Re: [PATCH] Make efi-pstore return a unique id

[Tony Luck]

On Fri, Nov 1, 2013 at 1:57 PM, Seiji Aguchi <seiji.aguchi@xxxxxxx> wrote:
>> What about feeding the bytes of all three integers into a non-cryptographic hash function?
>> Using this way you get a cheap unique id.
>
> It is reasonable to me.

How does efivars backend handle "unlink(2)" in the pstore file system.
pstore will call the backend->erase function passing the "id".  The
backend should then erase the right record from persistent storage.

With the  ((timestamp * 100 + part) * 100 + count function - you can
easily reverse it to find timestamp, part and count - would that make life
easier for the backend to find the record to be erased?  If you use a
hash function you will need to check each record and compute the
hash to see if it matches (probably not a big deal because the backend
will generally only hold a handful of records).

-Tony
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/