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

[KY Srinivasan]

> -----Original Message-----
> From: James Bottomley [mailto:James.Bottomley@xxxxxxxxxxxxxxxxxxxxx]
> Sent: Tuesday, September 15, 2015 11:24 AM
> To: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Cc: linux-scsi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; KY Srinivasan
> <kys@xxxxxxxxxxxxx>; Long Li <longli@xxxxxxxxxxxxx>; Dexuan Cui
> <decui@xxxxxxxxxxxxx>
> Subject: Re: [PATCH v2] scsi: introduce short_inquiry flag for broken host
> adapters
> 
> On Tue, 2015-09-15 at 16:27 +0200, Vitaly Kuznetsov wrote:
> > Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> 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@xxxxxxxxxx>
> > > ---
> > > 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,

I will review the code and test this as well.

Regards,

K. Y
> 
> James
> 
> 
> > See also:
> https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2flkml.or
> g%2flkml%2f2015%2f9%2f6%2f119&data=01%7c01%7ckys%40microsoft.com
> %7c7a6e9ccabb2f43c0a01108d2bdfad826%7c72f988bf86f141af91ab2d7cd011
> db47%7c1&sdata=t3IGLMiG2sU4VJfmGiYKGMy22d3IxHbGQZop63nrV7Y%3d
> >
> > Thanks,
> >
> > [...]
> >
> 
> 

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