From: Christoph Hellwig <hch@infradead.org>
To: Sherry Sun <sherry.sun@nxp.com>
Cc: hch@infradead.org, sudeep.dutt@intel.com,
ashutosh.dixit@intel.com, arnd@arndb.de,
gregkh@linuxfoundation.org, kishon@ti.com,
lorenzo.pieralisi@arm.com, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, linux-imx@nxp.com
Subject: Re: [PATCH V3 4/4] misc: vop: mapping kernel memory to user space as noncached
Date: Fri, 23 Oct 2020 10:28:37 +0100 [thread overview]
Message-ID: <20201023092837.GC29066@infradead.org> (raw)
In-Reply-To: <20201022050638.29641-5-sherry.sun@nxp.com>
On Thu, Oct 22, 2020 at 01:06:38PM +0800, Sherry Sun wrote:
> Mapping kernel space memory to user space as noncached, since user space
> need check the updates of avail_idx and device page flags timely.
>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> ---
> drivers/misc/mic/vop/vop_vringh.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/misc/mic/vop/vop_vringh.c b/drivers/misc/mic/vop/vop_vringh.c
> index b5612183dcb8..b75c2b713a3b 100644
> --- a/drivers/misc/mic/vop/vop_vringh.c
> +++ b/drivers/misc/mic/vop/vop_vringh.c
> @@ -1058,7 +1058,7 @@ static int vop_mmap(struct file *f, struct vm_area_struct *vma)
> }
> err = remap_pfn_range(vma, vma->vm_start + offset,
> pa >> PAGE_SHIFT, size,
> - vma->vm_page_prot);
> + pgprot_noncached(vma->vm_page_prot));
Again, memory allocated using dma_alloc_coherent can only be mapped
using dma_mmap_coherent, which will use the right attributes for the
mapping, which often are cached.
prev parent reply other threads:[~2020-10-23 9:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 5:06 [PATCH V3 0/4] Change vring space from nomal memory to dma coherent memory Sherry Sun
2020-10-22 5:06 ` [PATCH V3 1/4] misc: vop: change the way of allocating vring and device page Sherry Sun
2020-10-22 7:58 ` kernel test robot
2020-10-23 9:25 ` Christoph Hellwig
2020-10-26 2:54 ` Sherry Sun
2020-10-22 5:06 ` [PATCH V3 2/4] misc: vop: do not allocate and reassign the used ring Sherry Sun
2020-10-22 8:53 ` kernel test robot
2020-10-23 9:26 ` Christoph Hellwig
2020-10-26 3:04 ` Sherry Sun
2020-10-27 6:28 ` gregkh
2020-10-22 5:06 ` [PATCH V3 3/4] misc: vop: simply return the saved dma address instead of virt_to_phys Sherry Sun
2020-10-22 5:06 ` [PATCH V3 4/4] misc: vop: mapping kernel memory to user space as noncached Sherry Sun
2020-10-23 9:28 ` Christoph Hellwig [this message]
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