Re: [EXTERNAL] Re: [PATCH] padata: Fix possible divide-by-0 panic in padata_mt_helper()

[Kamlesh Gurudasani]

Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> writes:

> On Tue, Aug 20, 2024 at 12:06:47PM GMT, Herbert Xu wrote:
>> On Mon, Aug 19, 2024 at 06:29:52PM -0400, Daniel Jordan wrote:
>> >
>> > The DIV_ROUND_UP approach reads a bit nicer to me, but I can imagine
>> > oddball cases where rounding up is undesirable (say, near-zero values
>> > for size, min_chunk, and align; padata_work_alloc_mt returns many fewer
>> > works than requested; and a single unit of work is very expensive) so
>> > that rounding up makes a bigger difference.  So, the way it now is seems
>> > ok.
>> 
>> In that case let's do the max ahead of the align check:
>> 
>> 	ps.chunk_size = max(ps.chunk_size, 1ul);
>> 	ps.chunk_size = roundup(ps.chunk_size, job->align);
>> 
>> If we do it after then it may come out unaligned (e.g., job->align = 8
>> and ps.chunk_size = 1).
>
> Sure, I think Kamlesh was the first to suggest max, so maybe Kamlesh
> would like to make the change.  I'll send a patch otherwise.
Thanks for consideration, Daniel. I'll send a patch.

cheers,
Kamlesh