linux-kernel - Re: [Linux-c6x-dev] [PATCH 3/9] c6x: Provide dma_mmap_coherent() and dma_get

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]

Date:	Tue, 15 Jan 2013 09:46:58 +0530
From:	Vineet Gupta <Vineet.Gupta1@...opsys.com>
To:	Mark Salter <msalter@...hat.com>
CC:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	<linux-arch@...r.kernel.org>, <linux-c6x-dev@...ux-c6x.org>,
	<linux-kernel@...r.kernel.org>,
	"Marek Szyprowski" <m.szyprowski@...sung.com>
Subject: Re: [Linux-c6x-dev] [PATCH 3/9] c6x: Provide dma_mmap_coherent()
 and dma_get_sgtable()

On Monday 14 January 2013 09:07 PM, Mark Salter wrote:
> On Sun, 2013-01-13 at 11:44 +0100, Geert Uytterhoeven wrote:
>> c6x/allmodconfig (assumed):
>>
>> drivers/media/v4l2-core/videobuf2-dma-contig.c: In function ‘vb2_dc_mmap’:
>> drivers/media/v4l2-core/videobuf2-dma-contig.c:204: error: implicit declaration of function ‘dma_mmap_coherent’
>> drivers/media/v4l2-core/videobuf2-dma-contig.c: In function ‘vb2_dc_get_base_sgt’:
>> drivers/media/v4l2-core/videobuf2-dma-contig.c:387: error: implicit declaration of function ‘dma_get_sgtable’
>>
>> For architectures using dma_map_ops, dma_mmap_coherent() and
>> dma_get_sgtable() are provided in <asm-generic/dma-mapping-common.h>.
>>
>> C6x does not use dma_map_ops, hence it should implement them as inline
>> stubs using dma_common_mmap() and dma_common_get_sgtable().
>>
> 
> So are dma_mmap_coherent() and dma_get_sgtable() part of the DMA API
> now? I don't them in Documentation/DMA*.txt anywhere.
> 
> Why does the default dma_common_mmap() for !CONFIG_MMU return an
> error?
> 
> Wouldn't it be better to provide default implementations that an arch
> could override rather than having to patch all "no dma_map_ops"
> architectures?
> 
> --Mark
> 
> 

Speaking for the still-reviewed ARC Port, I completely agree with Mark.

-Vineet
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/