linux-kernel - Re: [PATCH v2 12/24] iommu/dma: Unexport IOVA cookie management

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Date:   Fri, 30 Jul 2021 14:07:42 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Robin Murphy <robin.murphy@....com>, joro@...tes.org,
        will@...nel.org
Cc:     baolu.lu@...ux.intel.com, iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        suravee.suthikulpanit@....com, john.garry@...wei.com,
        dianders@...omium.org
Subject: Re: [PATCH v2 12/24] iommu/dma: Unexport IOVA cookie management

On 7/28/21 11:58 PM, Robin Murphy wrote:
> IOVA cookies are now got and put by core code, so we no longer need to
> export these to modular drivers. The export for getting MSI cookies
> stays, since VFIO can still be a module, but it was already relying on
> someone else putting them, so that aspect is unaffected.
> 
> Signed-off-by: Robin Murphy <robin.murphy@....com>
> ---
>   drivers/iommu/dma-iommu.c | 7 -------
>   drivers/iommu/iommu.c     | 3 +--
>   2 files changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 98ba927aee1a..10067fbc4309 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -98,9 +98,6 @@ static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type)
>   /**
>    * iommu_get_dma_cookie - Acquire DMA-API resources for a domain
>    * @domain: IOMMU domain to prepare for DMA-API usage
> - *
> - * IOMMU drivers should normally call this from their domain_alloc
> - * callback when domain->type == IOMMU_DOMAIN_DMA.
>    */
>   int iommu_get_dma_cookie(struct iommu_domain *domain)
>   {
> @@ -113,7 +110,6 @@ int iommu_get_dma_cookie(struct iommu_domain *domain)
>   
>   	return 0;
>   }
> -EXPORT_SYMBOL(iommu_get_dma_cookie);
>   
>   /**
>    * iommu_get_msi_cookie - Acquire just MSI remapping resources
> @@ -151,8 +147,6 @@ EXPORT_SYMBOL(iommu_get_msi_cookie);
>    * iommu_put_dma_cookie - Release a domain's DMA mapping resources
>    * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() or
>    *          iommu_get_msi_cookie()
> - *
> - * IOMMU drivers should normally call this from their domain_free callback.
>    */
>   void iommu_put_dma_cookie(struct iommu_domain *domain)
>   {
> @@ -172,7 +166,6 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
>   	kfree(cookie);
>   	domain->iova_cookie = NULL;
>   }
> -EXPORT_SYMBOL(iommu_put_dma_cookie);
>   
>   /**
>    * iommu_dma_get_resv_regions - Reserved region driver helper
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index ea5a9ea8d431..fa8109369f74 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1947,8 +1947,7 @@ static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
>   	/* Assume all sizes by default; the driver may override this later */
>   	domain->pgsize_bitmap  = bus->iommu_ops->pgsize_bitmap;
>   
> -	/* Temporarily ignore -EEXIST while drivers still get their own cookies */
> -	if (type == IOMMU_DOMAIN_DMA && iommu_get_dma_cookie(domain) == -ENOMEM) {
> +	if (type == IOMMU_DOMAIN_DMA && iommu_get_dma_cookie(domain)) {
>   		iommu_domain_free(domain);
>   		domain = NULL;
>   	}
> 


Reviewed-by: Lu Baolu <baolu.lu@...ux.intel.com>

Best regards,
baolu