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From: Christoph Hellwig <hch@infradead.org>
To: yvahkhfo.1df7f8c2@hashmail.org
Cc: linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	security@kernel.org
Subject: Re: usb zero copy dma handling
Date: Thu, 8 Aug 2019 09:10:15 -0700	[thread overview]
Message-ID: <20190808161015.GA8470@infradead.org> (raw)
In-Reply-To: <20190808084636.GB15080@priv-mua.localdomain>

On Thu, Aug 08, 2019 at 10:46:36AM +0200, yvahkhfo.1df7f8c2@hashmail.org wrote:
> --- a/drivers/usb/core/devio.c
> +++ b/drivers/usb/core/devio.c
> @@ -238,9 +238,14 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
>  	usbm->vma_use_count = 1;
>  	INIT_LIST_HEAD(&usbm->memlist);
>  
> +#ifdef CONFIG_X86
>  	if (remap_pfn_range(vma, vma->vm_start,
>  			virt_to_phys(usbm->mem) >> PAGE_SHIFT,
>  			size, vma->vm_page_prot) < 0) {
> +#else /* !CONFIG_X86 */
> +	if (dma_mmap_coherent(ps->dev->bus->sysdev, 
> +			vma, mem, dma_handle, size) < 0) {
> +#endif /* !CONFIG_X86 */

Doing the dma_mmap_coherent unconditionally is the right thing here.
Gavin who is on Cc has been looking into that.

Note that you'll also need this patch which I'm going to send to Linus
this week before it properly works on x86:

http://git.infradead.org/users/hch/dma-mapping.git/commitdiff/197b3e665b82c6027be5c68a143233df7ce5224f

  parent reply	other threads:[~2019-08-08 16:10 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-08  8:46 usb zero copy dma handling yvahkhfo.1df7f8c2
2019-08-08  8:58 ` Greg KH
2019-08-08  9:46   ` Robin Murphy
2019-08-08 10:07     ` Greg KH
2019-08-08 10:43       ` Robin Murphy
2019-08-08 13:05       ` Greg KH
2019-08-08  9:59   ` Russell King - ARM Linux admin
2019-08-08 10:02     ` Oliver Neukum
2019-08-08 16:10 ` Christoph Hellwig [this message]
2019-08-08 16:12   ` Christoph Hellwig
2019-08-08 16:57   ` Russell King - ARM Linux admin

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