Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
compiler-context-analysys: Add __cond_releases()
Useful for things like unlock fastpaths, which on success release the
lock.
Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Marco Elver <elver@google.com>
Link: https://patch.msgid.link/20260121111213.634625032@infradead.org
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include/linux/compiler-context-analysis.h
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include/linux/compiler-context-analysis.h
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*/
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#define __releases(...) __releases_ctx_lock(__VA_ARGS__)
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/*
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* Clang's analysis does not care precisely about the value, only that it is
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* either zero or non-zero. So the __cond_acquires() interface might be
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* misleading if we say that @ret is the value returned if acquired. Instead,
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* provide symbolic variants which we translate.
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*/
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#define __cond_acquires_impl_not_true(x, ...) __try_acquires##__VA_ARGS__##_ctx_lock(0, x)
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#define __cond_acquires_impl_not_false(x, ...) __try_acquires##__VA_ARGS__##_ctx_lock(1, x)
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#define __cond_acquires_impl_not_nonzero(x, ...) __try_acquires##__VA_ARGS__##_ctx_lock(0, x)
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#define __cond_acquires_impl_not_0(x, ...) __try_acquires##__VA_ARGS__##_ctx_lock(1, x)
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#define __cond_acquires_impl_not_nonnull(x, ...) __try_acquires##__VA_ARGS__##_ctx_lock(0, x)
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#define __cond_acquires_impl_not_NULL(x, ...) __try_acquires##__VA_ARGS__##_ctx_lock(1, x)
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/**
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* __cond_releases() - function attribute, function conditionally
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* releases a context lock exclusively
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* @ret: abstract value returned by function if context lock releases
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* @x: context lock instance pointer
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*
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* Function attribute declaring that the function conditionally releases the
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* given context lock instance @x exclusively. The associated context(s) must
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* be active on entry. The function return value @ret denotes when the context
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* lock is released.
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*
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* @ret may be one of: true, false, nonzero, 0, nonnull, NULL.
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*
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* NOTE: clang does not have a native attribute for this; instead implement
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* it as an unconditional release and a conditional acquire for the
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* inverted condition -- which is semantically equivalent.
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*/
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#define __cond_releases(ret, x) __releases(x) __cond_acquires_impl_not_##ret(x)
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/**
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* __acquire() - function to acquire context lock exclusively
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* @x: context lock instance pointer