From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: devicetree@vger.kernel.org, kevin.tian@intel.com, jgg@ziepe.ca,
linux-pci@vger.kernel.org, robin.murphy@arm.com,
fenghua.yu@intel.com, hch@infradead.org, linux-mm@kvack.org,
iommu@lists.linux-foundation.org, zhangfei.gao@linaro.org,
catalin.marinas@arm.com, felix.kuehling@amd.com, will@kernel.org,
christian.koenig@amd.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v6 02/25] iommu/ioasid: Add ioasid references
Date: Mon, 4 May 2020 08:22:54 -0700 [thread overview]
Message-ID: <20200504082254.58fc6365@jacob-builder> (raw)
In-Reply-To: <20200504143932.GC170104@myrica>
On Mon, 4 May 2020 16:39:32 +0200
Jean-Philippe Brucker <jean-philippe@linaro.org> wrote:
> On Thu, Apr 30, 2020 at 01:48:42PM -0700, Jacob Pan wrote:
> > On Thu, 30 Apr 2020 11:39:31 -0700
> > Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:
> >
> > > > -void ioasid_free(ioasid_t ioasid)
> > > > +bool ioasid_free(ioasid_t ioasid)
> > > > {
> > Sorry I missed this in the last reply.
> >
> > I think free needs to be unconditional since there is not a good
> > way to fail it.
> >
> > Also can we have more symmetric APIs, seems we don't have
> > ioasid_put() in this patchset.
>
> Yes I was thinking of renaming ioasid_free() to ioasid_put() but got
> lazy.
>
> > How about?
> > ioasid_alloc()
> > ioasid_free(); //drop reference, mark inactive, but not reclaimed if
> > refcount is not zero.
> > ioasid_get() // returns err if the ioasid is marked inactive by
> > ioasid_free()
>
> How does the caller know that the ioasid is in active/inactive state,
> and not freed/reallocated?
>
In inactive state, callers of ioasid_find(), ioasid_get() would all
fail. Only ioasid_put can still operate on it.
In freed state (i.e. not allocated), it will be the same as above with
the exception that ioasid_put has no effect.
> > ioasid_put();// drop reference, reclaim if refcount is 0.
>
> I'll add ioasid_put() for now. I'd like to avoid introducing the
> inactive state in this patch,
Sounds good. I just wanted to consult with you about the above APIs. I
will introduce the state when we have a real use.
> so shall I change the calls in the
> Intel driver to ioasid_put(), and not introduce a new ioasid_free()
> for the moment?
>
Sounds good.
> Thanks,
> Jean
>
[Jacob Pan]
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next prev parent reply other threads:[~2020-05-04 15:16 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 14:33 [PATCH v6 00/25] iommu: Shared Virtual Addressing for SMMUv3 Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 01/25] mm: Add a PASID field to mm_struct Jean-Philippe Brucker
2020-05-04 1:52 ` Xu Zaibo
2020-05-04 16:29 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 02/25] iommu/ioasid: Add ioasid references Jean-Philippe Brucker
2020-04-30 18:39 ` Jacob Pan
2020-04-30 20:48 ` Jacob Pan
2020-05-04 14:39 ` Jean-Philippe Brucker
2020-05-04 15:22 ` Jacob Pan [this message]
2020-05-04 14:25 ` Jean-Philippe Brucker
2020-05-04 15:27 ` Jacob Pan
2020-04-30 14:34 ` [PATCH v6 03/25] iommu/sva: Add PASID helpers Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 04/25] iommu: Add a page fault handler Jean-Philippe Brucker
2020-05-03 5:49 ` Lu Baolu
2020-05-04 16:22 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 05/25] iommu/iopf: Handle mm faults Jean-Philippe Brucker
2020-05-03 5:54 ` Lu Baolu
2020-05-04 16:25 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 06/25] arm64: mm: Add asid_gen_match() helper Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 07/25] arm64: mm: Pin down ASIDs for sharing mm with devices Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 08/25] iommu/io-pgtable-arm: Move some definitions to a header Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 09/25] iommu/arm-smmu-v3: Manage ASIDs with xarray Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 10/25] arm64: cpufeature: Export symbol read_sanitised_ftr_reg() Jean-Philippe Brucker
2020-04-30 15:18 ` Suzuki K Poulose
2020-04-30 14:34 ` [PATCH v6 11/25] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2020-04-30 15:39 ` Suzuki K Poulose
2020-05-04 14:11 ` Jean-Philippe Brucker
2020-05-04 14:42 ` Suzuki K Poulose
2020-04-30 14:34 ` [PATCH v6 12/25] iommu/arm-smmu-v3: Seize private ASID Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 13/25] iommu/arm-smmu-v3: Add support for VHE Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 14/25] iommu/arm-smmu-v3: Enable broadcast TLB maintenance Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 15/25] iommu/arm-smmu-v3: Add SVA feature checking Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 16/25] iommu/arm-smmu-v3: Add SVA device feature Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 17/25] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind() Jean-Philippe Brucker
2020-04-30 21:16 ` Jacob Pan
2020-05-04 16:43 ` Jean-Philippe Brucker
2020-05-04 20:47 ` Jacob Pan
2020-05-05 9:15 ` Jean-Philippe Brucker
2020-05-07 16:31 ` Jacob Pan
2020-05-01 12:15 ` Christoph Hellwig
2020-05-01 12:55 ` Jason Gunthorpe
2020-05-04 16:07 ` Jean-Philippe Brucker
2020-05-04 16:06 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 18/25] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 19/25] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update Jean-Philippe Brucker
2020-05-04 14:24 ` Prabhakar Kushwaha
2020-05-04 16:35 ` Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 20/25] iommu/arm-smmu-v3: Maintain a SID->device structure Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 21/25] dt-bindings: document stall property for IOMMU masters Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 22/25] iommu/arm-smmu-v3: Add stall support for platform devices Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 23/25] PCI/ATS: Add PRI stubs Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 24/25] PCI/ATS: Export PRI functions Jean-Philippe Brucker
2020-04-30 14:34 ` [PATCH v6 25/25] iommu/arm-smmu-v3: Add support for PRI Jean-Philippe Brucker
2020-04-30 21:18 ` [PATCH v6 00/25] iommu: Shared Virtual Addressing for SMMUv3 Jacob Pan
2020-05-04 15:09 ` Jean-Philippe Brucker
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