Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <44d3878a-363e-632c-8e7d-d8bb016ac8df@interlog.com>
Date:   Tue, 28 Mar 2023 19:35:30 -0400
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.9.0
Reply-To: dgilbert@interlog.com
Subject: Re: [PATCH v3 01/11] scsi: scsi_debug: Fix check for sdev queue full
Content-Language: en-CA
To:     John Garry <john.g.garry@oracle.com>, jejb@linux.ibm.com,
        martin.petersen@oracle.com
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        bvanassche@acm.org, kernel test robot <oliver.sang@intel.com>
References: <20230327074310.1862889-1-john.g.garry@oracle.com>
 <20230327074310.1862889-2-john.g.garry@oracle.com>
From:   Douglas Gilbert <dgilbert@interlog.com>
In-Reply-To: <20230327074310.1862889-2-john.g.garry@oracle.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 2023-03-27 03:43, John Garry wrote:
> There is a report that the blktests scsi/004 test for "TASK SET FULL" (TSF)
> now fails.
> 
> The condition upon we should issue this TSF is when the sdev queue is
> full. The check for a full queue has an off-by-1 error. Previously we
> would increment the number of requests in the queue after testing if the
> queue would be full, i.e. test if one less than full. Since we now use
> scsi_device_busy() to count the number of requests in the queue, this
> would already account for the current request, so fix the test for queue
> full accordingly.
> 
> Fixes: 151f0ec9ddb5 ("scsi: scsi_debug: Drop sdebug_dev_info.num_in_q")
> Reported-by: kernel test robot <oliver.sang@intel.com>
> Link: https://lore.kernel.org/oe-lkp/202303201334.18b30edc-oliver.sang@intel.com
> Signed-off-by: John Garry <john.g.garry@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com

Thanks.

> ---
>   drivers/scsi/scsi_debug.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
> index 7ed117e78bd4..782515abca2c 100644
> --- a/drivers/scsi/scsi_debug.c
> +++ b/drivers/scsi/scsi_debug.c
> @@ -5580,7 +5580,7 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
>   		int num_in_q = scsi_device_busy(sdp);
>   		int qdepth = cmnd->device->queue_depth;
>   
> -		if ((num_in_q == (qdepth - 1)) &&
> +		if ((num_in_q == qdepth) &&
>   		    (atomic_inc_return(&sdebug_a_tsf) >=
>   		     abs(sdebug_every_nth))) {
>   			atomic_set(&sdebug_a_tsf, 0);