linux-kernel - Re: [PATCH v3 01/25] iommu: Pull IOVA cookie management into the core

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Message-ID: <6bfafe1c-fc8f-8836-fb80-c6a61788ddc8@samsung.com>
Date:   Thu, 5 Aug 2021 09:18:50 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Robin Murphy <robin.murphy@....com>, joro@...tes.org,
        will@...nel.org
Cc:     iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        suravee.suthikulpanit@....com, baolu.lu@...ux.intel.com,
        john.garry@...wei.com, dianders@...omium.org, rajatja@...gle.com,
        chenxiang66@...ilicon.com,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Yong Wu <yong.wu@...iatek.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Chunyan Zhang <chunyan.zhang@...soc.com>,
        Maxime Ripard <mripard@...nel.org>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>
Subject: Re: [PATCH v3 01/25] iommu: Pull IOVA cookie management into the
 core


On 04.08.2021 19:15, Robin Murphy wrote:
> Now that everyone has converged on iommu-dma for IOMMU_DOMAIN_DMA
> support, we can abandon the notion of drivers being responsible for the
> cookie type, and consolidate all the management into the core code.
>
> CC: Marek Szyprowski <m.szyprowski@...sung.com>
> CC: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> CC: Geert Uytterhoeven <geert+renesas@...der.be>
> CC: Yong Wu <yong.wu@...iatek.com>
> CC: Heiko Stuebner <heiko@...ech.de>
> CC: Chunyan Zhang <chunyan.zhang@...soc.com>
> CC: Maxime Ripard <mripard@...nel.org>
> Reviewed-by: Jean-Philippe Brucker <jean-philippe@...aro.org>
> Reviewed-by: Lu Baolu <baolu.lu@...ux.intel.com>
> Signed-off-by: Robin Murphy <robin.murphy@....com>
Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
>
> ---
>
> v3: Use a simpler temporary check instead of trying to be clever with
>      the error code
> ---
>   drivers/iommu/iommu.c | 7 +++++++
>   include/linux/iommu.h | 3 ++-
>   2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index f2cda9950bd5..b65fcc66ffa4 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -7,6 +7,7 @@
>   #define pr_fmt(fmt)    "iommu: " fmt
>   
>   #include <linux/device.h>
> +#include <linux/dma-iommu.h>
>   #include <linux/kernel.h>
>   #include <linux/bits.h>
>   #include <linux/bug.h>
> @@ -1946,6 +1947,11 @@ 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 avoid -EEXIST while drivers still get their own cookies */
> +	if (type == IOMMU_DOMAIN_DMA && !domain->iova_cookie && iommu_get_dma_cookie(domain)) {
> +		iommu_domain_free(domain);
> +		domain = NULL;
> +	}
>   	return domain;
>   }
>   
> @@ -1957,6 +1963,7 @@ EXPORT_SYMBOL_GPL(iommu_domain_alloc);
>   
>   void iommu_domain_free(struct iommu_domain *domain)
>   {
> +	iommu_put_dma_cookie(domain);
>   	domain->ops->domain_free(domain);
>   }
>   EXPORT_SYMBOL_GPL(iommu_domain_free);
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 4997c78e2670..141779d76035 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -40,6 +40,7 @@ struct iommu_domain;
>   struct notifier_block;
>   struct iommu_sva;
>   struct iommu_fault_event;
> +struct iommu_dma_cookie;
>   
>   /* iommu fault flags */
>   #define IOMMU_FAULT_READ	0x0
> @@ -86,7 +87,7 @@ struct iommu_domain {
>   	iommu_fault_handler_t handler;
>   	void *handler_token;
>   	struct iommu_domain_geometry geometry;
> -	void *iova_cookie;
> +	struct iommu_dma_cookie *iova_cookie;
>   };
>   
>   enum iommu_cap {

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland