On 27/07/16 19:08, Andrew Cooper wrote: > Introduce and use the nonnull attribute to help the compiler catch NULL > parameters being passed to function which require their parameters not to be > NULL. Experimentally, GCC 4.9 on Debian Jessie only warns of non-NULL-ness > from immediate callers, so propagate the attributes out to all helpers. > > A sample error looks like: > > mem_sharing.c: In function ‘mem_sharing_nominate_page’: > mem_sharing.c:884:13: error: null argument where non-null required (argument > 3) [-Werror=nonnull] > amfn = get_gfn_type_access(ap2m, gfn, NULL, &ap2ma, 0, NULL); > ^ > > As part of this, replace the get_gfn_type_access() macro with an equivalent > static inline function for extra type safety, and the ability to be annotated. > > Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
At a high level this looks like it's probably an improvement; I'd like to hear opinions of people who tend to have stronger opinions here first. One technical comment... > --- > CC: Jan Beulich <jbeul...@suse.com> > CC: Tim Deegan <t...@xen.org> > CC: George Dunlap <george.dun...@eu.citrix.com> > CC: Tamas K Lengyel <tamas.leng...@zentific.com> > --- > xen/include/asm-x86/p2m.h | 19 +++++++++++-------- > xen/include/xen/compiler.h | 2 ++ > 2 files changed, 13 insertions(+), 8 deletions(-) > > diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h > index 194020e..e35d59c 100644 > --- a/xen/include/asm-x86/p2m.h > +++ b/xen/include/asm-x86/p2m.h > @@ -380,9 +380,9 @@ void p2m_unlock_and_tlb_flush(struct p2m_domain *p2m); > * After calling any of the variants below, caller needs to use > * put_gfn. ****/ > > -mfn_t __get_gfn_type_access(struct p2m_domain *p2m, unsigned long gfn, > - p2m_type_t *t, p2m_access_t *a, p2m_query_t q, > - unsigned int *page_order, bool_t locked); > +mfn_t __nonnull(1, 3, 4) __get_gfn_type_access( __get_gfn_type_access() explicitly tolerates p2m being NULL, so '1' should be removed from the list (both here and below). -George _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
