2780,7 @@ u32 bnxt_fw_to_ethtool_speed(u16 fw_link_speed)
 static void bnxt_get_default_speeds(struct ethtool_link_ksettings *lk_ksettings,
 				    struct bnxt_link_info *link_info)
 {
-	struct ethtool_link_settings_hdr *base = &lk_ksettings->base;
+	struct ethtool_link_settings *base = &lk_ksettings->base;
 
 	if (link_info->link_state == BNXT_LINK_STATE_UP) {
 		base->speed = bnxt_fw_to_ethtool_speed(link_info->link_speed);
@@ -2799,7 +2799,7 @@ static void bnxt_get_default_speeds(struct ethtool_link_ksettings *lk_ksettings,
 static int bnxt_get_link_ksettings(struct net_device *dev,
 				   struct ethtool_link_ksettings *lk_ksettings)
 {
-	struct ethtool_link_settings_hdr *base = &lk_ksettings->base;
+	struct ethtool_link_settings *base = &lk_ksettings->base;
 	enum ethtool_link_mode_bit_indices link_mode;
 	struct bnxt *bp = netdev_priv(dev);
 	struct bnxt_link_info *link_info;
@@ -3022,9 +3022,9 @@ u16 bnxt_get_fw_auto_link_speeds(const unsigned long *mode)
 static int bnxt_set_link_ksettings(struct net_device *dev,
 			   const struct ethtool_link_ksettings *lk_ksettings)
 {
-	const struct ethtool_link_settings_hdr *base = &lk_ksettings->base;
 	struct bnxt *bp = netdev_priv(dev);
 	struct bnxt_link_info *link_info = &bp->link_info;
+	const struct ethtool_link_settings *base = &lk_ksettings->base;
 	bool set_pause = false;
 	u32 speed, lanes = 0;
 	int rc = 0;

drivers/net/ethernet/chelsio/cxgb4/cxgb4_ethtool.c

@@ -662,8 +662,8 @@ static unsigned int lmm_to_fw_caps(const unsigned long *link_mode_mask)
 static int get_link_ksettings(struct net_device *dev,
 			      struct ethtool_link_ksettings *link_ksettings)
 {
-	struct ethtool_link_settings_hdr *base = &link_ksettings->base;
 	struct port_info *pi = netdev_priv(dev);
+	struct ethtool_link_settings *base = &link_ksettings->base;
 
 	/* For the nonce, the Firmware doesn't send up Port State changes
 	 * when the Virtual Interface attached to the Port is down.  So
@@ -717,9 +717,9 @@ static int get_link_ksettings(struct net_device *dev,
 static int set_link_ksettings(struct net_device *dev,
 			    const struct ethtool_link_ksettings *link_ksettings)
 {
-	const struct ethtool_link_settings_hdr *base = &link_ksettings->base;
 	struct port_info *pi = netdev_priv(dev);
 	struct link_config *lc = &pi->link_cfg;
+	const struct ethtool_link_settings *base = &link_ksettings->base;
 	struct link_config old_lc;
 	unsigned int fw_caps;
 	int ret = 0;

drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c

@@ -1436,8 +1436,8 @@ static void fw_caps_to_lmm(enum fw_port_type port_type,
 static int cxgb4vf_get_link_ksettings(struct net_device *dev,
 				  struct ethtool_link_ksettings *link_ksettings)
 {
-	struct ethtool_link_settings_hdr *base = &link_ksettings->base;
 	struct port_info *pi = netdev_priv(dev);
+	struct ethtool_link_settings *base = &link_ksettings->base;
 
