Re: [Bug 115351] New: redundant pointless messages

Douglas Gilbert
2016-03-28T00:49:57Z

On 16-03-27 03:48 PM, bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=115351
>
> Bug ID: 115351
> Summary: redundant pointless messages
> Product: IO/Storage
> Version: 2.5
> Kernel Version: All
> Hardware: All
> OS: Linux
> Tree: Mainline
> Status: NEW
> Severity: low
> Priority: P1
> Component: SCSI
> Assignee: linux-scsi@vger.kernel.org
> Reporter: spamme@ecybernard.com
> Regression: No
>
> First, why does it have to log "Very big device" 44 times on startup.
> Second, Given the size of ALL modern hard drives an array of almost any size
> probably triggers this warning.

That will only occur if this function:

static int sd_try_rc16_first(struct scsi_device *sdp)
{
if (sdp->host->max_cmd_len < 16)
return 0;
if (sdp->try_rc_10_first)
return 0;
if (sdp->scsi_level > SCSI_SPC_2)
return 1;
if (scsi_device_protection(sdp))
return 1;
return 0;
}

returns zero and the disks in question have more than 2**32 - 1
logical blocks. [For 512 byte blocks that is 2 TiB, for 4096 byte
blocks that is 16 TiB.] Modern SCSI (SAS) disks should be reporting
SPC-3 or higher compliance as should virtual disks in any properly
configured array.

> Suggestion: just get rid of this pointless message. Maybe you should just
> always use 16, or maybe for future proofing go to 24 or 32.

The 2**64 logical block maximum in the READ CAPACITY(16) response
should be sufficient, for the time being.

Request: find out why sd_try_rc16_first() returns zero.

Doug Gilbert