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From: Joerg Roedel <joro@8bytes.org>
To: Tomasz Figa <tfiga@chromium.org>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v2 1/2] iommu/dma: Respect __GFP_DMA and __GFP_DMA32 in incoming GFP flags
Date: Wed, 26 Jul 2017 11:15:46 +0200	[thread overview]
Message-ID: <20170726091545.GC15833@8bytes.org> (raw)
In-Reply-To: <20170704135556.21704-1-tfiga@chromium.org>

On Tue, Jul 04, 2017 at 10:55:55PM +0900, Tomasz Figa wrote:
> Current implementation of __iommu_dma_alloc_pages() keeps adding
> __GFP_HIGHMEM to GFP flags regardless of whether other zone flags are
> already included in the incoming flags. If __GFP_DMA or __GFP_DMA32 is
> set at the same time as __GFP_HIGHMEM, the allocation fails due to
> invalid zone flag combination.
> 
> Fix this by checking for __GFP_DMA and __GFP_DMA32 in incoming GFP flags
> and adding __GFP_HIGHMEM only if they are not present.
> 
> Signed-off-by: Tomasz Figa <tfiga@chromium.org>

Isn't it better to mask out __GFP_DMA and __GFP_DMA32 in the allocation
flags and only take them into account for iova allocation?

When the IOMMU re-maps the DMA to this memory it doesn't matter where it
is in system memory.



	Joerg

  parent reply	other threads:[~2017-07-26  9:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-04 13:55 Tomasz Figa
2017-07-04 13:55 ` [PATCH v2 2/2] iommu/dma: Use __GFP_NOWARN only for high-order allocations Tomasz Figa
2017-07-26  9:24   ` Joerg Roedel
2017-07-26  9:29     ` Tomasz Figa
2017-07-26  9:15 ` Joerg Roedel [this message]
2017-07-26  9:26   ` [PATCH v2 1/2] iommu/dma: Respect __GFP_DMA and __GFP_DMA32 in incoming GFP flags Tomasz Figa

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