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Date:   Sat, 5 Oct 2019 10:40:33 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Kees Cook <keescook@chromium.org>
Cc:     Robin Murphy <robin.murphy@arm.com>,
        Laura Abbott <labbott@redhat.com>,
        linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Allison Randal <allison@lohutok.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Stephen Boyd <swboyd@chromium.org>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Semmle Security Reports <security-reports@semmle.com>,
        iommu@lists.linux-foundation.org
Subject: Re: [PATCH v2] dma-mapping: Move vmap address checks into
 dma_map_single()
Message-ID: <20191005084033.GA14801@lst.de>
References: <201910041420.F6E55D29A@keescook>
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Please split the usb and dma-mapping parts into separate patches.

> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 4a1c4fca475a..12dbd07f74f2 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -583,6 +583,13 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev)
>  static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
>  		size_t size, enum dma_data_direction dir, unsigned long attrs)
>  {
> +	/* DMA must never operate on areas that might be remapped. */
> +	if (WARN_ONCE(is_vmalloc_addr(ptr),
> +		      "%s %s: driver maps %lu bytes from vmalloc area\n",
> +		      dev ? dev_driver_string(dev) : "unknown driver",
> +		      dev ? dev_name(dev) : "unknown device", size))
> +		return DMA_MAPPING_ERROR;

a NULL device isn't supported any more, so we can remove the handling
for it here.