| Message ID | 20231203193307.542794-34-yury.norov@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | bitops: add atomic find_bit() operations | expand |
On Sun, Dec 3, 2023 at 8:34 PM Yury Norov <yury.norov@gmail.com> wrote: > Fix opencoded find_and_set_bit(), which also suppresses potential > KCSAN warning. > > CC: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> > Signed-off-by: Yury Norov <yury.norov@gmail.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- a/arch/sh/boards/mach-x3proto/ilsel.c > +++ b/arch/sh/boards/mach-x3proto/ilsel.c > @@ -99,8 +99,8 @@ int ilsel_enable(ilsel_source_t set) > } > > do { > - bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS); > - } while (test_and_set_bit(bit, &ilsel_level_map)); > + bit = find_and_set_bit(&ilsel_level_map, ILSEL_LEVELS); > + } while (bit >= ILSEL_LEVELS); > > __ilsel_enable(set, bit); BTW, I don't think the old code worked as intended: the first time no free bit is found, bit would have been ILSEL_LEVELS, and test_and_set_bit() would have returned false, thus terminating the loop, and continuing with an out-of-range bit value? Hence to work correctly, bit ILSEL_LEVELS of ilsel_level_map should have been initialized to one? Or am I missing something? The new code does not have that issue. Anyway, this should probably never happen in real life. Gr{oetje,eeting}s, Geert
diff --git a/arch/sh/boards/mach-x3proto/ilsel.c b/arch/sh/boards/mach-x3proto/ilsel.c index f0d5eb41521a..7fadc479a80b 100644 --- a/arch/sh/boards/mach-x3proto/ilsel.c +++ b/arch/sh/boards/mach-x3proto/ilsel.c @@ -99,8 +99,8 @@ int ilsel_enable(ilsel_source_t set) } do { - bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS); - } while (test_and_set_bit(bit, &ilsel_level_map)); + bit = find_and_set_bit(&ilsel_level_map, ILSEL_LEVELS); + } while (bit >= ILSEL_LEVELS); __ilsel_enable(set, bit);
Fix opencoded find_and_set_bit(), which also suppresses potential KCSAN warning. CC: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Signed-off-by: Yury Norov <yury.norov@gmail.com> --- arch/sh/boards/mach-x3proto/ilsel.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)