| Message ID | 20190924105839.110713-2-pankaj.laxminarayan.bharadiya@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add and use sizeof_member macro to bring uniformity | expand |
On Tue, Sep 24, 2019 at 04:28:35PM +0530, Pankaj Bharadiya wrote: > At present we have 3 different macros to calculate the size of a > member of a struct: > - SIZEOF_FIELD > - FIELD_SIZEOF > - sizeof_field > > To bring uniformity in entire kernel source tree let's add > sizeof_member macro. > > Replace all occurrences of above 3 macro's with sizeof_member in > future patches. > > Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> > --- > include/linux/kernel.h | 9 +++++++++ > 1 file changed, 9 insertions(+) Since stddef.h ends up needing this macro, and kernel.h includes stddef.h, why not put this macro in stddef.h instead? Then the open-coded version of it in stddef (your last patch) can use sizeof_member()? Otherwise, yes, looks good. (Though I might re-order the patches so the last patch is the tree-wide swap -- then you don't need the exclusions, I think?) -Kees > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > index 4fa360a13c1e..0b80d8bb3978 100644 > --- a/include/linux/kernel.h > +++ b/include/linux/kernel.h > @@ -79,6 +79,15 @@ > */ > #define round_down(x, y) ((x) & ~__round_mask(x, y)) > > +/** > + * sizeof_member - get the size of a struct's member > + * @T: the target struct > + * @m: the target struct's member > + * Return: the size of @m in the struct definition without having a > + * declared instance of @T. > + */ > +#define sizeof_member(T, m) (sizeof(((T *)0)->m)) > + > /** > * FIELD_SIZEOF - get the size of a struct's field > * @t: the target struct > -- > 2.17.1 >
On Tue, Sep 24, 2019 at 09:22:10AM -0700, Kees Cook wrote: > On Tue, Sep 24, 2019 at 04:28:35PM +0530, Pankaj Bharadiya wrote: > > At present we have 3 different macros to calculate the size of a > > member of a struct: > > - SIZEOF_FIELD > > - FIELD_SIZEOF > > - sizeof_field > > > > To bring uniformity in entire kernel source tree let's add > > sizeof_member macro. > > > > Replace all occurrences of above 3 macro's with sizeof_member in > > future patches. > > > > Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> > > --- > > include/linux/kernel.h | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > Since stddef.h ends up needing this macro, and kernel.h includes > stddef.h, why not put this macro in stddef.h instead? Then the > open-coded version of it in stddef (your last patch) can use > sizeof_member()? > If I understood correctly, Andrew suggested to add such macros in kernel.h https://www.openwall.com/lists/kernel-hardening/2019/06/11/5 Moreover similar type of other macros (like typeof_member & ARRAY_SIZE) are defined in kernel.h But as you pointed out, looks like stddef.h is the right place for this macro. > Otherwise, yes, looks good. (Though I might re-order the patches so the > last patch is the tree-wide swap -- then you don't need the exclusions, > I think?) > I went through your tree. https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=kspp/sizeof_member/full Thank you for reordering the patches. Thanks, Pankaj > -Kees > > > > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > > index 4fa360a13c1e..0b80d8bb3978 100644 > > --- a/include/linux/kernel.h > > +++ b/include/linux/kernel.h > > @@ -79,6 +79,15 @@ > > */ > > #define round_down(x, y) ((x) & ~__round_mask(x, y)) > > > > +/** > > + * sizeof_member - get the size of a struct's member > > + * @T: the target struct > > + * @m: the target struct's member > > + * Return: the size of @m in the struct definition without having a > > + * declared instance of @T. > > + */ > > +#define sizeof_member(T, m) (sizeof(((T *)0)->m)) > > + > > /** > > * FIELD_SIZEOF - get the size of a struct's field > > * @t: the target struct > > -- > > 2.17.1 > > > > -- > Kees Cook
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 4fa360a13c1e..0b80d8bb3978 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -79,6 +79,15 @@ */ #define round_down(x, y) ((x) & ~__round_mask(x, y)) +/** + * sizeof_member - get the size of a struct's member + * @T: the target struct + * @m: the target struct's member + * Return: the size of @m in the struct definition without having a + * declared instance of @T. + */ +#define sizeof_member(T, m) (sizeof(((T *)0)->m)) + /** * FIELD_SIZEOF - get the size of a struct's field * @t: the target struct
At present we have 3 different macros to calculate the size of a member of a struct: - SIZEOF_FIELD - FIELD_SIZEOF - sizeof_field To bring uniformity in entire kernel source tree let's add sizeof_member macro. Replace all occurrences of above 3 macro's with sizeof_member in future patches. Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> --- include/linux/kernel.h | 9 +++++++++ 1 file changed, 9 insertions(+)