STRUCT INTERVAL_TREE_SPAN_ITER(9)

🦋 NAME 🦋

ok so this is a page from the Kernel API Manual (the <kbd>9</kbd> section, iykyk) and it's all about struct interval_tree_span_iter — literally its whole job is Find used and unused spans. bestie that's it, that's the vibe 💅

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✨ SYNOPSIS ✨

here's the struct, character for character, no cap:

struct interval_tree_span_iter {
    union {
      unsigned long start_hole;
      unsigned long start_used;
    };
    union {
      unsigned long last_hole;
      unsigned long last_used;
    };
    int is_hole;
 };

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🎀 Members 🎀

okay let's meet the cast 👑

• {unnamed_union} — anonymous. yes bestie, it has no name, it's mysterious like that 🙈
• start_hole — Start of an interval for a hole when is_hole == 1
• start_used — Start of a used interval when is_hole == 0
• {unnamed_union} — anonymous again. two anonymous unions, they're twins 🫶
• last_hole — Inclusive end of an interval for a hole when is_hole == 1
• last_used — Inclusive end of a used interval when is_hole == 0
• is_hole — 0 == used, 1 == is_hole, -1 == done iteration ⭐

tiny note bestie: those last_* fields are inclusive ends, not exclusive. don't come for me, that's just what the page says 💖

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🌸 Description 🌸

okay so picture this: this iterator travels over spans in an interval tree 🔥 and here's the plot twist — it does not return nodes. instead it classifies each span as either a hole, where no nodes intersect, or a used, which is fully covered by nodes. it's giving main character energy with a whole identity of its own 💀

each iteration step toggles between hole and used until the entire range is covered. and the returned spans? they always fully cover the requested range. always. periodt ✨

also the iterator is greedy 🍓 — it always returns the largest hole or used possible, consolidating all consecutive nodes. it's not here to be subtle, it wants the biggest span and it gets it 👑

Use interval_tree_span_iter_done to detect end of iteration. that's your "are we there yet" check, don't skip it 🧚

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💜 SEE ALSO 💜

• Kernel file ./include/linux/interval_tree.h

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and that's the whole page bestie 🌈 — brought to you by ./include/linux, dated October 2026, from the struct inter...ee_span_iter(9) corner of the Kernel API Manual. go forth and iterate, ily 💖🦋✨