Messages in this thread | | | Subject | Re: [PATCH 0/2] lio-target: Add support for libcrypto crc32c and crc32-intel offload | From | "Nicholas A. Bellinger" <> | Date | Mon, 13 Sep 2010 13:40:06 -0700 |
| |
On Mon, 2010-09-13 at 15:35 -0500, Mike Christie wrote: > On 09/13/2010 02:50 PM, Nicholas A. Bellinger wrote: > >> IE the in-kernel crc32c routines apparently weren't able to > >> calculate the checksum in an endianness-independent manner. > >> So a CRC calculated on a BE machine would fail to be validated by a > >> LE machine and vice versa. > >> > >> Has this been fixed / verified? > >> > > > >> From taking a look at crypto/crc32c.c it still appears AFAICT to not be > > big endian safe. I was planning to test this patch on some powerpc/ppc > > hardware with v2.6.36-rc4 in the next days, but it looks like > > lio-core-2.6.git will need a seperate crypto/crc32c.c patch to function > > properly on big endian arches. > > > > There was this bug that was fixed a couple years ago: > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=ef19454bd437b2ba14c9cda1de85debd9f383484 > since then I think we have not had problems.
Hi Mike,
Thanks for the pointer on this, I will give it a shot on powerpc and see what happens.
FYI, I was under the assumption that for BIG_ENDIAN that crc32c() still needed an bitshift for the returned value. This is what we had been doing with our old internal do_crc() code here:
http://git.kernel.org/?p=linux/kernel/git/nab/lio-core-2.6.git;a=blob;f=drivers/target/lio-target/iscsi_crc.c;hb=83559072b27eb8cd92abb9a3fc9be85018c5db06#l138
AFAICT there is still nothing that makes crypto/crc32c.c big endian safe, unless I am overlooking something obvious..?
Best,
--nab
| |