Messages in this thread | | | Date | Fri, 11 Aug 2023 15:31:01 +0200 | Subject | Re: [PATCH v2 2/6] bitmap: replace _reg_op(REG_OP_ALLOC) with bitmap_set() | From | Rasmus Villemoes <> |
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On 11/08/2023 14.56, Yury Norov wrote: > On Fri, Aug 11, 2023 at 08:21:33AM +0200, Rasmus Villemoes wrote: >> On 11/08/2023 02.57, Yury Norov wrote: >>> _reg_op(REG_OP_ALLOC) duplicates bitmap_set(). Fix it. >>> >>> Signed-off-by: Yury Norov <yury.norov@gmail.com> >>> --- >>> lib/bitmap.c | 5 ++++- >>> 1 file changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/lib/bitmap.c b/lib/bitmap.c >>> index 3a589016f5e0..c9afe704fe4b 100644 >>> --- a/lib/bitmap.c >>> +++ b/lib/bitmap.c >>> @@ -1352,9 +1352,12 @@ EXPORT_SYMBOL(bitmap_release_region); >>> */ >>> int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) >>> { >>> + unsigned int nbits = pos + BIT(order); >>> + >> >> That really doesn't sound right. Have you added self-tests for these >> functions first and then used those to catch regressions? > > When bitmap_allocate_region() is broken, almost every arch build fails > to boot. Can you explain what exactly looks wrong to you?
The number of bits we are about to set should not be [position in bitmap to start from] + [2^order]. The second half of that patch was
- return __reg_op(bitmap, pos, order, REG_OP_ALLOC); + bitmap_set(bitmap, pos, nbits); + return 0;
so instead of setting 1<<nbits starting at pos, you're now setting pos+(1<<nbits) starting at pos. How is that correct?
Rasmus
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