hsi_alloc_msg(9)

🎀 NAME 🎀

okay bestie, welcome to the hsi_alloc_msg(9) page from the Kernel API Manual — this one is literally all about allocating an HSI message 💖

✨ SYNOPSIS ✨

struct hsi_msg * hsi_alloc_msg (unsigned int nents , gfp_t flags );

🦋 ARGUMENTS 🦋

• nents — the number of memory entries, periodt.
• flags — the kernel allocation flags, no cap.

🌸 DESCRIPTION 🌸

so here's the tea: nents can be 0. This mainly makes sense for read transfer. In that case, HSI drivers will call the complete callback when there is data to be read without consuming it 👑

Return NULL on failure, or a pointer to an hsi_msg on success. That's the whole vibe check 💅

🌈 SEE ALSO 🌈

Kernel file ./drivers/hsi/hsi_core.c — and yes, the whole friend group is here:

• hsi_port_unregister_clients(9)
• hsi_unregister_controller(9)
• hsi_register_controller(9)
• hsi_register_client_driver(9)
• hsi_put_controller(9)
• hsi_alloc_controller(9)
• hsi_free_msg(9)
• hsi_async(9)
• hsi_claim_port(9)
• hsi_release_port(9)
• hsi_register_port_event(9)
• hsi_unregister_port_event(9)
• hsi_event(9)
• hsi_get_channel_id_by_name(9)

signing off from ./drivers/hsi, October 2026 — hsi_alloc_msg(9) out, slay 💅💖