Re: [PATCH 3/6] IB/srp: Fail SCSI commands silently

[Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>]

On 02/26/14 07:32, David Dillow wrote:
> On Tue, 2014-02-25 at 11:33 +0100, Bart Van Assche wrote:
>> Do you really think it is essential to introduce a
>> new flag in the block layer for the purpose of suppressing transport
>> layer error messages and to add support for that flag in the block
>> core and in the SCSI mid-layer ? To me it seems a lot simpler to use
>> the existing REQ_QUIET flag.
> 
> Yes, I think you want different semantics -- one is the requestor saying
> "don't complain about this if it fails", the other is the LLD saying
> "this failed due to transport failure, you may or may not want to report
> it, under user control". But it doesn't necessarily have to be a new
> block flag -- it may be as simple as adding a stanza in
> scsi_io_completion() that looks like
> 
> if (cmd->device->sdev_state != SDEV_TRANSPORT_OFFLINE &&
>     user_want_to_silence_transport_errors)
> 	req->cmd_flags |= REQ_QUIET;
> 
> if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
> 	;
> else if (!(req->cmd_flags & REQ_QUIET))
> 	scsi_print_sense("", cmd);

But this approach doesn't suppress the error messages printed by the
block layer due to a transport layer failure. Additionally, the block
layer is neither aware of the SCSI transport layer state nor of the ASC
and ASCQ codes in the sense data. Hence my preference to keep patch 3/6
as it has been posted at the start of this thread.

Bart.

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