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Subject: Re: [PATCH 2/3] scsi: fnic: Stop setting scsi_cmnd.tag
To:     John Garry <john.garry@huawei.com>, Christoph Hellwig <hch@lst.de>,
        Bart Van Assche <bvanassche@acm.org>
Cc:     satishkh@cisco.com, sebaddel@cisco.com, kartilak@cisco.com,
        jejb@linux.ibm.com, martin.petersen@oracle.com,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
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From:   Hannes Reinecke <hare@suse.de>
Message-ID: <9ec48220-68aa-e2d1-5555-d7307e29260d@suse.de>
Date:   Mon, 16 Aug 2021 13:11:08 +0200
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On 8/16/21 12:00 PM, John Garry wrote:
> On 14/08/2021 13:35, Hannes Reinecke wrote:
>> On 8/14/21 9:39 AM, Christoph Hellwig wrote:
>>> On Fri, Aug 13, 2021 at 08:17:45PM -0700, Bart Van Assche wrote:
>>>> On 8/13/21 6:49 AM, John Garry wrote:
>>>>> It is never read. Setting it and the request tag seems dodgy
>>>>> anyway.
>>>>
>>>> This is done because there is code in the SCSI error handler that may
>>>> allocate a SCSI command without allocating a tag. See also
>>>> scsi_ioctl_reset().
> 
> Right, so we just get a loan of the tag of a real request. fnic driver
> comment:
> 
> "Really should fix the midlayer to pass in a proper request for ioctls..."
> 
>>>
>>> Yes.  Hannes had a great series to stop passing the pointless scsi_cmnd
>>> to the reset methods.  Hannes, any chance you coul look into
>>> resurrecting that?
>>>
>> Sure.
> 
> The latest iteration of that series - at v7 - still passed that fake
> SCSI command to the reset method, and the reset method allocated the
> internal command.
> 
> So will we change change scsi_ioctl_reset() to allocate an internal
> command, rather than the LLDD?
> 
Nah, Christoph was talking about my patch series to revamp the SCSI
error handler.
With that one we'll be passing the respective objects to the SCSI EH
functions (ie struct scsi_device for eh_device_reset()), doing away with
the need to allocate an internal command for ioctl reset.
Currently revamping the patchset, should be ready later this week.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
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