Re: [PATCH resend 5/5] libata-scsi: fix MODE SELECT translation for Control mode page

From: Tom Yan <tom.ty89@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Hannes Reinecke <hare@suse.de>,
	Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-next@vger.kernel.org
Subject: Re: [PATCH resend 5/5] libata-scsi: fix MODE SELECT translation for Control mode page
Date: Fri, 22 Jul 2016 05:50:18 +0800	[thread overview]
Message-ID: <CAGnHSEnSQcxcaJopGnVusC9Q41qHKkdr4QQDmymFSxVEH6zvPQ@mail.gmail.com> (raw)
In-Reply-To: <20160721212600.GF23759@htj.duckdns.org>

As I've mentioned in the comment/message, there is no ATA command
needed to be sent to the device, since it only toggles a bit in
dev->flags. See that there is no ata_taskfile constructed in
ata_mselect_control().

On 22 July 2016 at 05:26, Tejun Heo <tj@kernel.org> wrote:
> On Fri, Jul 22, 2016 at 02:41:54AM +0800, tom.ty89@gmail.com wrote:
>> @@ -3854,6 +3852,8 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
>>               if (ata_mselect_control(qc, p, pg_len, &fp) < 0) {
>>                       fp += hdr_len + bd_len;
>>                       goto invalid_param;
>> +             } else {
>> +                     goto skip; /* No ATA command to send */
>
> Hmmm... I'm a bit confused.  Why is mselect_control path different
> from mselect_caching in terms of qc handling?
>
> Thanks.
>
> --
> tejun