Re: [PATCH] Remove 'unhandled error code' messages

[Rob Evers <revers@redhat.com>]

On 11/10/2011 10:44 AM, James Bottomley wrote:
> On Thu, 2011-11-10 at 16:18 +0100, Hannes Reinecke wrote:
>> On 11/10/2011 03:55 PM, James Bottomley wrote:
>>> On Thu, 2011-11-10 at 15:12 +0100, Hannes Reinecke wrote:
>>>> scsi_io_completion() tries to take some action based on
>>>> the command result and sense code. It also displays
>>>> 'unhandled error code' or 'unhandled sense code' in case
>>>> no special handling was found.
>>>> This serves as an additional source of confusion to
>>>> the unsuspecting user, as the message in fact means
>>>> 'everything okay, no special casing required',
>>>> and not 'oh gosh, something has happened and the system
>>>> couldn't deal with it'.
>>> It means we're just about to fail the command with an error.  That's not
>>> really an everything ok case.
>>>
>>> Sometimes, you're right, this is the correct thing to do silently, but
>>> often it's not.  So, same question to you as to Rob: What are the
>>> circumstances you want silent failure for and can you special case them?
>>>

This is what I have seen (recent rhel6):

Nov 10 03:42:06 <host-name> kernel: sd 2:0:0:1: [sdb] Unhandled error code
Nov 10 03:42:06 <host-name> kernel: sd 2:0:0:1: [sdb] Result: 
hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
Nov 10 03:42:06 <host-name> kernel: sd 2:0:0:1: [sdb] CDB: Read(10): 28 
00 00 4e 91 e0 00 00 20 00
Nov 10 03:42:06 <host-name> kernel: end_request: I/O error, dev sdb, 
sector 5149152

Would the correct solution for this case to be to make description:

     ""

or a special case, something like:

     "Couldn't connect before timeout period"

as I posted here:
http://marc.info/?l=linux-scsi&m=131854148309464&w=2

In the post I made above, I also liked

+			description = "Default sense code handling";

for the sense case.

and potentially something like

+	description = "Default host byte handling";

for the host_byte case when a host_byte isn't handled as
an alternative catch-all.