Messages in this thread | | | Date | Mon, 1 Mar 2021 16:31:09 -0600 | From | Segher Boessenkool <> | Subject | Re: [PATCH v1 01/15] powerpc/uaccess: Remove __get_user_allowed() and unsafe_op_wrap() |
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On Tue, Mar 02, 2021 at 09:02:54AM +1100, Daniel Axtens wrote: > Checkpatch does have one check that is relevant: > > CHECK: Macro argument reuse 'p' - possible side-effects? > #36: FILE: arch/powerpc/include/asm/uaccess.h:482: > +#define unsafe_get_user(x, p, e) do { \ > + if (unlikely(__get_user_nocheck((x), (p), sizeof(*(p)), false)))\ > + goto e; \ > +} while (0)
sizeof (of something other than a VLA) does not evaluate its operand. The checkpatch warning is incorrect (well, it does say "possible" -- it just didn't find a possible problem here).
You can write bla = sizeof *p++; and p is *not* incremented.
Segher
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