On Tue, Jan 21, 2014 at 11:07 PM, Douglas Gilbert <dgilbert@xxxxxxxxxxxx> wrote:
> On 14-01-21 04:52 AM, Sha Zhengju wrote:
>>
>> From: Sha Zhengju <handai.szj@xxxxxxxxxx>
>>
>> There're severel interfaces to show scsi_level value of scsi_debug,
>> but they're not in consistent. E.g:
>>
>> 1)
>> #cat /sys/bus/pseudo/drivers/scsi_debug/scsi_level
>> 5
>>
>> 2)
>> #cat /proc/scsi/scsi_debug/7
>> scsi_debug adapter driver, version 1.82 [20100324]
>> num_tgts=1, shared (ram) size=1024 MB, opts=0x0, every_nth=0(curr:0)
>> delay=1, max_luns=1, scsi_level=5
>> sector_size=512 bytes, cylinders=130, heads=255, sectors=63
>> number of aborts=0, device_reset=0, bus_resets=0, host_resets=0
>> dix_reads=0 dix_writes=0 dif_errors=0
>>
>> 3)
>> #cat /sys/bus/scsi/devices/7\:0\:0\:0/scsi_level (or lsscsi -l)
>> 6
>>
>> According to the description in scsi.h, "struct scsi_device::scsi_level
>> values. For SCSI devices other than those prior to SCSI-2 (i.e. over
>> 12 years old) this value is (resp[2] + 1) where 'resp' is a byte array
>> of the response to an INQUIRY". For scsi_debug, the resp[2] of INQUIRY
>> is 5 which indicates using SPC-3, but the sysfs's scsi_level will show 6.
>>
>> The aboving 1) and 2) entry export resp[2] of INQUIRY directly, unify
>> them with 3) which is resp[2] + 1.
>
>
> Hmmm. scsi_level is a Linux hack that should be, but cannot
> easily be, replaced. I agree all scsi_level outputs should
> be consistent (and thus equally confusing). Perhaps scsi_debug
> (and the mid-level) should introduce a new variable, something
> like 't10_inq_version' that is rsp[2] from a standard INQUIRY
> response. Since SPC-2, that byte has had the field name VERSION
> and that name seems unlikely to change.
Reasonable for me. Differentiate the standard INQUIRY VERSION value
from linux scsi_level would make it easier to understand.
Thanks for your review!
Thanks,
Sha
>
> Doug Gilbert
>
>
>> Signed-off-by: Sha Zhengju <handai.szj@xxxxxxxxxx>
>> ---
>> drivers/scsi/scsi_debug.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
>> index 80b8b10..a52d0687 100644
>> --- a/drivers/scsi/scsi_debug.c
>> +++ b/drivers/scsi/scsi_debug.c
>> @@ -2866,7 +2866,7 @@ static int scsi_debug_show_info(struct seq_file *m,
>> struct Scsi_Host *host)
>> SCSI_DEBUG_VERSION, scsi_debug_version_date,
>> scsi_debug_num_tgts,
>> scsi_debug_dev_size_mb, scsi_debug_opts, scsi_debug_every_nth,
>> scsi_debug_cmnd_count, scsi_debug_delay,
>> - scsi_debug_max_luns, scsi_debug_scsi_level,
>> + scsi_debug_max_luns, scsi_debug_scsi_level + 1,
>> scsi_debug_sector_size, sdebug_cylinders_per, sdebug_heads,
>> sdebug_sectors_per, num_aborts, num_dev_resets,
>> num_bus_resets,
>> num_host_resets, dix_reads, dix_writes, dif_errors);
>> @@ -3091,7 +3091,7 @@ DRIVER_ATTR(no_uld, S_IRUGO, sdebug_no_uld_show,
>> NULL);
>>
>> static ssize_t sdebug_scsi_level_show(struct device_driver * ddp, char *
>> buf)
>> {
>> - return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_scsi_level);
>> + return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_scsi_level +
>> 1);
>> }
>> DRIVER_ATTR(scsi_level, S_IRUGO, sdebug_scsi_level_show, NULL);
>>
>>
>
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