read_seqlock_excl(9)

✨ read_seqlock_excl ✨

okay so bestie, welcome to the Kernel API Manual entry for read_seqlock_excl(9) — yes that's the manual name, yes I'm folding it in here, we move 💅

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🌸 NAME 🌸

read_seqlock_excl — like, it begins a seqlock_t locking reader section. that's the whole vibe 🎀

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🦋 SYNOPSIS 🦋

void read_seqlock_excl (seqlock_t *sl );

literally copy that exactly, no cap ✨

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💖 ARGUMENTS 💖

• sl — pointer to seqlock_t. that's it. that's the argument. iconic minimalism 🫶

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👑 DESCRIPTION 👑

okay so read_seqlock_excl opens a seqlock_t locking reader critical section. a locking reader exclusively locks out both other writers and other locking readers — yes both, the way it's framed with asterisks and italics, take it seriously 😭 — but here's the thing, it does not update the embedded sequence number.

locking readers act like a normal spin_lock/spin_unlock. simple as that, fr fr.

the opened read section must be closed with read_sequnlock_excl — do not leave it hanging, bestie, that's not the move 💀

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🔥 CONTEXT 🔥

if the seqlock_t write section, or other read sections, can be invoked from hardirq or softirq contexts, use the _irqsave or _bh variant of this function instead. like, genuinely, that's a real caveat, not a drill 🙈

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🌈 SEE ALSO 🌈

bestie, buckle up, this list is a whole main character moment 👑

kernel file ./include/linux/seqlock.h plus all of these:

• 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)
• 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)
• SEQCNT_LATCH_ZERO(9)
• seqcount_latch_init(9)
• raw_read_seqcount_latch(9)
• read_seqcount_latch(9)
• raw_read_seqcount_latch_retry(9)
• 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_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)
• 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)
• 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)

like, obsessed with the sheer length of this list ngl 🧚

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cute little sign-off: this page lives in ./include/linux, dated October 2026, and it's the read_seqlock_excl(9) entry of the Kernel API Manual. slay, go lock something responsibly 💜