idpf_size_to_txd_count(9)

💅 idpf_size_to_txd_count — the Kernel API Manual, bestie edition ✨

Okay so real talk, this one's a tiny little helper living in the kernel API manual (that's the (9) part, iykyk), and it's literally just here to do math for you. Let's get into it 🫶

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✨ NAME ✨

idpf_size_to_txd_count — get the number of descriptors you need for a large Tx frag 🎀

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🌸 SYNOPSIS 🌸

u32 idpf_size_to_txd_count (unsigned int size );

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🦋 ARGUMENTS 🦋

• size — the transmit request size, in bytes. that's it. that's the whole input 💖

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💜 DESCRIPTION 💜

So here's the vibe: when you've got a large frag on your hands — and by large we mean >= 16K — it has to get split across multiple descriptors. No cap, one descriptor can't hold it all.

Because of that, the function has to assume the worst case: no more than 12K of data per descriptor. Why so stingy? Hardware alignment restrictions, babes — specifically 4K alignment 🔥

So yeah, it's giving "how many descriptors do I need" energy, and it's doing the math with that 12K-per-descriptor assumption baked in. Iconic, honestly.

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👑 SEE ALSO 👑

Kernel file ./drivers/net/ethernet/intel/idpf/idpf_txrx.h, plus the whole friend group:

• struct idpf_tx_offload_params(9)
• struct idpf_tx_splitq_params(9)
• enum idpf_queue_flags_t(9)
• struct idpf_vec_regs(9)
• struct idpf_intr_reg(9)
• struct idpf_q_vector(9)
• struct idpf_rx_queue(9)
• struct idpf_tx_queue(9)
• struct idpf_buf_queue(9)
• struct idpf_compl_queue(9)
• struct idpf_sw_queue(9)
• struct idpf_rxq_set(9)
• struct idpf_bufq_set(9)
• struct idpf_rxq_group(9)
• struct idpf_txq_group(9)
• idpf_tx_singleq_build_ctob(9)
• idpf_tx_splitq_build_desc(9)
• idpf_vport_intr_set_wb_on_itr(9)
• idpf_tx_splitq_get_free_bufs(9)

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And that's the whole page, bestie!! 🌈 Sourced straight from ./drivers/net/ethernet/intel/idpf, dated October 2026 — mwah, go forth and count your descriptors 💅💖