On 02/26/14 07:32, David Dillow wrote:

On Tue, 2014-02-25 at 11:33 +0100, Bart Van Assche wrote:

quoted

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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