On Tue, Apr 21, 2009 at 02:29:54PM -0700, Randy Dunlap wrote: > > Fix READ CAPACITY 10 with drives over 1TB > > > > Shifting an unsigned char implicitly casts it to a signed int. This > > caused 'lba' to sign-extend and Linux would then try READ CAPACITY 16 > > which was not supported by at least one drive. Making 'lba' an unsigned > > int ensures that sign extension will not occur. > > > > Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx> > > > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > > index 3fcb64b..c856b1b 100644 > > --- a/drivers/scsi/sd.c > > +++ b/drivers/scsi/sd.c > > @@ -1373,7 +1373,7 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp, > > int sense_valid = 0; > > int the_result; > > int retries = 3; > > - sector_t lba; > > + unsigned lba; > > sector_t is either unsigned long or u64, depending on CONFIG_LBD. > Are you saying (implying) that the higher-order bits of it don't matter here? > If so, I'd just like for that to be clear(er). We're reading 32 bits of information from the drive response. The top 32 bits are implicitly zero. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- 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
