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Date:   Tue, 14 Jun 2022 11:20:32 -0700
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Subject: Re: [PATCH RFC v2 03/18] scsi: core: Implement reserved command
 handling
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To:     Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        John Garry <john.garry@huawei.com>, axboe@kernel.dk,
        jejb@linux.ibm.com, martin.petersen@oracle.com, brking@us.ibm.com,
        hare@suse.de, hch@lst.de
Cc:     linux-block@vger.kernel.org, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
        chenxiang66@hisilicon.com
References: <1654770559-101375-1-git-send-email-john.garry@huawei.com>
 <1654770559-101375-4-git-send-email-john.garry@huawei.com>
 <b4a0ede5-95a3-4388-e808-7627b5484d01@opensource.wdc.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <b4a0ede5-95a3-4388-e808-7627b5484d01@opensource.wdc.com>
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On 6/13/22 00:01, Damien Le Moal wrote:
> On 6/9/22 19:29, John Garry wrote:
>> +	/*
>> +	 * This determines how many commands the HBA will set aside
>> +	 * for internal commands. This number will be added to
>> +	 * @can_queue to calcumate the maximum number of simultaneous
> 
> s/calcumate/calculate
> 
> But this is weird. For SATA, can_queue is 32. Having reserved commands,
> that number needs to stay the same. We cannot have more than 32 tags.
> I think keeping can_queue as the max queue depth with at most
> nr_reserved_cmds tags reserved is better.
> 
>> +	 * commands sent to the host.
>> +	 */
>> +	int nr_reserved_cmds;

+1 for Damien's request. I also prefer to keep can_queue as the maximum
queue depth, whether or not nr_reserved_cmds has been set.

Thanks,

Bart.