Linux-ARM-MSM Archive on lore.kernel.org
 help / color / Atom feed
From: Tom Murphy <murphyt7@tcd.ie>
To: Hillf Danton <hdanton@sina.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	iommu@lists.linux-foundation.org, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Kukjin Kim <kgene@kernel.org>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Andy Gross <agross@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Rob Clark <robdclark@gmail.com>, Heiko Stuebner <heiko@sntech.de>,
	Gerald Schaefer <gerald.schaefer@de.ibm.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-mediatek@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-s390@vger.kernel.org,
	linux-tegra@vger.kernel.org,
	virtualization@lists.linux-foundation.org
Subject: Re: [PATCH V5 3/5] iommu/dma-iommu: Handle deferred devices
Date: Sat, 17 Aug 2019 08:19:33 +0100
Message-ID: <CALQxJut_0bjojiFza9bZF26n0+9Vjq8QFqsxgd5Rxag+Qx609Q@mail.gmail.com> (raw)
In-Reply-To: <20190817033914.4812-1-hdanton@sina.com>

On Sat, 17 Aug 2019 at 04:39, Hillf Danton <hdanton@sina.com> wrote:
>
>
> On Thu, 15 Aug 2019 12:09:41 +0100 Tom Murphy wrote:
> >
> > Handle devices which defer their attach to the iommu in the dma-iommu api
> >
> > Signed-off-by: Tom Murphy <murphyt7@tcd.ie>
> > ---
> >  drivers/iommu/dma-iommu.c | 27 ++++++++++++++++++++++++++-
> >  1 file changed, 26 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> > index 2712fbc68b28..906b7fa14d3c 100644
> > --- a/drivers/iommu/dma-iommu.c
> > +++ b/drivers/iommu/dma-iommu.c
> > @@ -22,6 +22,7 @@
> >  #include <linux/pci.h>
> >  #include <linux/scatterlist.h>
> >  #include <linux/vmalloc.h>
> > +#include <linux/crash_dump.h>
> >
> >  struct iommu_dma_msi_page {
> >       struct list_head        list;
> > @@ -351,6 +352,21 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
> >       return iova_reserve_iommu_regions(dev, domain);
> >  }
> >
> > +static int handle_deferred_device(struct device *dev,
> > +     struct iommu_domain *domain)
> > +{
> > +     const struct iommu_ops *ops = domain->ops;
> > +
> > +     if (!is_kdump_kernel())
> > +             return 0;
> > +
> > +     if (unlikely(ops->is_attach_deferred &&
> > +             ops->is_attach_deferred(domain, dev)))
> > +             return iommu_attach_device(domain, dev);
> > +
> > +     return 0;
> > +}
> > +
> >  /**
> >   * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
> >   *                    page flags.
> > @@ -463,6 +479,9 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
> >       size_t iova_off = iova_offset(iovad, phys);
> >       dma_addr_t iova;
> >
> > +     if (unlikely(handle_deferred_device(dev, domain)))
> > +             return DMA_MAPPING_ERROR;
> > +
> >       size = iova_align(iovad, size + iova_off);
> >
> >       iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
>
> iommu_map_atomic() is applied to __iommu_dma_map() in 2/5.
> Is it an atomic context currently given the mutex_lock() in
> iommu_attach_device()?

I don't see your point here. __iommu_dma_map isn't called from
iommu_attach_device, why would we care about a mutex in
iommu_attach_device?

__iommu_dma_map can be called from an atomic context (it isn't always
but it does happen). __iommu_dma_map is called by iommu_dma_alloc
which implements the iommu_dma_ops::alloc function which by design
needs to be callable from an atomic context. Does that answer your
question?

>

  parent reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-15 11:09 [PATCH V5 0/5] iommu/amd: Convert the AMD iommu driver to the dma-iommu api Tom Murphy
2019-08-15 11:09 ` [PATCH V5 1/5] iommu/amd: Remove unnecessary locking from AMD iommu driver Tom Murphy
2019-08-20  9:41   ` Christoph Hellwig
2019-08-24  7:56     ` Tom Murphy
2019-08-24 22:41       ` Christoph Hellwig
2019-08-15 11:09 ` [PATCH V5 2/5] iommu: Add gfp parameter to iommu_ops::map Tom Murphy
2019-08-19 18:23   ` Robin Murphy
2019-08-20  9:41   ` Christoph Hellwig
2019-08-15 11:09 ` [PATCH V5 3/5] iommu/dma-iommu: Handle deferred devices Tom Murphy
2019-08-19 18:26   ` Robin Murphy
2019-08-20  9:43   ` Christoph Hellwig
2019-08-15 11:09 ` [PATCH V5 4/5] iommu/dma-iommu: Use the dev->coherent_dma_mask Tom Murphy
2019-08-19 18:39   ` Robin Murphy
2019-08-20  9:43   ` Christoph Hellwig
2019-08-15 11:09 ` [PATCH V5 5/5] iommu/amd: Convert AMD iommu driver to the dma-iommu api Tom Murphy
     [not found] ` <20190817033914.4812-1-hdanton@sina.com>
2019-08-17  7:19   ` Tom Murphy [this message]
2019-09-05  6:18 ` [PATCH V5 0/5] iommu/amd: Convert the " Christoph Hellwig

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CALQxJut_0bjojiFza9bZF26n0+9Vjq8QFqsxgd5Rxag+Qx609Q@mail.gmail.com \
    --to=murphyt7@tcd.ie \
    --cc=agross@kernel.org \
    --cc=dwmw2@infradead.org \
    --cc=gerald.schaefer@de.ibm.com \
    --cc=hdanton@sina.com \
    --cc=heiko@sntech.de \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jean-philippe@linaro.org \
    --cc=jonathanh@nvidia.com \
    --cc=joro@8bytes.org \
    --cc=kgene@kernel.org \
    --cc=krzk@kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-rockchip@lists.infradead.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=m.szyprowski@samsung.com \
    --cc=matthias.bgg@gmail.com \
    --cc=robdclark@gmail.com \
    --cc=robin.murphy@arm.com \
    --cc=thierry.reding@gmail.com \
    --cc=virtualization@lists.linux-foundation.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ARM-MSM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-msm/0 linux-arm-msm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-msm linux-arm-msm/ https://lore.kernel.org/linux-arm-msm \
		linux-arm-msm@vger.kernel.org
	public-inbox-index linux-arm-msm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-arm-msm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git