gve: introduce config-based allocation for XDP

An earlier patch series[1] introduced RX/TX ring allocation configuration
structs which contained metadata used to allocate and configure new RX
and TX rings. This led to a much cleaner and safer allocation pattern
wherein queue resources were not deallocated until new queue resources
were successfully allocated.

Migrate the XDP allocation path to use the same pattern to allow for the
existence of a single allocation path instead of relying on XDP-specific
allocation methods. These extra allocation methods result in the
duplication of many existing behaviors while being prone to error when
configuration changes unrelated to XDP occur.

Link: https://lore.kernel.org/netdev/[email protected]/ [1]
Reviewed-by: Praveen Kaligineedi <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Signed-off-by: Joshua Washington <[email protected]>
Signed-off-by: Harshitha Ramamurthy <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: josh8551021

drivers/net/ethernet/google/gve/gve.h

@@ -631,10 +631,17 @@ struct gve_notify_block {
 	u32 irq;
 };
 
-/* Tracks allowed and current queue settings */
-struct gve_queue_config {
+/* Tracks allowed and current rx queue settings */
+struct gve_rx_queue_config {
 	u16 max_queues;
-	u16 num_queues; /* current */
+	u16 num_queues;
+};
+
+/* Tracks allowed and current tx queue settings */
+struct gve_tx_queue_config {
+	u16 max_queues;
+	u16 num_queues; /* number of TX queues, excluding XDP queues */
+	u16 num_xdp_queues;
 };
 
 /* Tracks the available and used qpl IDs */
@@ -658,11 +665,11 @@ struct gve_ptype_lut {
 
 /* Parameters for allocating resources for tx queues */
 struct gve_tx_alloc_rings_cfg {
-	struct gve_queue_config *qcfg;
+	struct gve_tx_queue_config *qcfg;
+
+	u16 num_xdp_rings;
 
 	u16 ring_size;
-	u16 start_idx;
-	u16 num_rings;
 	bool raw_addressing;
 
 	/* Allocated resources are returned here */
@@ -672,8 +679,8 @@ struct gve_tx_alloc_rings_cfg {
 /* Parameters for allocating resources for rx queues */
 struct gve_rx_alloc_rings_cfg {
 	/* tx config is also needed to determine QPL ids */
-	struct gve_queue_config *qcfg;
-	struct gve_queue_config *qcfg_tx;
+	struct gve_rx_queue_config *qcfg_rx;
+	struct gve_tx_queue_config *qcfg_tx;
 
 	u16 ring_size;
 	u16 packet_buffer_size;
@@ -764,9 +771,8 @@ struct gve_priv {
 	u32 rx_copybreak; /* copy packets smaller than this */
 	u16 default_num_queues; /* default num queues to set up */
 
-	u16 num_xdp_queues;
-	struct gve_queue_config tx_cfg;
-	struct gve_queue_config rx_cfg;
+	struct gve_tx_queue_config tx_cfg;
+	struct gve_rx_queue_config rx_cfg;
 	u32 num_ntfy_blks; /* spilt between TX and RX so must be even */
 
 	struct gve_registers __iomem *reg_bar0; /* see gve_register.h */
@@ -1039,27 +1045,16 @@ static inline bool gve_is_qpl(struct gve_priv *priv)
 }
 
 /* Returns the number of tx queue page lists */
-static inline u32 gve_num_tx_qpls(const struct gve_queue_config *tx_cfg,
-				  int num_xdp_queues,
+static inline u32 gve_num_tx_qpls(const struct gve_tx_queue_config *tx_cfg,
 				  bool is_qpl)
 {
 	if (!is_qpl)
 		return 0;
-	return tx_cfg->num_queues + num_xdp_queues;
-}
-
-/* Returns the number of XDP tx queue page lists
- */
-static inline u32 gve_num_xdp_qpls(struct gve_priv *priv)
-{
-	if (priv->queue_format != GVE_GQI_QPL_FORMAT)
-		return 0;
-
-	return priv->num_xdp_queues;
+	return tx_cfg->num_queues + tx_cfg->num_xdp_queues;
 }
 
