Re: [PATCH] ibmvscsis: Do not send aborted task response

From: "Bryant G. Ly" <bryantly@linux.vnet.ibm.com>
To: Bart Van Assche <Bart.VanAssche@sandisk.com>,
	"nab@linux-iscsi.org" <nab@linux-iscsi.org>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"target-devel@vger.kernel.org" <target-devel@vger.kernel.org>,
	"seroyer@linux.vnet.ibm.com" <seroyer@linux.vnet.ibm.com>
Subject: Re: [PATCH] ibmvscsis: Do not send aborted task response
Date: Fri, 7 Apr 2017 12:01:25 -0500	[thread overview]
Message-ID: <63af0be8-f36f-a42d-9898-a7ef642a8c17@linux.vnet.ibm.com> (raw)
In-Reply-To: <1491583008.2559.12.camel@sandisk.com>


On 4/7/17 11:36 AM, Bart Van Assche wrote:
> On Fri, 2017-04-07 at 11:12 -0500, Bryant G. Ly wrote:
>> So from this stack trace it looks like the ibmvscsis driver is sending an
>> extra response through send_messages even though an abort was issued.
>> IBMi, reported this issue internally when they were testing the driver,
>> because their client didn't like getting a response back for the aborted op.
>> They are only expecting a TMR from the abort request, NOT the aborted op.
> Hello Bryant,
>
> What is the root cause of this behavior? Why is it that the behavior of
> the ibmvscsi_tgt contradicts what has been implemented in the LIO core?
> Sorry but the patch at the start of this thread looks to me like an
> attempt to paper over the problem instead of addressing the root cause.
>
> Thanks,
>
IBMi clients received a response for an aborted operation, so they sent an abort tm request.
Afterwards they get a CRQ response to the op that they aborted. That should not happen, because they are only supposed to get a response for the tm request NOT the aborted operation.
Looking at the code it looks like it is due to send messages, processing a response without checking to see if it was an aborted op.
This patch addresses a bug within the ibmvscsis driver and the fact that it SENT a response to the aborted operation(which is wrong since) without looking at what LIO core had done.
The driver isn't supposed to send any response to the aborted operation, BUT only a response to the abort tm request, which LIO core currently does.

-Bryant