linux-kernel - Re: [PATCH 2/2] iommu/vt-d: Remove dead code in device

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Date:	Wed, 17 Dec 2014 14:41:44 -0700
From:	Jerry Hoemann <jerry.hoemann@...com>
To:	Joerg Roedel <joro@...tes.org>
Cc:	iommu@...ts.linux-foundation.org,
	Alex Williamson <alex.williamson@...hat.com>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>,
	Myron Stowe <mstowe@...hat.com>
Subject: Re: [PATCH 2/2] iommu/vt-d: Remove dead code in device_notifier

On Wed, Dec 17, 2014 at 11:43:37AM +0100, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@...e.de>
> 
> This code only runs when action == BUS_NOTIFY_REMOVED_DEVICE,
> so it can't be BUS_NOTIFY_DEL_DEVICE.
> 
> Signed-off-by: Joerg Roedel <jroedel@...e.de>
> ---
>  drivers/iommu/intel-iommu.c | 8 --------
>  1 file changed, 8 deletions(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 7610121..40dfbc0 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -4029,14 +4029,6 @@ static int device_notifier(struct notifier_block *nb,
>  	if (action != BUS_NOTIFY_REMOVED_DEVICE)
>  		return 0;
>  
> -	/*
> -	 * If the device is still attached to a device driver we can't
> -	 * tear down the domain yet as DMA mappings may still be in use.
> -	 * Wait for the BUS_NOTIFY_UNBOUND_DRIVER event to do that.
> -	 */
> -	if (action == BUS_NOTIFY_DEL_DEVICE && dev->driver != NULL)
> -		return 0;
> -
>  	domain = find_domain(dev);
>  	if (!domain)
>  		return 0;
> -- 
> 1.9.1

Joerg,

Tested this along w/ other patch of the set.

Instrumentation showed that the removed code wouldn't have been executed
during VM power on/power off.

Thanks!

Tested-by: Jerry Hoemann <jerry.hoemann@...com>


-- 

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Jerry Hoemann            Software Engineer              Hewlett-Packard

3404 E Harmony Rd. MS 36                        phone:  (970) 898-1022
Ft. Collins, CO 80528                           FAX:    (970) 898-0707
                                                email:  jerry.hoemann@...com
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