Messages in this thread | | | Subject | Re: [PATCH v2] staging: erofs: keep corrupted fs from crashing kernel in erofs_namei() | From | Gao Xiang <> | Date | Fri, 15 Feb 2019 18:33:30 +0800 |
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Hi Dan,
On 2019/2/15 17:35, Dan Carpenter wrote: > On Fri, Feb 15, 2019 at 05:32:33PM +0800, Chao Yu wrote: >> On 2019/2/15 15:57, Dan Carpenter wrote: >>> On Fri, Feb 15, 2019 at 03:02:25PM +0800, Chao Yu wrote: >>>> On 2019/2/1 20:16, Gao Xiang wrote: >>>>> + /* >>>>> + * on-disk error, let's only BUG_ON in the debugging mode. >>>>> + * otherwise, it will return 1 to just skip the invalid name >>>>> + * and go on (in consideration of the lookup performance). >>>>> + */ >>>>> + DBG_BUGON(qd->name > qd->end); >>>> >>>> qd->name == qd->end is not allowed as well? >>>> >>>> So will it be better to return directly here? >>>> >>>> if (unlikely(qd->name >= qd->end)) { >>>> DBG_BUGON(1); >>>> return 1; >>>> } >>> >>> Please don't add likely/unlikely() annotations unless you have >>> benchmarked it and it makes a difference. >> >> Well, it only occur for corrupted image, since the image is readonly, so it >> is really rare. > > The likely/unlikely() annotations make the code harder to read. It's > only worth it if it's is a speedup on a fast path.
Yes, I think abuse of using likely/unlikely() should be avoided (I agree that some odd likely/unlikely() exists in the current code, that should be cleaned up).
However, likely/unlikely()s are also clearly highlight critical/corner paths). I personally think it should be used in case-by-case basis rather than a unified conclusion ("that makes the code harder to read").
Thanks, Gao Xiang
> > regards, > dan carpenter > > _______________________________________________ > devel mailing list > devel@linuxdriverproject.org > http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel >
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