From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Christoph Hellwig <hch@infradead.org>
Cc: yvahkhfo.1df7f8c2@hashmail.org, security@kernel.org,
linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: usb zero copy dma handling
Date: Thu, 8 Aug 2019 17:57:34 +0100 [thread overview]
Message-ID: <20190808165734.GG5193@shell.armlinux.org.uk> (raw)
In-Reply-To: <20190808161015.GA8470@infradead.org>
On Thu, Aug 08, 2019 at 09:10:15AM -0700, Christoph Hellwig wrote:
> 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.
So what if usbm->mem is from kmalloc because the host doesn't support DMA?
--
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prev parent reply other threads:[~2019-08-08 16:57 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
2019-08-08 16:12 ` Christoph Hellwig
2019-08-08 16:57 ` Russell King - ARM Linux admin [this message]
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