On Thu, Apr 23, 2009 at 02:25:54PM -0400, Martin K. Petersen wrote:
> >>>>> "Konrad" == Konrad Rzeszutek <konrad@xxxxxxxxxxxxxxx> writes:
>
> [Printing physical block size]
>
> Konrad> With the changes in the read_capacity_16 (where you set the
> Konrad> hw_sector_size) this won't be printed (at least on first probe).
>
> Why not?
The read_capacity_16 sets the sdkp->hw_sector_size to sector_size:
@@ -1402,6 +1413,7 @@ static int read_capacity_10(struct scsi_
sector_size = (buffer[4] << 24) | (buffer[5] << 16) |
(buffer[6] << 8) | buffer[7];
+ sdkp->hw_sector_size = sector_size;
lba = (buffer[0] << 24) | (buffer[1] << 16) |
(buffer[2] << 8) | buffer[3];
That function also returns that value, which sd_read_capacity assigns to the
sector_size variable. So when the check for sdkp->hw_sector_size
inequality is reached, it is skiped as sdkp->hw_sector_size ==
sector_size. No?
>
> [root@10 ~]# modprobe scsi_debug dev_size_mb=1024 num_parts=4 physblk_exp=3
> scsi 6:0:0:0: Direct-Access Linux scsi_debug 0004 PQ: 0 ANSI: 5
> sd 6:0:0:0: Attached scsi generic sg3 type 0
> sd 6:0:0:0: [sdc] 2097152 512-byte logical blocks: (1.07 GB/1.00 GiB)
> sd 6:0:0:0: [sdc] 4096-byte physical blocks
Is that doing a read_capacity_16 or _10?
>
>
> Konrad> Another question - should the Documentation/*.txt have an entry
> Konrad> about what a 'logical block', and 'physical block' is
> Konrad> vs. 'hardware sector' ?
>
> Well, another item on my todo list is to kill the notion of hardware
> sector completely. The protocols have been referring to logical blocks
> for ages.
Do they refer to physical blocks as well?
>
> It hasn't been a big problem until now because logical block size has
> been equal to the hardware sector size. That's no longer a valid
> assumption.
Right.
>
> --
> Martin K. Petersen Oracle Linux Engineering
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