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Date:   Fri, 30 Jul 2021 11:32:02 +0200
From:   Jean-Philippe Brucker <jean-philippe@linaro.org>
To:     Robin Murphy <robin.murphy@arm.com>
Cc:     joro@8bytes.org, will@kernel.org,
        Maxime Ripard <mripard@kernel.org>,
        Heiko Stuebner <heiko@sntech.de>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        linux-kernel@vger.kernel.org,
        Chunyan Zhang <chunyan.zhang@unisoc.com>,
        dianders@chromium.org, iommu@lists.linux-foundation.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 01/24] iommu: Pull IOVA cookie management into the core
Message-ID: <YQPHEpWLN3lZ92fp@myrica>
References: <cover.1627468308.git.robin.murphy@arm.com>
 <fcd58f6e0265b5339091cbabdea88151d437ad40.1627468309.git.robin.murphy@arm.com>
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On Wed, Jul 28, 2021 at 04:58:22PM +0100, 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@samsung.com>
> CC: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> CC: Geert Uytterhoeven <geert+renesas@glider.be>
> CC: Yong Wu <yong.wu@mediatek.com>
> CC: Heiko Stuebner <heiko@sntech.de>
> CC: Chunyan Zhang <chunyan.zhang@unisoc.com>
> CC: Chunyan Zhang <chunyan.zhang@unisoc.com>
> CC: Maxime Ripard <mripard@kernel.org>
> CC: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>

Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

> ---
>  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..ea5a9ea8d431 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 ignore -EEXIST while drivers still get their own cookies */
> +	if (type == IOMMU_DOMAIN_DMA && iommu_get_dma_cookie(domain) == -ENOMEM) {
> +		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 {
> -- 
> 2.25.1
> 
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