__cond_acquires_shared(9)

✨ __cond_acquires_shared ✨

ok so bestie, this is a page from the Kernel API Manual and we're talking about __cond_acquires_shared(9) — a function attribute, and honestly it's giving "quietly iconic little annotation that keeps the context analysis from losing its mind" 🫶

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🌸 NAME 🌸

__cond_acquires_shared — a function attribute that says "this function conditionally acquires a context lock, and it takes it in shared mode" ✨ like, not always, but sometimes, and the compiler should know.

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🎀 SYNOPSIS 🎀

__cond_acquires_shared (ret , x );

yes, it's written exactly like that, commas and all, we don't question the formatting, we respect it 💅

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🦋 ARGUMENTS 🦋

• ret — the abstract value the function returns when it did acquire the context lock. basically the "was it a yes?" signal 🫡
• x — pointer to the context lock instance. the actual lock thing we're talking about, no cap.

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🌈 DESCRIPTION 🌈

okay so here's the vibe: this is a function attribute that declares your function conditionally acquires the given context lock instance x, and it takes it with shared access — but it does not release it. nope. not its job. releasing is somebody else's main character arc 😌

and the way it tells you when the lock got acquired? the return value, ret. that's the whole signal. ret is like the little flag that says "yeah bestie, we got it" 🚩

ret can be any one of these, exactly:

true, false, nonzero, 0, nonnull, NULL

that's the whole list, don't improvise 💖

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🧚 SEE ALSO 🧚

okay this is the part where the page just absolutely spills the whole friend group, and honestly? obsessed. the kernel file in question lives at ./include/linux/compiler-context-analysis.h 🔥 and here's everyone:

• __guarded_by(9)
• __pt_guarded_by(9)
• context_lock_struct(9)
• disable_context_analysis(9)
• enable_context_analysis(9)
• __no_context_analysis(9)
• context_unsafe(9)
• __context_unsafe(9)
• context_unsafe_alias(9)
• token_context_lock(9)
• token_context_lock_instance(9)
• __must_hold(9)
• __must_not_hold(9)
• __acquires(9)
• __cond_acquires(9)
• __releases(9)
• __cond_releases(9)
• __acquire(9)
• __release(9)
• __must_hold_shared(9)
• __acquires_shared(9)
• __releases_shared(9)
• __acquire_shared(9)
• __release_shared(9)
• __acquire_ret(9)
• __acquire_shared_ret(9)

like, the entire shared-vs-not-shared cinematic universe is right there, go read them, iykyk 🍓

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fr fr though: this is about declaring behaviour so the context analysis can do its thing. don't just sprinkle it around for the aesthetic — the annotation has to actually match what your function does 💀

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and that's the page!! brought to you from ./include/linux, dated October 2026 — mwah, go annotate something, ily, bye 💜🧚‍♀️