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Subject: Re: [smartpqi updates PATCH 8/9] smartpqi: fix isr accessing null
 structure member
To:     Don Brace <don.brace@microchip.com>,
        Mike McGowen <mike.mcgowen@microchip.com>
Cc:     Kevin.Barnett@microchip.com, scott.teel@microchip.com,
        Justin.Lindley@microchip.com, scott.benesh@microchip.com,
        gerry.morong@microchip.com, mahesh.rajashekhara@microchip.com,
        murthy.bhat@microchip.com, balsundar.p@microchip.com,
        joseph.szczypek@hpe.com, jeff@canonical.com, POSWALD@suse.com,
        john.p.donnelly@oracle.com, mwilck@suse.com,
        linux-kernel@vger.kernel.org, hch@infradead.org,
        martin.peterson@oracle.com, jejb@linux.vnet.ibm.com,
        linux-scsi@vger.kernel.org
References: <20210706181618.27960-1-don.brace@microchip.com>
 <20210706181618.27960-9-don.brace@microchip.com>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
Message-ID: <fa3b5d5a-fdd3-48c7-b8d5-1a732b09bf68@molgen.mpg.de>
Date:   Wed, 7 Jul 2021 09:48:07 +0200
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Dear Don, dear Mike,


Am 06.07.21 um 20:16 schrieb Don Brace:
> From: Mike McGowen <mike.mcgowen@microchip.com>
> 
> Correct driver's ISR accessing a data structure member
> that has not been fully initialized during driver init.

Does that crash the Linux kernel?

>    - The pqi queue groups can be null when an interrupt fires.

If it fixes a crash(?), please add a Fixes: tag so it can be backported 
to the stable series.

> Reviewed-by: Kevin Barnett <kevin.barnett@microchip.com>
> Reviewed-by: Scott Benesh <scott.benesh@microchip.com>
> Reviewed-by: Scott Teel <scott.teel@microchip.com>
> Signed-off-by: Mike McGowen <mike.mcgowen@microchip.com>
> Signed-off-by: Don Brace <don.brace@microchip.com>
> ---
>   drivers/scsi/smartpqi/smartpqi_init.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
> index 6f2263abaa8c..eeaf0568b5e3 100644
> --- a/drivers/scsi/smartpqi/smartpqi_init.c
> +++ b/drivers/scsi/smartpqi/smartpqi_init.c
> @@ -7757,11 +7757,11 @@ static int pqi_ctrl_init(struct pqi_ctrl_info *ctrl_info)
>   
>   	pqi_init_operational_queues(ctrl_info);
>   
> -	rc = pqi_request_irqs(ctrl_info);
> +	rc = pqi_create_queues(ctrl_info);

 From a quick look, these two functions are quite different. It’d be 
great if you elaborated a bit in the commit message, what else the new 
function does.

Also, with this change, `pqi_request_irqs()` does not seem to have any 
users anymore. Without your patch:

     $ git grep pqi_request_irqs
     drivers/scsi/smartpqi/smartpqi_init.c:static int 
pqi_request_irqs(struct pqi_ctrl_info *ctrl_info)
     drivers/scsi/smartpqi/smartpqi_init.c:  rc = 
pqi_request_irqs(ctrl_info);

>   	if (rc)
>   		return rc;
>   
> -	rc = pqi_create_queues(ctrl_info);
> +	rc = pqi_request_irqs(ctrl_info);
>   	if (rc)
>   		return rc;
> 


Kind regards,

Paul