mlx5_lag_shared_fdb_create(9)

💅 mlx5_lag_shared_fdb_create — Kernel API Manual ✨

okay bestie, buckle up, because we're diving into mlx5_lag_shared_fdb_create(9) from the Kernel API Manual and honestly? it's giving kernel-internals realness 🦋 this one lives in the mlx5 core driver and it's all about making a shared FDB LAG happen. no cap.

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🎀 NAME 🎀

mlx5_lag_shared_fdb_create — Create shared FDB LAG 💖 literally what it says on the tin, she creates the shared FDB LAG, periodt.

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✨ SYNOPSIS ✨

int mlx5_lag_shared_fdb_create (struct mlx5_lag *ldev , struct
       lag_tracker *tracker , enum mlx5_lag_mode mode , u32 group_id );

four args, one int back, that's the whole vibe 🌸

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🫶 ARGUMENTS 🫶

so here's the cast of characters, and every single one matters:

• ldev — the LAG device itself 👑 main character energy, she's a struct mlx5_lag *.
• tracker — the LAG tracker 🧚 a struct lag_tracker *. and heads up: it's NULL for SD. yes, literally NULL, don't come for me.
• mode — the LAG mode 🌈 an enum mlx5_lag_mode. plot twist: it's unused for SD. lowkey just vibing there.
• group_id — the SD group ID 🔥 a u32, and this one's got lore:
  • 0 (MLX5_LAG_FILTER_PORTS) means ports LAG
  • MLX5_LAG_FILTER_ALL means all-device (mpesw) LAG
  • or it's a specific SD group ID — see the description below, iykyk

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💀 DESCRIPTION 💀

okay so this is where it gets good. the behaviour of this function depends entirely on what you pass as group_id, and there are two whole situations:

• when group_id is 0 (MLX5_LAG_FILTER_PORTS) or MLX5_LAG_FILTER_ALL → it activates a FW LAG with shared FDB ⚡ firmware's getting involved, it's a whole moment.
• when group_id is a specific SD group ID → it creates a software-only shared FDB scoped to that group, and no FW LAG commands happen at all 🙈 software-only, staying in her lane, no firmware drama.

so yeah: same function, two completely different energies depending on group_id. vibe check accordingly 💅

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⭐ RETURN ⭐

• 0 on success 🎉 slay, she worked.
• negative error code on failure 😭 it's giving "something went wrong," and that's genuinely all the detail we have, bestie — a negative error code, no cap.

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/net/ethernet/mellanox/mlx5/core/lag/shared_fdb.c — go read the source if you want the full lore 👑

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ngl, if you're poking at LAG modes and group IDs in the mlx5 driver, you probably already know what you're doing. but if you didn't before? now you do 💜

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and that's the page, bestie 🎀 source path was ./drivers/net/ethernet/mellano... and the date stamp on this whole thing is October 2026 ⭐ she's from the future, iconic 💅🦋

mlx5_lag_shared_fdb_create(9) — mwah, no notes 💖