 	/* For the nonce, the Firmware doesn't send up Port State changes
 	 * when the Virtual Interface attached to the Port is down.  So

drivers/net/ethernet/cisco/enic/enic_ethtool.c

@@ -129,8 +129,8 @@ static void enic_intr_coal_set_rx(struct enic *enic, u32 timer)
 static int enic_get_ksettings(struct net_device *netdev,
 			      struct ethtool_link_ksettings *ecmd)
 {
-	struct ethtool_link_settings_hdr *base = &ecmd->base;
 	struct enic *enic = netdev_priv(netdev);
+	struct ethtool_link_settings *base = &ecmd->base;
 
 	ethtool_link_ksettings_add_link_mode(ecmd, supported,
 					     10000baseT_Full);

drivers/net/ethernet/qlogic/qede/qede_ethtool.c

@@ -504,7 +504,7 @@ static int qede_get_link_ksettings(struct net_device *dev,
 				   struct ethtool_link_ksettings *cmd)
 {
 	typeof(cmd->link_modes) *link_modes = &cmd->link_modes;
-	struct ethtool_link_settings_hdr *base = &cmd->base;
+	struct ethtool_link_settings *base = &cmd->base;
 	struct qede_dev *edev = netdev_priv(dev);
 	struct qed_link_output current_link;
 
@@ -537,7 +537,7 @@ static int qede_get_link_ksettings(struct net_device *dev,
 static int qede_set_link_ksettings(struct net_device *dev,
 				   const struct ethtool_link_ksettings *cmd)
 {
-	const struct ethtool_link_settings_hdr *base = &cmd->base;
+	const struct ethtool_link_settings *base = &cmd->base;
 	const struct ethtool_forced_speed_map *map;
 	struct qede_dev *edev = netdev_priv(dev);
 	struct qed_link_output current_link;

include/linux/ethtool.h

@@ -211,7 +211,7 @@ void ethtool_rxfh_context_lost(struct net_device *dev, u32 context_id);
  * fields, but they are allowed to overwrite them (will be ignored).
  */
 struct ethtool_link_ksettings {
-	struct ethtool_link_settings_hdr base;
+	struct ethtool_link_settings base;
 	struct {
 		__ETHTOOL_DECLARE_LINK_MODE_MASK(supported);
 		__ETHTOOL_DECLARE_LINK_MODE_MASK(advertising);

include/uapi/linux/ethtool.h

@@ -2511,30 +2511,34 @@ enum ethtool_reset_flags {
  *	autonegotiation; 0 if unknown or not applicable.  Read-only.
  */
 struct ethtool_link_settings {
-	/* New members MUST be added within the __struct_group() macro below. */
-	__struct_group(ethtool_link_settings_hdr, hdr, /* no attrs */,
-		__u32	cmd;
-		__u32	speed;
-		__u8	duplex;
-		__u8	port;
-		__u8	phy_address;
-		__u8	autoneg;
-		__u8	mdio_support;
-		__u8	eth_tp_mdix;
-		__u8	eth_tp_mdix_ctrl;
-		__s8	link_mode_masks_nwords;
-		__u8	transceiver;
-		__u8	master_slave_cfg;
-		__u8	master_slave_state;
-		__u8	rate_matching;
-		__u32	reserved[7];
-	);
+	__u32	cmd;
+	__u32	speed;
+	__u8	duplex;
+	__u8	port;
+	__u8	phy_address;
+	__u8	autoneg;
+	__u8	mdio_support;
+	__u8	eth_tp_mdix;
+	__u8	eth_tp_mdix_ctrl;
+	__s8	link_mode_masks_nwords;
+	__u8	transceiver;
+	__u8	master_slave_cfg;
+	__u8	master_slave_state;
+	__u8	rate_matching;
+	__u32	reserved[7];
+#ifndef __KERNEL__
+	/* Linux builds with -Wflex-array-member-not-at-end but does
+	 * not use the "link_mode_masks" member. Leave it defined for
+	 * userspace for now, and when userspace wants to start using
+	 * -Wfamnae, we'll need a new solution.
+	 */
 	__u32	link_mode_masks[];
 	/* layout of link_mode_masks fields:
 	 * __u32 map_supported[link_mode_masks_nwords];
 	 * __u32 map_advertising[link_mode_masks_nwords];
 	 * __u32 map_lp_advertising[link_mode_masks_nwords];
 	 */
+#endif
 };
 
