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Message-ID: <ac2dcfd820fafd19bab1c910c57044e28951b226.camel@linux.ibm.com>
Subject: Re: [PATCH v2 1/5] iommu/s390: Make attach succeed even if the
 device is in error state
From:   Gerd Bayer <gbayer@linux.ibm.com>
To:     Niklas Schnelle <schnelle@linux.ibm.com>
Cc:     Pierre Morel <pmorel@linux.ibm.com>, linux-s390@vger.kernel.org,
        borntraeger@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com,
        gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com,
        svens@linux.ibm.com, linux-kernel@vger.kernel.org,
        Matthew Rosato <mjrosato@linux.ibm.com>, iommu@lists.linux.dev,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jason Gunthorpe <jgg@nvidia.com>
Date:   Mon, 14 Nov 2022 16:05:16 +0100
In-Reply-To: <20221109142903.4080275-2-schnelle@linux.ibm.com>
References: <20221109142903.4080275-1-schnelle@linux.ibm.com>
         <20221109142903.4080275-2-schnelle@linux.ibm.com>
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Hi Niklas,

really just a nit...

On Wed, 2022-11-09 at 15:28 +0100, Niklas Schnelle wrote:
> diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
> index 7fb512bece9a..e2c886bc4376 100644
> --- a/drivers/iommu/s390-iommu.c
> +++ b/drivers/iommu/s390-iommu.c
> @@ -98,6 +98,7 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
>  	struct s390_domain *s390_domain = to_s390_domain(domain);
>  	struct zpci_dev *zdev = to_zpci_dev(dev);
>  	unsigned long flags;
> +	u8 status;
>  	int cc;
>  
>  	if (!zdev)
> @@ -113,8 +114,12 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
>  		zpci_dma_exit_device(zdev);
>  
>  	cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
> -				virt_to_phys(s390_domain->dma_table));
> -	if (cc)
> +				virt_to_phys(s390_domain->dma_table), &status);
> +	/*
> +	 * If the device is undergoing error recovery the reset code
> +	 * will re-establish the new domain.
> +	 */
> +	if (cc && status != ZPCI_PCI_ST_FUNC_NOT_AVAIL)
Operator precedence does "the right thing", but would a more explicit parenthesis 
around (status != ZPCI_PCI_ST_FUNC_NOT_AVAIL) help or hurt here?

>  		return -EIO;
>  	zdev->dma_table = s390_domain->dma_table;

Thank you,
Gerd