On Wed, Oct 28, 2020 at 12:05 PM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > > > > Using kasan_reset_tag() currently results in a function call. As it's > > called quite often from the allocator code this leads to a noticeable > > slowdown. Move it to include/linux/kasan.h and turn it into a static > > inline function. > > > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > > Link: https://linux-review.googlesource.com/id/I4d2061acfe91d480a75df00b07c22d8494ef14b5 > > --- > > include/linux/kasan.h | 5 ++++- > > mm/kasan/hw_tags.c | 5 ----- > > mm/kasan/kasan.h | 6 ++---- > > mm/kasan/sw_tags.c | 5 ----- > > 4 files changed, 6 insertions(+), 15 deletions(-) > > > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > > index 93d9834b7122..6377d7d3a951 100644 > > --- a/include/linux/kasan.h > > +++ b/include/linux/kasan.h > > @@ -187,7 +187,10 @@ static inline void kasan_record_aux_stack(void *ptr) {} > > > > void __init kasan_init_tags(void); > > > > -void *kasan_reset_tag(const void *addr); > > +static inline void *kasan_reset_tag(const void *addr) > > +{ > > + return (void *)arch_kasan_reset_tag(addr); > > It seems that all implementations already return (void *), so the cast > is not needed. arch_kasan_reset_tag() (->__tag_reset() -> __untagged_addr()) preserves the type of the argument, so the cast is needed. > > > +} > > > > bool kasan_report(unsigned long addr, size_t size, > > bool is_write, unsigned long ip); > > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c > > index b372421258c8..c3a0e83b5e7a 100644 > > --- a/mm/kasan/hw_tags.c > > +++ b/mm/kasan/hw_tags.c > > @@ -24,11 +24,6 @@ void __init kasan_init_tags(void) > > pr_info("KernelAddressSanitizer initialized\n"); > > } > > > > -void *kasan_reset_tag(const void *addr) > > -{ > > - return reset_tag(addr); > > -} > > - > > void kasan_poison_memory(const void *address, size_t size, u8 value) > > { > > set_mem_tag_range(reset_tag(address), > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > > index 456b264e5124..0ccbb3c4c519 100644 > > --- a/mm/kasan/kasan.h > > +++ b/mm/kasan/kasan.h > > @@ -246,15 +246,13 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) > > return addr; > > } > > #endif > > -#ifndef arch_kasan_reset_tag > > -#define arch_kasan_reset_tag(addr) ((void *)(addr)) > > -#endif > > #ifndef arch_kasan_get_tag > > #define arch_kasan_get_tag(addr) 0 > > #endif > > > > +/* kasan_reset_tag() defined in include/linux/kasan.h. */ > > +#define reset_tag(addr) ((void *)kasan_reset_tag(addr)) > > The cast is not needed. > > I would also now remove reset_tag entirely by replacing it with > kasan_reset_tag. Having 2 names for the same thing does not add > clarity. Will remove it.
