On Sun, 19 Nov 2006 17:32:11 -0500 Jeff Mahoney wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Al Viro wrote: > > On Sun, Nov 19, 2006 at 11:04:33AM -0800, Randy Dunlap wrote: > >> Andi Kleen wrote: > >>>>> I would copy a relatively simple C implementation, like > >>>>> arch/h8300/lib/checksum.c > >>>> As long as the h8300 version has the same output as the x86 version. > >>> The trouble is that the different architecture have different output > >>> for csum_partial. So you already got a bug when someone wants to move > >>> file systems. > >>> > >>> -Andi > >> That argues for having only one version of it (in a lib.; my preference) > >> -or- Every module having its own local copy/version of it. :( > > > > Wrong. csum_partial() result is defined modulo 0xffff and it's basically > > "whatever's convenient as intermediate for this architecture". > > > > reiserfs use of it is just plain broken. net/* is fine, since all > > final uses are via csum_fold() or equivalents. > > > > Note that reiserfs use is broken in another way: it takes fixed-endian value > > and feeds it to cpu_to_le32(). IOW, even if everything had literally the > > same csum_partial(), the value it shits on disk would be endian-dependent. > > Oh great. Even better. :(
Even more: MD/raid (=m) is broken in this way also. It uses csum_partial(), which isn't present (CONFIG_NET=n). Kernel: arch/x86_64/boot/bzImage is ready (#9) Building modules, stage 2. MODPOST 101 modules WARNING: "csum_partial" [drivers/md/md-mod.ko] undefined! make[1]: *** [__modpost] Error 1 make: *** [modules] Error 2 CONFIG_MD=y CONFIG_BLK_DEV_MD=m CONFIG_MD_LINEAR=m # CONFIG_MD_RAID0 is not set CONFIG_MD_RAID1=m # CONFIG_MD_RAID10 is not set # CONFIG_MD_RAID456 is not set CONFIG_MD_MULTIPATH=m # CONFIG_MD_FAULTY is not set CONFIG_BLK_DEV_DM=y CONFIG_DM_DEBUG=y CONFIG_DM_CRYPT=m CONFIG_DM_SNAPSHOT=y CONFIG_DM_MIRROR=y CONFIG_DM_ZERO=m CONFIG_DM_MULTIPATH=y CONFIG_DM_MULTIPATH_EMC=m --- ~Randy full broken config for MD: http://oss.oracle.com/~rdunlap/configs/config-md-csum - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
