mas_prev(9)

🌸 mas_prev(9) — the Kernel API Manual glow-up 🌸

okay bestie, so you're diving into the maple tree kernel API and you found mas_prev and you're like "what does this even do" — don't worry, I got you. This is literally from the Kernel API Manual and we're gonna make it make sense 💅

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✨ SYNOPSIS ✨

void * mas_prev (struct ma_state *mas , unsigned long min );

like, it returns a void * and takes a maple state pointer and an unsigned long minimum. iconic signature tbh.

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🎀 ARGUMENTS 🎀

• mas — The maple state. this is your main character struct, the whole vibe check of the operation lives here 🗺️
• min — The minimum value to check. like, don't go below this, fr fr.

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💖 DESCRIPTION 💖

okay so here's the tea:

You must hold rcu_read_lock or the write lock. no cap. if you don't, that's not it.

It will reset mas to ma_start if the status is ma_none. so like, it knows how to start over, very self-aware of it.

Will stop on not searchable nodes. periodt. it's not gonna keep digging where it shouldn't.

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🔥 RETURN 🔥

the previous value, or NULL. that's it. that's the whole return section. simple, clean, slay.

ngl if you get NULL back, maybe check your locks first bestie 😭

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🦋 SEE ALSO 🦋

okay bestie here's the whole friend group, all from the kernel file ./lib/maple_tree.c:

• mas_prealloc_calc(9)
• mas_wr_preallocate(9)
• mas_insert(9)
• mas_alloc_cyclic(9)
• mas_walk(9)
• mte_dead_walk(9)
• mt_free_walk(9)
• mas_store(9)
• mas_store_gfp(9)
• mas_store_prealloc(9)
• mas_preallocate(9)
• mas_next(9)
• mas_next_range(9)
• mt_next(9)
• mas_prev_range(9)
• mt_prev(9)
• mas_pause(9)
• mas_find_setup(9)
• mas_find(9)
• mas_find_range(9)
• mas_find_rev_setup(9)
• mas_find_rev(9)
• mas_find_range_rev(9)
• mas_erase(9)
• mas_nomem(9)
• mas_nomem_nofail(9)
• mtree_load(9)
• mtree_store_range(9)
• mtree_store(9)
• mtree_insert_range(9)
• mtree_insert(9)
• mtree_alloc_cyclic(9)
• mtree_erase(9)
• __mt_dup(9)
• mtree_dup(9)
• __mt_destroy(9)
• mtree_destroy(9)
• mt_find(9)
• mt_find_after(9)

like, that's the whole squad. go read them. iykyk 💜

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and that's the page bestie! this lil guy lives in ./lib and the manual's dated October 2026 — go forth and traverse that maple tree, you absolute icon 👑✨