Ming Zhang wrote: > On Tue, 2006-12-19 at 12:56 +0200, Momchil Velikov wrote: >> Arjan van de Ven wrote: >>> On Mon, 2006-12-18 at 17:12 -0500, Ming Zhang wrote: >>>> See this code piece >>>> >>>> http://lxr.linux.no/source/drivers/scsi/libata-scsi.c?v=2.6.18#L1049 >>>> >>>> 1056 lba |= ((u64)scsicmd[2]) << 24; >>>> 1057 lba |= ((u64)scsicmd[3]) << 16; >>>> 1058 lba |= ((u64)scsicmd[4]) << 8; >>>> 1059 lba |= ((u64)scsicmd[5]); >>>> >>>> it can also be written as >>>> >>>> lba = be32_to_cpu(*(u32 *)(&scsicmd[2]) >> ISO/IEC 9899:1999(E) "6.5 Expressions" [#7] > > read but still can not understand why u list this here. Because this code ba = be32_to_cpu(*(u32 *)(&scsicmd[2]) violates this requirement ISO/IEC 9899:1999(E) "6.5 Expressions" [#7] unless you have checked in all callers of ``scsi_10_lba_len'' (and transitively in their callers, if necessary) that the first parameter in fact does refer to an object of type ``u32'', in which case the above code becomes simply non-robust instead of outright non-conforming. ~velco -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
