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From: Christoph Hellwig <hch@infradead.org>
To: Pankaj Suryawanshi <pankajssuryawanshi@gmail.com>
Cc: linux-mm@kvack.org, Michal Hocko <mhocko@kernel.org>,
	linux-kernel@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
	iommu@lists.linux-foundation.org
Subject: Re: DMA-API attr - DMA_ATTR_NO_KERNEL_MAPPING
Date: Wed, 26 Jun 2019 10:51:31 -0700	[thread overview]
Message-ID: <20190626175131.GA17250@infradead.org> (raw)
In-Reply-To: <CACDBo55GfomD4yAJ1qaOvdm8EQaD-28=etsRHb39goh+5VAeqw@mail.gmail.com>

On Wed, Jun 26, 2019 at 10:12:45PM +0530, Pankaj Suryawanshi wrote:
> [CC: linux kernel and Vlastimil Babka]

The right list is the list for the DMA mapping subsystem, which is
iommu@lists.linux-foundation.org.  I've also added that.

> > I am writing driver in which I used DMA_ATTR_NO_KERNEL_MAPPING attribute
> > for cma allocation using dma_alloc_attr(), as per kernel docs
> > https://www.kernel.org/doc/Documentation/DMA-attributes.txt  buffers
> > allocated with this attribute can be only passed to user space by calling
> > dma_mmap_attrs().
> >
> > how can I mapped in kernel space (after dma_alloc_attr with
> > DMA_ATTR_NO_KERNEL_MAPPING ) ?

You can't.  And that is the whole point of that API.


  reply	other threads:[~2019-06-26 17:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-26 16:41 Pankaj Suryawanshi
2019-06-26 16:42 ` Pankaj Suryawanshi
2019-06-26 17:51   ` Christoph Hellwig [this message]
2019-06-28 16:29     ` Pankaj Suryawanshi
2019-07-01 14:09       ` Robin Murphy
2019-07-01 17:47         ` Pankaj Suryawanshi
2019-07-01 17:52           ` Pankaj Suryawanshi
2019-07-01 17:54           ` Robin Murphy
2019-07-01 18:07             ` Pankaj Suryawanshi
2019-07-01 18:36           ` Pankaj Suryawanshi

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