Messages in this thread | | | From | Ard Biesheuvel <> | Date | Mon, 18 Jun 2018 17:56:48 +0200 | Subject | Re: [PATCH] efi: cper: avoid using get_seconds() |
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On 18 June 2018 at 17:54, Arnd Bergmann <arnd@arndb.de> wrote: > On Mon, Jun 18, 2018 at 5:50 PM, Ard Biesheuvel > <ard.biesheuvel@linaro.org> wrote: >> On 18 June 2018 at 17:49, Arnd Bergmann <arnd@arndb.de> wrote: >>> On Mon, Jun 18, 2018 at 5:47 PM, Ard Biesheuvel >>> <ard.biesheuvel@linaro.org> wrote: >>>> On 18 June 2018 at 16:17, Arnd Bergmann <arnd@arndb.de> wrote: >>> >>>>> - atomic64_set(&seq, ((u64)get_seconds()) << 32); >>>>> + if (!atomic64_read(&seq)) { >>>>> + time64_t time = ktime_get_real_seconds(); >>>>> + >>>>> + /* >>>>> + * This code is unlikely to still be needed in year 2106, >>>>> + * but just in case, let's use a few more bits for timestamps >>>>> + * after y2038 to be sure they keep increasing monotonically >>>>> + * for the next few hundred years... >>>>> + */ >>>>> + if (time < 0x80000000) >>>>> + atomic64_set(&seq, (ktime_get_real_seconds()) << 32); >>>>> + else >>>>> + atomic64_set(&seq, 0x8000000000000000ull | >>>>> + ktime_get_real_seconds() << 24); >>>>> + } >>>> >>>> Given that these values are never decoded and interpreted as >>>> timestamps, can't we simply switch to the second flavour immediately? >>> >>> I considered that, but the downside would be that all future filenames would >>> come before all past file names. >> >> Won't we have that same problem in 2038? > > No, it goes from 0x7fffffff00000000 to 0x8000000000000000, followed > by 0x8000000001000000. >
Ah, right. I'm with you now :-)
I'll queue this in the efi tree.
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