Messages in this thread | | | Subject | Re: [PATCH -next v2 2/9] blk-iocost: improve hanlder of match_u64() | From | Yu Kuai <> | Date | Thu, 1 Dec 2022 21:47:35 +0800 |
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Hi,
在 2022/12/01 18:08, Tejun Heo 写道: > On Thu, Dec 01, 2022 at 10:15:53AM +0800, Yu Kuai wrote: >> Hi, >> >> 在 2022/12/01 4:32, Tejun Heo 写道: >>> On Wed, Nov 30, 2022 at 09:21:49PM +0800, Li Nan wrote: >>>> From: Yu Kuai <yukuai3@huawei.com> >>>> >>>> 1) There are one place that return value of match_u64() is not checked. >>>> 2) If match_u64() failed, return value is set to -EINVAL despite that >>>> there are other possible errnos. >>> >>> Ditto. Does this matter? >>> >> >> It's not a big deal, but I think at least return value of match_u64() >> should be checked, we don't want to continue with invalid input, right? > > Yeah, sure. > >> By the way, match_u64() can return -ERANGE, which can provide more >> specific error messge to user. > > I'm really not convinced going over 64bit range would be all that difficult > to spot whether the error code is -EINVAL or -ERANGE. There isn't anything > wrong with returning -ERANGE but the fact that that particular function > returns an error code doesn't necessarily mean that it *must* be forwarded. > > Imagine that we used sscanf(buf, "%llu", &value) to parse the number > instead. We'd only know whether the parsing would have succeeded or not and > would probably return -EINVAL on failure and the behavior would be just > fine. This does not matter *at all*. > > So, idk, I'm not necessarily against it but changing -EINVAL to -ERANGE is > pure churn. Nothing material is being improved by that change.
Thanks for the review and explanation, I'll just keep the addition of return value checking of the former 2 patches.
Thanks, Kuai
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