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 V2 4/4] misc: vop: mapping kernel memory to user space as noncached
Date: Tue, 29 Sep 2020 11:28:33 +0100 [thread overview]
Message-ID: <20200929102833.GD7784@infradead.org> (raw)
In-Reply-To: <20200929084425.24052-5-sherry.sun@nxp.com>
On Tue, Sep 29, 2020 at 04:44:25PM +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 4d5feb39aeb7..6e193bd64ef1 100644
> --- a/drivers/misc/mic/vop/vop_vringh.c
> +++ b/drivers/misc/mic/vop/vop_vringh.c
> @@ -1057,7 +1057,7 @@ 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));
You can't call remap_pfn_range on memory returned from
dma_alloc_coherent (which btw is not marked uncached on many platforms).
You need to use the dma_mmap_coherent helper instead. And this also
needs to go into the first patch.
next prev parent reply other threads:[~2020-09-29 10:28 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 8:44 [PATCH V2 0/4] Change vring space from nomal memory to dma coherent memory Sherry Sun
2020-09-29 8:44 ` [PATCH V2 1/4] misc: vop: change the way of allocating vring Sherry Sun
2020-09-29 10:23 ` Christoph Hellwig
2020-09-29 13:02 ` Sherry Sun
2020-09-29 8:44 ` [PATCH V2 2/4] misc: vop: do not allocate and reassign the used ring Sherry Sun
2020-09-29 10:24 ` Christoph Hellwig
2020-09-29 13:02 ` Sherry Sun
2020-09-29 14:28 ` David Laight
2020-09-29 8:44 ` [PATCH V2 3/4] misc: vop: simply return the saved dma address instead of virt_to_phys Sherry Sun
2020-09-29 10:26 ` Christoph Hellwig
2020-09-29 13:10 ` Sherry Sun
2020-09-29 18:11 ` Christoph Hellwig
2020-09-30 7:30 ` Sherry Sun
2020-10-05 13:42 ` Christoph Hellwig
2020-09-29 8:44 ` [PATCH V2 4/4] misc: vop: mapping kernel memory to user space as noncached Sherry Sun
2020-09-29 10:28 ` Christoph Hellwig [this message]
2020-09-29 13:12 ` Sherry Sun
2020-09-29 15:39 ` David Laight
2020-10-13 2:02 ` Sherry Sun
2020-10-20 1:33 ` Sherry Sun
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