 /**

net/ethtool/ioctl.c

@@ -425,7 +425,7 @@ convert_link_ksettings_to_legacy_settings(
 
 /* layout of the struct passed from/to userland */
 struct ethtool_link_usettings {
-	struct ethtool_link_settings_hdr base;
+	struct ethtool_link_settings base;
 	struct {
 		__u32 supported[__ETHTOOL_LINK_MODE_MASK_NU32];
 		__u32 advertising[__ETHTOOL_LINK_MODE_MASK_NU32];

net/ethtool/linkinfo.c

@@ -8,9 +8,9 @@ struct linkinfo_req_info {
 };
 
 struct linkinfo_reply_data {
-	struct ethnl_reply_data			base;
-	struct ethtool_link_ksettings		ksettings;
-	struct ethtool_link_settings_hdr	*lsettings;
+	struct ethnl_reply_data		base;
+	struct ethtool_link_ksettings	ksettings;
+	struct ethtool_link_settings	*lsettings;
 };
 
 #define LINKINFO_REPDATA(__reply_base) \
@@ -98,7 +98,7 @@ static int
 ethnl_set_linkinfo(struct ethnl_req_info *req_info, struct genl_info *info)
 {
 	struct ethtool_link_ksettings ksettings = {};
-	struct ethtool_link_settings_hdr *lsettings;
+	struct ethtool_link_settings *lsettings;
 	struct net_device *dev = req_info->dev;
 	struct nlattr **tb = info->attrs;
 	bool mod = false;

net/ethtool/linkmodes.c

@@ -11,10 +11,10 @@ struct linkmodes_req_info {
 };
 
 struct linkmodes_reply_data {
-	struct ethnl_reply_data			base;
-	struct ethtool_link_ksettings		ksettings;
-	struct ethtool_link_settings_hdr	*lsettings;
-	bool					peer_empty;
+	struct ethnl_reply_data		base;
+	struct ethtool_link_ksettings	ksettings;
+	struct ethtool_link_settings	*lsettings;
+	bool				peer_empty;
 };
 
 #define LINKMODES_REPDATA(__reply_base) \
@@ -62,12 +62,10 @@ static int linkmodes_reply_size(const struct ethnl_req_info *req_base,
 {
 	const struct linkmodes_reply_data *data = LINKMODES_REPDATA(reply_base);
 	const struct ethtool_link_ksettings *ksettings = &data->ksettings;
+	const struct ethtool_link_settings *lsettings = &ksettings->base;
 	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
-	const struct ethtool_link_settings_hdr *lsettings;
 	int len, ret;
 
-	lsettings = &ksettings->base;
-
 	len = nla_total_size(sizeof(u8)) /* LINKMODES_AUTONEG */
 		+ nla_total_size(sizeof(u32)) /* LINKMODES_SPEED */
 		+ nla_total_size(sizeof(u32)) /* LINKMODES_LANES */
@@ -105,12 +103,10 @@ static int linkmodes_fill_reply(struct sk_buff *skb,
 {
 	const struct linkmodes_reply_data *data = LINKMODES_REPDATA(reply_base);
 	const struct ethtool_link_ksettings *ksettings = &data->ksettings;
+	const struct ethtool_link_settings *lsettings = &ksettings->base;
 	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
-	const struct ethtool_link_settings_hdr *lsettings;
 	int ret;
 
-	lsettings = &ksettings->base;
-
 	if (nla_put_u8(skb, ETHTOOL_A_LINKMODES_AUTONEG, lsettings->autoneg))
 		return -EMSGSIZE;
 
@@ -241,7 +237,7 @@ static int ethnl_update_linkmodes(struct genl_info *info, struct nlattr **tb,
 				  struct ethtool_link_ksettings *ksettings,
 				  bool *mod, const struct net_device *dev)
 {
-	struct ethtool_link_settings_hdr *lsettings = &ksettings->base;
+	struct ethtool_link_settings *lsettings = &ksettings->base;
 	bool req_speed, req_lanes, req_duplex;
 	const struct nlattr *master_slave_cfg, *lanes_cfg;
 	int ret;