ethtool_mm_...e_min_to_add(9)

💅 ethtool_mm_frag_size_min_to_add(9) ✨

okay so bestie, welcome to the Kernel API Manual 🎀 — yes, the actual kernel API manual, we're reading it together, it's giving study date energy 📚💖. This one's about turning a minimum fragment size in octets into the standard additional fragment size multiplier, which sounds scary but it's literally just math with a glow-up. stay with me 🫶

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✨ NAME ✨

ethtool_mm_frag_size_min_to_add — translate a minimum fragment size expressed in octets (the absolute version) into the standard additional fragment size expressed as a multiplier. lowkey a unit conversion but make it networking 💅

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🌸 SYNOPSIS 🌸

int ethtool_mm_frag_size_min_to_add (u32 val_min , u32 *val_add , struct netlink_ext_ack *extack );

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🦋 ARGUMENTS 🦋

• val_min — the value of the addFragSize variable, but in octets 🍓 (yes, this is the absolute one, the one in bytes, not the multiplier — keep up bestie).
• val_add — a pointer to where the standard addFragSize value gets returned 🎀 so the function can hand you back the multiplier through this.
• extack — the netlink extended ack 💌 (the little messenger that carries the details when things go sideways).

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👑 DESCRIPTION 👑

So what this does, fr fr: it takes a value in octets and translates it into one of 0, 1, 2, 3 💀 — using the reverse application of the 802.3 formula:

64 * (1 + addFragSize) - 4

Like, you run that formula backwards and out pops the multiplier. iconic behavior honestly ✨.

🫶 who calls this? Drivers which do not support programming the minimum fragment size to a continuous range. if your driver can do the continuous thing, this ain't for you bestie.

And if you hand it some other fragment length value? It returns an error 🙈 — no guessing, no vibes-based fallback, just nope. periodt.

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🌈 SEE ALSO 🌈

Kernel file ./include/linux/ethtool.h, plus the whole friend group 👯‍♀️ — go say hi:

• enum ethtool_phys_id_state(9)
• struct kernel_ethtool_ringparam(9)
• enum ethtool_supported_ring_param(9)
• ethtool_rxfh_indir_default(9)
• struct ethtool_rxfh_context(9)
• ethtool_link_ksettings_zero_link_mode(9)
• ethtool_link_ksettings_add_link_mode(9)
• ethtool_link_ksettings_del_link_mode(9)
• ethtool_link_ksettings_test_link_mode(9)
• ethtool_intersect_link_masks(9)
• struct ethtool_phy_stats(9)
• struct ethtool_pause_stats(9)
• struct ethtool_fec_hist_range(9)
• struct ethtool_fec_stats(9)
• struct ethtool_rmon_hist_range(9)
• struct ethtool_rmon_stats(9)
• struct ethtool_ts_stats(9)
• struct ethtool_module_eeprom(9)
• struct ethtool_module_power_mode_params(9)
• struct ethtool_mm_state(9)
• struct ethtool_mm_cfg(9)
• struct ethtool_mm_stats(9)
• struct ethtool_mmsv_ops(9)
• struct ethtool_mmsv(9)
• struct ethtool_rxfh_param(9)
• struct ethtool_rxfh_fields(9)
• struct kernel_ethtool_ts_info(9)
• struct ethtool_ops(9)
• struct ethtool_netdev_state(9)
• struct ethtool_phy_ops(9)
• ethtool_set_ethtool_phy_ops(9)
• ethtool_params_from_link_mode(9)
• ethtool_get_phc_vclocks(9)
• ethtool_mm_frag_size_add_to_min(9) ← the other direction, the remix 🎧
• ethtool_get_ts_info_by_layer(9)
• ethtool_sprintf(9)
• ethtool_puts(9)
• ethtool_cpy(9)

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💜 mwah, that's the whole page. this lil masterpiece lives in ./include/linux, stamped October 2026, from the Kernel API Manual — go off, kernel docs, you ate. 💅✨🎀