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Date: Fri, 2 Feb 2024 11:36:23 -0400
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Kevin Tian <kevin.tian@intel.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Nicolin Chen <nicolinc@nvidia.com>, Yi Liu <yi.l.liu@intel.com>,
	Jacob Pan <jacob.jun.pan@linux.intel.com>,
	Longfang Liu <liulongfang@huawei.com>,
	Yan Zhao <yan.y.zhao@intel.com>, iommu@lists.linux.dev,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 15/16] iommu: Make iopf_group_response() return void
Message-ID: <20240202153623.GA50608@ziepe.ca>
References: <20240122054308.23901-1-baolu.lu@linux.intel.com>
 <20240122054308.23901-16-baolu.lu@linux.intel.com>
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In-Reply-To: <20240122054308.23901-16-baolu.lu@linux.intel.com>

On Mon, Jan 22, 2024 at 01:43:07PM +0800, Lu Baolu wrote:
> The iopf_group_response() should return void, as nothing can do anything
> with the failure. This implies that ops->page_response() must also return
> void; this is consistent with what the drivers do. The failure paths,
> which are all integrity validations of the fault, should be WARN_ON'd,
> not return codes.
> 
> If the iommu core fails to enqueue the fault, it should respond the fault
> directly by calling ops->page_response() instead of returning an error
> number and relying on the iommu drivers to do so. Consolidate the error
> fault handling code in the core.
> 
> Co-developed-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  include/linux/iommu.h                       |  14 +--
>  drivers/iommu/intel/iommu.h                 |   4 +-
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  50 +++-----
>  drivers/iommu/intel/svm.c                   |  18 +--
>  drivers/iommu/io-pgfault.c                  | 132 +++++++++++---------
>  5 files changed, 99 insertions(+), 119 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

>  
> +static struct iopf_group *iopf_group_alloc(struct iommu_fault_param *iopf_param,
> +					   struct iopf_fault *evt,
> +					   struct iopf_group *abort_group)
> +{
> +	struct iopf_fault *iopf, *next;
> +	struct iopf_group *group;
> +
> +	group = kzalloc(sizeof(*group), GFP_KERNEL);
> +	if (!group) {
> +		/*
> +		 * We always need to construct the group as we need it to abort
> +		 * the request at the driver if it cfan't be handled.
                                                  ^^^^^^ can't


Jason