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Subject: Re: [PATCH 2/7] iommu/dma-iommu: Split iommu_dma_map_msi_msg in two
 parts
To:     Christoph Hellwig <hch@infradead.org>
Cc:     linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
        logang@deltatee.com, douliyangs@gmail.com,
        miquel.raynal@bootlin.com, marc.zyngier@arm.com,
        jason@lakedaemon.net, tglx@linutronix.de, joro@8bytes.org,
        robin.murphy@arm.com, bigeasy@linutronix.de,
        linux-rt-users@vger.kernel.org
References: <20190418172611.21561-1-julien.grall@arm.com>
 <20190418172611.21561-3-julien.grall@arm.com>
 <20190423070823.GA12114@infradead.org>
From:   Julien Grall <julien.grall@arm.com>
Message-ID: <7af177e1-dfd9-2a91-3fd9-dfe53a6a9014@arm.com>
Date:   Tue, 23 Apr 2019 11:55:34 +0100
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Hi,

On 4/23/19 8:08 AM, Christoph Hellwig wrote:
> On Thu, Apr 18, 2019 at 06:26:06PM +0100, Julien Grall wrote:
>> +int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
>>   {
>> +	struct device *dev = msi_desc_to_dev(desc);
>>   	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>>   	struct iommu_dma_cookie *cookie;
>>   	unsigned long flags;
>>   
>> +	if (!domain || !domain->iova_cookie) {
>> +		desc->iommu_cookie = NULL;
>> +		return 0;
>> +	}
>>   
>>   	cookie = domain->iova_cookie;
>>   
>> @@ -908,10 +908,33 @@ void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
>>   	 * of an MSI from within an IPI handler.
>>   	 */
>>   	spin_lock_irqsave(&cookie->msi_lock, flags);
>> +	desc->iommu_cookie = iommu_dma_get_msi_page(dev, msi_addr, domain);
>>   	spin_unlock_irqrestore(&cookie->msi_lock, flags);
>>   
>> +	return (desc->iommu_cookie) ? 0 : -ENOMEM;
> 
> No need for the braces.  Also I personally find a:
> 
> 	if (!desc->iommu_cookie)
> 		return -ENOMEM;
> 	return 0;
> 
> much more readable, but that might just be personal preference.

I am happy either way. I will use your suggestion in the next version.

Cheers,

-- 
Julien Grall