Documentation/sparse.txt: document context annotations for lock checking (6e976631) · Commits · 戴 / test

The context feature of sparse is used with the Linux kernel sources to check for imbalanced uses of locks. Document the annotations defined in include/linux/compiler.h that tell sparse what to expect when a lock is held on function entry, exit, or both. Signed-off-by:

Ed Cashin <ecashin@coraid.com> Reviewed-by:

Josh Triplett <josh@joshtriplett.org> Acked-by:

Christopher Li <sparse@chrisli.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

Documentation/sparse.txt

+18 −0

Original line number	Diff line number	Diff line
		@@ -49,6 +49,24 @@ be generated without __CHECK_ENDIAN__.
		__bitwise - noisy stuff; in particular, __le/__be are that. We really
		don't want to drown in noise unless we'd explicitly asked for it.

		Using sparse for lock checking
		~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

		The following macros are undefined for gcc and defined during a sparse
		run to use the "context" tracking feature of sparse, applied to
		locking. These annotations tell sparse when a lock is held, with
		regard to the annotated function's entry and exit.

		__must_hold - The specified lock is held on function entry and exit.

		__acquires - The specified lock is held on function exit, but not entry.

		__releases - The specified lock is held on function entry, but not exit.

		If the function enters and exits without the lock held, acquiring and
		releasing the lock inside the function in a balanced way, no
		annotation is needed. The tree annotations above are for cases where
		sparse would otherwise report a context imbalance.

		Getting sparse
		~~~~~~~~~~~~~~

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