linux-kernel - Re: [PATCH 1/2] dma-coherent: remove the DMA_MEMORY_INCLUDES

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <dc11c20a-4801-0a1a-9301-9a209bf225b3@arm.com>
Date:   Wed, 28 Jun 2017 15:34:05 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Christoph Hellwig <hch@....de>, linux-kernel@...r.kernel.org,
        m.szyprowski@...sung.com
Subject: Re: [PATCH 1/2] dma-coherent: remove the DMA_MEMORY_INCLUDES_CHILDREN
 flag

On 27/06/17 21:17, Christoph Hellwig wrote:
> This flag was never implemented or used.

And at worst, we can always bring it back.

Reviewed-by: Robin Murphy <robin.murphy@....com>

> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
>  Documentation/DMA-API.txt     | 4 ----
>  drivers/base/dma-coherent.c   | 2 --
>  drivers/char/virtio_console.c | 3 ---
>  include/linux/dma-mapping.h   | 3 +--
>  4 files changed, 1 insertion(+), 11 deletions(-)
> 
> diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
> index 6b20128fab8a..03072bc7ff74 100644
> --- a/Documentation/DMA-API.txt
> +++ b/Documentation/DMA-API.txt
> @@ -524,10 +524,6 @@ dma_alloc_coherent() be addressable using read()/write()/memcpy_toio() etc.
>  
>  One or both of these flags must be present.
>  
> -DMA_MEMORY_INCLUDES_CHILDREN - make the declared memory be allocated by
> -dma_alloc_coherent of any child devices of this one (for memory residing
> -on a bridge).
> -
>  DMA_MEMORY_EXCLUSIVE - only allocate memory from the declared regions. 
>  Do not allow dma_alloc_coherent() to fall back to system memory when
>  it's out of memory in the declared region.
> diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
> index 2ae24c28e70c..e70e33d5c902 100644
> --- a/drivers/base/dma-coherent.c
> +++ b/drivers/base/dma-coherent.c
> @@ -109,8 +109,6 @@ static int dma_assign_coherent_memory(struct device *dev,
>  		return -EBUSY;
>  
>  	dev->dma_mem = mem;
> -	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
> -
>  	return 0;
>  }
>  
> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> index ad843eb02ae7..48e86ce9fac8 100644
> --- a/drivers/char/virtio_console.c
> +++ b/drivers/char/virtio_console.c
> @@ -451,9 +451,6 @@ static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
>  		 * device is created by remoteproc, the DMA memory is
>  		 * associated with the grandparent device:
>  		 * vdev => rproc => platform-dev.
> -		 * The code here would have been less quirky if
> -		 * DMA_MEMORY_INCLUDES_CHILDREN had been supported
> -		 * in dma-coherent.c
>  		 */
>  		if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent)
>  			goto free_buf;
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 843ab866e0f4..fb66fe98e61d 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -685,8 +685,7 @@ static inline int dma_get_cache_alignment(void)
>  /* flags for the coherent memory api */
>  #define	DMA_MEMORY_MAP			0x01
>  #define DMA_MEMORY_IO			0x02
> -#define DMA_MEMORY_INCLUDES_CHILDREN	0x04
> -#define DMA_MEMORY_EXCLUSIVE		0x08
> +#define DMA_MEMORY_EXCLUSIVE		0x04
>  
>  #ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT
>  int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
>