On Sat, Dec 06, 2014 at 06:32:00PM -0500, George Spelvin wrote: > Well, *that* was a rabbit hole. It seems like an obviously good idea, > but let's just say that crypto/ is non-obvious. (No, it didn't take me 2 > months of work; I just got sidetracked a lot because it was discouraging.) > But now that my cleanup patches there are getting reviewed, I can answer. Yeah, at this point I think we're better off having our own open-coded version of siphash. We have in the past exported the core of a crypto hash which could be used by both /dev/random and the version in crypto/ with all of the crypto packaging and overhead, but it's probably not worth it here --- siphash is much smaller than say, any of the SHA algorithms. (The same is true for our use of crc32c, BTW --- if you can demonstrate on a ramdisk --- or a super fast PCIe attached flash, but randisks are cheaper --- that there are workloads were we are paying for overheads caused by the crypto layer, it might make sense to export the crc32c tables, and have an ext4-specific crc32c function. OTOH, the main resaon why we probably want to keep on using the crypto/ is that we can more easily take advantage of hardware acceleration on some platforms, which wouldn't be the case with siphash.) Cheers, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