 /* Returns the number of rx queue page lists */
-static inline u32 gve_num_rx_qpls(const struct gve_queue_config *rx_cfg,
+static inline u32 gve_num_rx_qpls(const struct gve_rx_queue_config *rx_cfg,
 				  bool is_qpl)
 {
 	if (!is_qpl)
@@ -1077,7 +1072,8 @@ static inline u32 gve_rx_qpl_id(struct gve_priv *priv, int rx_qid)
 	return priv->tx_cfg.max_queues + rx_qid;
 }
 
-static inline u32 gve_get_rx_qpl_id(const struct gve_queue_config *tx_cfg, int rx_qid)
+static inline u32 gve_get_rx_qpl_id(const struct gve_tx_queue_config *tx_cfg,
+				    int rx_qid)
 {
 	return tx_cfg->max_queues + rx_qid;
 }
@@ -1087,7 +1083,7 @@ static inline u32 gve_tx_start_qpl_id(struct gve_priv *priv)
 	return gve_tx_qpl_id(priv, 0);
 }
 
-static inline u32 gve_rx_start_qpl_id(const struct gve_queue_config *tx_cfg)
+static inline u32 gve_rx_start_qpl_id(const struct gve_tx_queue_config *tx_cfg)
 {
 	return gve_get_rx_qpl_id(tx_cfg, 0);
 }
@@ -1118,7 +1114,7 @@ static inline bool gve_is_gqi(struct gve_priv *priv)
 
 static inline u32 gve_num_tx_queues(struct gve_priv *priv)
 {
-	return priv->tx_cfg.num_queues + priv->num_xdp_queues;
+	return priv->tx_cfg.num_queues + priv->tx_cfg.num_xdp_queues;
 }
 
 static inline u32 gve_xdp_tx_queue_id(struct gve_priv *priv, u32 queue_id)
@@ -1234,8 +1230,8 @@ int gve_adjust_config(struct gve_priv *priv,
 		      struct gve_tx_alloc_rings_cfg *tx_alloc_cfg,
 		      struct gve_rx_alloc_rings_cfg *rx_alloc_cfg);
 int gve_adjust_queues(struct gve_priv *priv,
-		      struct gve_queue_config new_rx_config,
-		      struct gve_queue_config new_tx_config,
+		      struct gve_rx_queue_config new_rx_config,
+		      struct gve_tx_queue_config new_tx_config,
 		      bool reset_rss);
 /* flow steering rule */
 int gve_get_flow_rule_entry(struct gve_priv *priv, struct ethtool_rxnfc *cmd);

drivers/net/ethernet/google/gve/gve_ethtool.c

@@ -475,8 +475,8 @@ static int gve_set_channels(struct net_device *netdev,
 			    struct ethtool_channels *cmd)
 {
 	struct gve_priv *priv = netdev_priv(netdev);
-	struct gve_queue_config new_tx_cfg = priv->tx_cfg;
-	struct gve_queue_config new_rx_cfg = priv->rx_cfg;
+	struct gve_tx_queue_config new_tx_cfg = priv->tx_cfg;
+	struct gve_rx_queue_config new_rx_cfg = priv->rx_cfg;
 	struct ethtool_channels old_settings;
 	int new_tx = cmd->tx_count;
 	int new_rx = cmd->rx_count;
@@ -491,10 +491,17 @@ static int gve_set_channels(struct net_device *netdev,
 	if (!new_rx || !new_tx)
 		return -EINVAL;
 
-	if (priv->num_xdp_queues &&
-	    (new_tx != new_rx || (2 * new_tx > priv->tx_cfg.max_queues))) {
-		dev_err(&priv->pdev->dev, "XDP load failed: The number of configured RX queues should be equal to the number of configured TX queues and the number of configured RX/TX queues should be less than or equal to half the maximum number of RX/TX queues");
-		return -EINVAL;
+	if (priv->xdp_prog) {
+		if (new_tx != new_rx ||
+		    (2 * new_tx > priv->tx_cfg.max_queues)) {
+			dev_err(&priv->pdev->dev, "The number of configured RX queues should be equal to the number of configured TX queues and the number of configured RX/TX queues should be less than or equal to half the maximum number of RX/TX queues when XDP program is installed");
+			return -EINVAL;
+		}
+
+		/* One XDP TX queue per RX queue. */
+		new_tx_cfg.num_xdp_queues = new_rx;
+	} else {
+		new_tx_cfg.num_xdp_queues = 0;
 	}
 
 	if (new_rx != priv->rx_cfg.num_queues &&