Re: [PATCH v2] scsi: introduce short_inquiry flag for broken host adapters

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Tue, 2015-09-15 at 16:27 +0200, Vitaly Kuznetsov wrote:
> Vitaly Kuznetsov <vkuznets@redhat.com> writes:
> 
> > Some host adapters (e.g. Hyper-V storvsc) are known for not respecting the
> > SPC-2/3/4 requirement for 'INQUIRY data (see table ...) shall contain at
> > least 36 bytes'. As a result we get tons on 'scsi 0:7:1:1: scsi scan:
> > INQUIRY result too short (5), using 36' messages on console. This can be
> > problematic for slow consoles. Introduce short_inquiry host template flag
> > to avoid printing error messages for such adapters.
> >
> > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> > ---
> > Changes since v1:
> > - This is a successor of previously sent "scsi_scan: move 'INQUIRY result
> >   too short' message to debug level" patch. Instead of moving the message
> >   to debug level for all adapters introduce a special 'short_inquiry' flag
> >   for host template [inspired by James Bottomley].
> 
> James,
> 
> sorry for the ping but can you please let me know your opinion? This is
> not a 'cosmetic fix', serial port on Hyper-V is extremely slow and users
> get softlockups just because we output too much. Here is a freshly
> booted guest with SCSI and FC adapters connected:
> 
> # dmesg | grep -c INQUIRY
> 2076

It needs a review ... preferably from someone who validates that we
don't get any adverse impact from the missing inquiry data

> (my other pernding '[PATCH] scsi_scan: don't dump trace when
> scsi_prep_async_scan() is called twice' is related to the same issue).

So does this.

James


> See also: https://lkml.org/lkml/2015/9/6/119
> 
> Thanks,
> 
> [...]
>