alloc_ltb_set(9)

💅 alloc_ltb_set — NAME

okay so bestie, welcome to the Kernel API Manual entry for alloc_ltb_set — a.k.a. the function that goes and allocates a set of long term buffers, which we're gonna call LTBs from here on out because life is short and so is that acronym. ✨

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🌸 SYNOPSIS

int alloc_ltb_set (struct ibmvnic_adapter *adapter , struct
ibmvnic_ltb_set *ltb_set , int num_buffs , int buff_size );

that's the whole vibe: returns an int, takes four things, and honestly? it's giving "small function, big responsibility". 🫶

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🎀 ARGUMENTS

• adapter — the ibmvnic adapter that's associated with the LTB. like, whose LTB is this? this one's. 💖
• ltb_set — the container object for the set of LTBs. think of it as the cute little bag that holds all the buffers. 🎀
• num_buffs — how many buffers are in the LTB. literally the count. that's it. that's the number.
• buff_size — the size of each buffer in the LTB. every single one of them. no cap. ⭐

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🦋 DESCRIPTION

okay so here's what's actually happening — alloc_ltb_set allocates a set of LTBs so the system can accommodate num_buffs buffers of buff_size each. 💅

and rn? we cap the size of each LTB to IBMVNIC_ONE_LTB_SIZE. that's the ceiling, bestie, nobody's going above it. 🔥

now for the clever part, because this function is genuinely an icon:

• if the new set of LTBs has fewer LTBs than the old set, it frees the excess LTBs — bye, don't need you anymore 👋
• if the new set needs more than the old set, it allocates the remaining ones — making room, we love to see it 🌈

and the whole strategy is: try and reuse as many LTBs as possible and avoid reallocation. like, why re-allocate when you can recycle? environmentally conscious queen behavior honestly. ♻️✨

⚠️ okay but for real, important warning time: any changes to this allocation strategy must be reflected in map_rxpool_buff_to_ltb and map_txpool_buff_to_ltb. if you change this and forget those two, that's not slay, that's a bug. don't do that to me. 😭

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👑 SEE ALSO

the whole friend group, assembled:

• Kernel file ./drivers/net/ethernet/ibm/ibmvnic.c — the source, the origin, the mothership 💜
• ibmvnic_wait_for_completion(9)
• reuse_ltb(9)
• alloc_long_term_buff(9)
• free_ltb_set(9)
• map_rxpool_buf_to_ltb(9)
• map_txpool_buf_to_ltb(9)
• release_rx_pools(9)
• reuse_rx_pools(9)
• init_rx_pools(9)
• release_tx_pools(9)
• reuse_tx_pools(9)
• init_tx_pools(9)
• get_hdr_lens(9)
• create_hdr_descs(9)
• build_hdr_descs_arr(9)
• do_passive_init(9)

okay that's seventeen cross-references, i counted, you're welcome. iykyk. 💀

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🧚 sign-off

and that's the whole page, bestie!! 🍓 this iconic little writeup lives at ./drivers/net/ethernet/ibm, and it's dated October 2026 — so mark your calendar, screenshot it, send it to the group chat, whatever you gotta do. alloc_ltb_set(9) said periodt. 💅✨👑