29 lines
957 B
ReStructuredText
29 lines
957 B
ReStructuredText
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.. title:: clang-tidy - linuxkernel-must-use-errs
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linuxkernel-must-use-errs
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=========================
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Checks Linux kernel code to see if it uses the results from the functions in
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``linux/err.h``. Also checks to see if code uses the results from functions that
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directly return a value from one of these error functions.
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This is important in the Linux kernel because ``ERR_PTR``, ``PTR_ERR``,
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``IS_ERR``, ``IS_ERR_OR_NULL``, ``ERR_CAST``, and ``PTR_ERR_OR_ZERO`` return
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values must be checked, since positive pointers and negative error codes are
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being used in the same context. These functions are marked with
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``__attribute__((warn_unused_result))``, but some kernel versions do not have
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this warning enabled for clang.
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Examples:
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.. code-block:: c
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/* Trivial unused call to an ERR function */
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PTR_ERR_OR_ZERO(some_function_call());
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/* A function that returns ERR_PTR. */
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void *fn() { ERR_PTR(-EINVAL); }
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/* An invalid use of fn. */
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fn();
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