Re: [PATCH v2 4/5] blk-iocost: fix sleeping in atomic context warnning

Tejun Heo
2022-12-08T15:59:44Z

On Mon, Dec 05, 2022 at 05:39:33PM +0800, Yu Kuai wrote:
> Hi, Tejun
>
> 在 2022/11/23 18:22, Yu Kuai 写道:
> > Hi, Tejun
> >
> > 在 2022/11/23 8:42, Tejun Heo 写道:
> > > On Tue, Nov 22, 2022 at 05:14:29PM -0700, Jens Axboe wrote:
> > > > > > Then match_strdup() and kfree() in match_NUMBER() can be replaced with
> > > > > > get_buffer() and put_buffer().
> > > > >
> > > > > Sorry about the late reply. Yeah, something like this.
> >
>
> I wonder can we just use arary directly in stack? The max size is just
> 24 bytes, which should be fine:
>
> HEX: "0xFFFFFFFFFFFFFFFF" --> 18
> DEC: "18446744073709551615" --> 20
> OCT: "01777777777777777777777" --> 23
>
> Something like:
> #define U64_MAX_SIZE 23
> static int match_strdup_local(const substring_t *s, char *buf)
> {
> size_t len = s->to - s->from;
>
> if (len > U64_MAX_SIZE)
> return -ERANGE;
>
> if (!s->from)
> return -EINVAL;
>
> memcpy(buf, s->from, len);
> buf[len] = '\0';
> return 0;
> }
>
> static int match_u64int(substring_t *s, u64 *result, int base)
> {
> char buf[U64_MAX_SIZE + 1];
> int ret;
> u64 val;
>
> ret = match_strdup_local(s, buf);
> if (ret)
> return ret;
> ret = kstrtoull(buf, base, &val);
> if (!ret)
> *result = val;;
> return ret;
> }

Oh yeah, absolutely. That's much better.

Thanks.

--
tejun