read_seqcount_latch_retry(9)

💅 read_seqcount_latch_retry — a Kernel API Manual moment

okay so bestie, welcome to the Kernel API Manual, and today's main character is read_seqcount_latch_retry(9) — the little function that tells you whether your read section needs a do-over. yes, THE vibe check of the latch world. 🎀

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✨ NAME ✨

read_seqcount_latch_retry — end a seqcount_latch_t read section 🫶

like, you opened a read section, you did your lil reading, and now you're closing it out and asking the kernel "was that valid tho?" and it answers you. iconic behaviour honestly.

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🌸 SYNOPSIS 🌸

int read_seqcount_latch_retry (const seqcount_latch_t *s , unsigned start );

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🦋 ARGUMENTS 🦋

• s — Pointer to seqcount_latch_t. yes it's a pointer, yes it's const, no you do not get to mess with it 💅
• start — count, from read_seqcount_latch. this is the lil souvenir you grabbed on the way in so you can compare it on the way out. iykyk.

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⭐ RETURN ⭐

true if a read section retry is required, else false.

that's it, that's the whole verdict. true = bestie the data moved, run it back 😭. false = you're good, ship it 🔥.

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🌈 SEE ALSO 🌈

so many siblings, it's giving big family energy. the whole squad lives in the Kernel file ./include/linux/seqlock.h, and here's literally every single one of them 👑

• the seqcount core girlies — seqcount_init(9), SEQCNT_ZERO(9), __read_seqcount_begin(9), raw_read_seqcount_begin(9), read_seqcount_begin(9), raw_read_seqcount(9), raw_seqcount_try_begin(9), raw_seqcount_begin(9), __read_seqcount_retry(9), read_seqcount_retry(9)
• write-side behaviour — raw_write_seqcount_begin(9), raw_write_seqcount_end(9), write_seqcount_begin_nested(9), write_seqcount_begin(9), write_seqcount_end(9), raw_write_seqcount_barrier(9), write_seqcount_invalidate(9)
• the latch squad (our people 🫶) — SEQCNT_LATCH_ZERO(9), seqcount_latch_init(9), raw_read_seqcount_latch(9), read_seqcount_latch(9), raw_read_seqcount_latch_retry(9), raw_write_seqcount_latch(9), write_seqcount_latch_begin(9), write_seqcount_latch(9), write_seqcount_latch_end(9)
• seqlock basics — seqlock_init(9), DEFINE_SEQLOCK(9), read_seqbegin(9), read_seqretry(9), write_seqlock(9), write_sequnlock(9), write_seqlock_bh(9), write_sequnlock_bh(9), write_seqlock_irq(9), write_sequnlock_irq(9), write_seqlock_irqsave(9), write_sequnlock_irqrestore(9)
• excl reader crew — read_seqlock_excl(9), read_sequnlock_excl(9), read_seqlock_excl_bh(9), read_sequnlock_excl_bh(9), read_seqlock_excl_irq(9), read_sequnlock_excl_irq(9), read_seqlock_excl_irqsave(9), read_sequnlock_excl_irqrestore(9)
• begin-or-lock besties — read_seqbegin_or_lock(9), need_seqretry(9), done_seqretry(9), read_seqbegin_or_lock_irqsave(9), done_seqretry_irqrestore(9), scoped_seqlock_read(9)

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ngl bestie, this page is tiny but it's doing so much. always check your retry, always respect the sequence count, and never ever pretend a retry wasn't needed. the kernel will notice 🙈

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💜 that's the whole page! brought to you straight from ./include/linux, dated October 2026 — no cap, that's the source and version, so you know it's legit. mwah, go read your latches responsibly 🧚✨🍓