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Date: Mon, 14 Nov 2022 15:23:54 -0800
From: Isaac Manjarres <isaacmanjarres@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Ard Biesheuvel <ardb@kernel.org>,
	Saravana Kannan <saravanak@google.com>,
	Alasdair Kergon <agk@redhat.com>, Daniel Vetter <daniel@ffwll.ch>,
	Joerg Roedel <joro@8bytes.org>, Mark Brown <broonie@kernel.org>,
	Mike Snitzer <snitzer@kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>, linux-mm@kvack.org,
	iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 03/13] iommu/dma: Force bouncing of the size is not
 cacheline-aligned
Message-ID: <Y3LOCg9FEuFxny0B@google.com>
References: <20221106220143.2129263-1-catalin.marinas@arm.com>
 <20221106220143.2129263-4-catalin.marinas@arm.com>
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In-Reply-To: <20221106220143.2129263-4-catalin.marinas@arm.com>

On Sun, Nov 06, 2022 at 10:01:33PM +0000, Catalin Marinas wrote:
> @@ -1202,7 +1203,10 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
>  			goto out;
>  	}
>  
> -	if (dev_use_swiotlb(dev))
> +	if (dma_sg_kmalloc_needs_bounce(dev, sg, nents, dir))
> +		sg_dma_mark_bounced(sg);
> +
> +	if (dev_use_swiotlb(dev) || sg_is_dma_bounced(sg))
>  		return iommu_dma_map_sg_swiotlb(dev, sg, nents, dir, attrs);

Shouldn't you add a similar check in the iommu_dma_unmap_sg() path to
free any SWIOTLB memory that may have been allocated to bounce a scatter gather
list?