nd_region_acquire_lane(9)

✨ nd_region_acquire_lane — the kernel API manual, bestie edition ✨

okay so we're in the Kernel API Manual today and the star of the show is nd_region_acquire_lane(9) — literally the function that hands you a lane and locks it down. let's get into it 🎀

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🌸 NAME 🌸

nd_region_acquire_lane — allocate and lock a lane, that's it, that's the whole vibe 💅

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🦋 SYNOPSIS 🦋

unsigned int nd_region_acquire_lane (struct nd_region *nd_region );

copy it exactly like that, no cap, the spacing is part of the aesthetic (jk but also don't touch it) 🙈

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🍓 ARGUMENTS 🍓

• nd_region — the region id and the number of lanes possible. like it's doing two jobs at once and honestly? main character energy 👑

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💜 DESCRIPTION 💜

so a lane correlates to a log slot in the BTT. that's the whole concept, bestie. 🫶

lanes are shared across CPUs using a static lane = cpu % num_lanes mapping, with a per-lane mutex to serialize access. so the CPUs are all up in the same lane rotation and the mutex keeps them from stepping on each other's toes — it's giving polite chaos 🌈

⚠️ real talk: callers must be in sleepable context. not optional, not negotiable. do not come in here with your atomic nonsense, the mutex will simply not have it 😭

the only in-tree caller is BTT's ->submit_bio handler (btt_read_pg / btt_write_pg). just those two. iconic of them to be the only ones invited to the party fr fr ✨

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/nvdimm/region_devs.c
• nd_region_to_nstype(9)
• generic_nvdimm_flush(9)
• nvdimm_has_flush(9)

go read those too, iykyk 💖

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and that's the page!! 🌟 this lil beauty comes to you from ./drivers/nvdimm, dated October 2026, living in the Kernel API Manual — mwah, stan the nvdimm region code for clear skin 🧚💜