On Mon, 2010-09-13 at 13:40 -0700, Nicholas A. Bellinger wrote: > 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..? > Hi Mike and Hannes, So after a quick test using Open-iSCSI 32-bit x86 VM w/ v2.6.27 and LIO-Target 64-bit powerpc w/v2.6.36-rc3 with this libcrypto patch I do not see any HeaderDigest or DataDigest failures using the exiting slicing by 1x crypto/crc32c.c code on 64-bit BIG_ENDIAN. While I am at it I will also try OpenSuse 11.2 and RHEL6 B2 x86_64 VMs for good measure. So the appropiate endian conversion does occur in chksum_final() and __chksum_finup() code. My apologies for the earier confusion. Thanks again, --nab -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
