arm_mbo_chain(9)

💅 arm_mbo_chain — the Kernel API Manual, but make it cute

okay so bestie, today we're learning about arm_mbo_chain, a helper function that arms an MBO chain for the HDM. yes that's a lot of acronyms and no i will not be explaining them all, just trust the process 🫶

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✨ SYNOPSIS ✨

int arm_mbo_chain (struct most_channel *c , int dir , void
(*compl)(struct mbo *) );

literally just one function call, so simple, so iconic 👑

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🎀 ARGUMENTS 🎀

• c — pointer to interface channel. it's giving "here's the channel, do ur thing"
• dir — direction of the channel. which way are we going bestie, pick a lane
• compl — pointer to completion function. the lil callback that gets to celebrate when things finish 🎉

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🌸 DESCRIPTION 🌸

so this function allocates buffer objects — including the containing DMA coherent buffer — and puts them in the fifo. that's the whole assignment, and it ate, no cap.

now listen: buffers of Rx channels get put in the kthread fifo, which means they're immediately submitted to the HDM. like, no waiting around, straight in. slay ✨

it returns the number of allocated and enqueued MBOs. so the return value is literally the receipts of how much work got done 💖

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👀 SEE ALSO 👀

the kernel file ./drivers/most/core.c, plus the whole friendgroup of related functions — go read them, iykyk:

• list_pop_mbo(9)
• most_free_mbo_coherent(9)
• flush_channel_fifos(9)
• flush_trash_fifo(9)
• get_channel(9)
• arm_mbo(9)
• most_submit_mbo(9)
• most_write_completion(9)
• most_get_mbo(9)
• most_put_mbo(9)
• most_read_completion(9)
• most_start_channel(9)
• most_stop_channel(9)
• most_register_component(9)
• most_deregister_component(9)
• most_register_interface(9)
• most_deregister_interface(9)
• most_stop_enqueue(9)
• most_resume_enqueue(9)

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and that's the page, bestie 🦋 it lives in ./drivers/most and the version date is October 2026 — go forth and arm those chains, you're gonna do amazing, mwah 💜