On Fri, 4 Aug 2017 11:09:53 +0200 Arnd Bergmann <a...@arndb.de> wrote:
> On Fri, Aug 4, 2017 at 9:42 AM, Boris Brezillon > <boris.brezil...@free-electrons.com> wrote: > > On Wed, 14 Jun 2017 23:15:40 +0200 > > Arnd Bergmann <a...@arndb.de> wrote: > > > >> When CONFIG_KASAN is used, we consume a lot of extra stack space: > >> > >> drivers/mtd/chips/cfi_cmdset_0020.c: In function 'do_write_buffer': > >> drivers/mtd/chips/cfi_cmdset_0020.c:603:1: error: the frame size of 2184 > >> bytes is larger than 1536 bytes [-Werror=frame-larger-than=] > >> drivers/mtd/chips/cfi_cmdset_0020.c: In function 'cfi_staa_erase_varsize': > >> drivers/mtd/chips/cfi_cmdset_0020.c:972:1: error: the frame size of 1936 > >> bytes is larger than 1536 bytes [-Werror=frame-larger-than=] > >> drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer': > >> drivers/mtd/chips/cfi_cmdset_0001.c:1841:1: error: the frame size of 1776 > >> bytes is larger than 1536 bytes [-Werror=frame-larger-than=] > >> > >> This marks some functions as noinline_if_stackbloat to keep reduce the > >> overall stack size. > >> > >> Signed-off-by: Arnd Bergmann <a...@arndb.de> > >> --- > >> drivers/mtd/chips/cfi_cmdset_0020.c | 8 ++++---- > >> include/linux/mtd/map.h | 8 ++++---- > >> 2 files changed, 8 insertions(+), 8 deletions(-) > >> > >> diff --git a/drivers/mtd/chips/cfi_cmdset_0020.c > >> b/drivers/mtd/chips/cfi_cmdset_0020.c > >> index 7d342965f392..5eee5e883f55 100644 > >> --- a/drivers/mtd/chips/cfi_cmdset_0020.c > >> +++ b/drivers/mtd/chips/cfi_cmdset_0020.c > >> @@ -244,7 +244,7 @@ static struct mtd_info *cfi_staa_setup(struct map_info > >> *map) > >> } > >> > >> > >> -static inline int do_read_onechip(struct map_info *map, struct flchip > >> *chip, loff_t adr, size_t len, u_char *buf) > >> +static noinline_if_stackbloat int do_read_onechip(struct map_info *map, > >> struct flchip *chip, loff_t adr, size_t len, u_char *buf) > > > > Why do we even need to mark those functions inline in the first place? > > Isn't the compiler smart enough to decide when it should inline things? > > I'm pretty sure it doesn't need the 'inline' keywork. I see that the code was > addedlike this in linux-2.4.0-test3pre3 along with the rest of the mtd layer, > so it has always been 'inline' and nobody ever bothered to remove that > during later cleanups. > > We could probably just mark this function as 'noinline' here and never > inline it, > but I would rather not add more than one variant of noinline_if_stackbloat: > almost all other users of noinline_if_stackbloat are for functions that have > to be inline in normal builds, so it is defined as being either > 'inline' or 'noinline' > depending on whether KASAN is active. Okay. Let's keep it like that then.
