From: Jason Gunthorpe via iommu <iommu@lists.linux-foundation.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
iommu@lists.linux-foundation.org,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH RFC 10/11] iommu: Make IOPF handling framework generic
Date: Mon, 21 Mar 2022 09:50:21 -0300 [thread overview]
Message-ID: <20220321125021.GQ11336@nvidia.com> (raw)
In-Reply-To: <20220320064030.2936936-11-baolu.lu@linux.intel.com>
On Sun, Mar 20, 2022 at 02:40:29PM +0800, Lu Baolu wrote:
> +static enum iommu_page_response_code
> +iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
> +{
> + vm_fault_t ret;
> + struct mm_struct *mm;
> + struct vm_area_struct *vma;
> + unsigned int access_flags = 0;
> + struct iommu_domain *domain = data;
Why is the iommu_domain not passed in as a fully typed object? I would
think data should some opaque value used by non-sva cases.
What is the lifetime model here anyhow?
> + unsigned int fault_flags = FAULT_FLAG_REMOTE;
> + struct iommu_fault_page_request *prm = &fault->prm;
> + enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
> +
> + if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID))
> + return status;
> +
> + mm = domain->sva_cookie;
> + if (IS_ERR_OR_NULL(mm))
Do not use this function
Do not store err pointers in structs.
> +out_put_mm:
> + mmap_read_unlock(mm);
> + mmput(mm);
mm structs are weird, they have two refcounts.
The 'sva_cookie' should hold a mmgrab/mmdrop() refcount to keep the
pointer alive but to touch the mmap lock you have to upgrade it to a
refcount that prevents destruction using mmget_not_zero() just for
this short period.
Jason
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next prev parent reply other threads:[~2022-03-21 12:50 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-20 6:40 [PATCH RFC 00/11] iommu: SVA and IOPF refactoring Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 01/11] iommu: Add pasid_bits field in struct dev_iommu Lu Baolu
2022-03-21 7:01 ` Tian, Kevin
2022-03-21 10:22 ` Lu Baolu
2022-03-22 0:26 ` Tian, Kevin
2022-03-22 0:48 ` Lu Baolu
2022-03-21 11:22 ` Jean-Philippe Brucker
2022-03-22 0:45 ` Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 02/11] iommu: Add iommu_domain type for SVA Lu Baolu
2022-03-21 7:06 ` Tian, Kevin
2022-03-21 10:23 ` Lu Baolu
2022-03-21 11:47 ` Jason Gunthorpe via iommu
2022-03-22 0:54 ` Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 03/11] iommu: Add attach/detach_dev_pasid domain ops Lu Baolu
2022-03-21 7:13 ` Tian, Kevin
2022-03-21 10:27 ` Lu Baolu
2022-03-21 11:53 ` Jason Gunthorpe via iommu
2022-03-20 6:40 ` [PATCH RFC 04/11] iommu/vt-d: Add SVA domain support Lu Baolu
2022-03-21 7:45 ` Tian, Kevin
2022-03-21 10:37 ` Lu Baolu
2022-03-21 11:56 ` Jason Gunthorpe via iommu
2022-03-22 4:25 ` Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 05/11] arm-smmu-v3/sva: " Lu Baolu
2022-03-21 11:31 ` Jean-Philippe Brucker
2022-03-21 11:58 ` Jason Gunthorpe via iommu
2022-03-20 6:40 ` [PATCH RFC 06/11] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces Lu Baolu
2022-03-21 8:04 ` Tian, Kevin
2022-03-21 11:01 ` Lu Baolu
2022-03-21 12:03 ` Jason Gunthorpe via iommu
2022-03-21 11:33 ` Jean-Philippe Brucker
2022-03-22 4:29 ` Lu Baolu
2022-03-21 12:05 ` Jason Gunthorpe via iommu
2022-03-22 4:31 ` Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 07/11] iommu: Remove SVA related callbacks from iommu ops Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 08/11] iommu: Handle IO page faults directly Lu Baolu
2022-03-21 11:35 ` Jean-Philippe Brucker
2022-03-22 0:39 ` Tian, Kevin
2022-03-20 6:40 ` [PATCH RFC 09/11] iommu: Add iommu_get_domain_for_dev_pasid() Lu Baolu
2022-03-21 12:40 ` Jason Gunthorpe via iommu
2022-03-22 4:50 ` Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 10/11] iommu: Make IOPF handling framework generic Lu Baolu
2022-03-21 8:09 ` Tian, Kevin
2022-03-21 11:42 ` Jean-Philippe Brucker
2022-03-21 12:43 ` Jason Gunthorpe via iommu
2022-03-22 5:03 ` Lu Baolu
2022-03-22 10:02 ` Jean-Philippe Brucker
2022-03-22 12:15 ` Jason Gunthorpe via iommu
2022-03-22 1:00 ` Tian, Kevin
2022-03-22 10:06 ` Jean-Philippe Brucker
2022-03-22 10:24 ` Tian, Kevin
2022-03-22 10:50 ` Jean-Philippe Brucker
2022-03-21 11:39 ` Jean-Philippe Brucker
2022-03-22 5:28 ` Lu Baolu
2022-03-21 12:50 ` Jason Gunthorpe via iommu [this message]
2022-03-22 5:48 ` Lu Baolu
2022-03-20 6:40 ` [PATCH RFC 11/11] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu
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