net: pass net_device_path_ctx to dev_fill_forward_path()

Refactor dev_fill_forward_path() to take a struct net_device_path_ctx
pointer instead of a (dev, daddr) pair, so the caller can build and
populate the context up front and keep it after the forward path walk.

This allows additional fields (e.g. vlan and ether_type) to be carried
in the context and shared with ndo_fill_forward_path implementations,
instead of being reconstructed on the stack inside the core helper.

Update the mtk_ppe_offload, airoha_ppe and nf_flow_table_path callers to
allocate and fill the context before invoking dev_fill_forward_path().
The network topology resolution behaviour is unchanged.

This is a preliminary patch to enable HW flowtable offload for IPv4
over IPv6 tunnels.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 7 insertions, 11 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index fd0b445f5d38..1755dd0b2a92 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -769,35 +769,31 @@ void dev_fill_forward_path_release(struct net_device_path_stack *stack)
 }
 EXPORT_SYMBOL_GPL(dev_fill_forward_path_release);
 
-int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
+int dev_fill_forward_path(struct net_device_path_ctx *ctx,
 			  struct net_device_path_stack *stack)
 {
 	const struct net_device *last_dev;
-	struct net_device_path_ctx ctx = {
-		.dev	= dev,
-	};
 	struct net_device_path *path;
 	int ret = 0;
 
-	memcpy(ctx.daddr, daddr, sizeof(ctx.daddr));
 	stack->num_paths = 0;
-	while (ctx.dev && ctx.dev->netdev_ops->ndo_fill_forward_path) {
-		last_dev = ctx.dev;
+	while (ctx->dev && ctx->dev->netdev_ops->ndo_fill_forward_path) {
+		last_dev = ctx->dev;
 		path = dev_fwd_path(stack);
 		if (!path)
 			goto err_out;
 
 		memset(path, 0, sizeof(struct net_device_path));
-		ret = ctx.dev->netdev_ops->ndo_fill_forward_path(&ctx, path);
+		ret = ctx->dev->netdev_ops->ndo_fill_forward_path(ctx, path);
 		if (ret < 0)
 			goto err_out;
 
 		stack->num_paths++;
-		if (WARN_ON_ONCE(last_dev == ctx.dev))
+		if (WARN_ON_ONCE(last_dev == ctx->dev))
 			goto err_out;
 	}
 
-	if (!ctx.dev)
+	if (!ctx->dev)
 		return ret;
 
 	path = dev_fwd_path(stack);
@@ -805,7 +801,7 @@ int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
 		goto err_out;
 
 	path->type = DEV_PATH_ETHERNET;
-	path->dev = ctx.dev;
+	path->dev = ctx->dev;
 	stack->num_paths++;
 
 	return 0;