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From: Ezequiel Garcia <ezequiel.garcia@free-electrons•com>
To: David Miller <davem@davemloft•net>,
	Russell King <linux@arm•linux.org.uk>
Cc: netdev@vger•kernel.org, B38611@freescale•com,
	fabio.estevam@freescale•com, David.Laight@ACULAB•COM
Subject: Re: [PATCH v3] net: mv643xx_eth: Fix highmem support in non-TSO egress path
Date: Sat, 24 Jan 2015 10:45:29 -0300	[thread overview]
Message-ID: <54C3A1F9.1000403@free-electrons.com> (raw)
In-Reply-To: <1421937182-1708-1-git-send-email-ezequiel.garcia@free-electrons.com>

Hi all,

On 01/22/2015 11:33 AM, Ezequiel Garcia wrote:
> Commit 69ad0dd7af22b61d9e0e68e56b6290121618b0fb
> Author: Ezequiel Garcia <ezequiel.garcia@free-electrons•com>
> Date:   Mon May 19 13:59:59 2014 -0300
> 
>     net: mv643xx_eth: Use dma_map_single() to map the skb fragments
> 
> caused a nasty regression by removing the support for highmem skb
> fragments. By using page_address() to get the address of a fragment's
> page, we are assuming a lowmem page. However, such assumption is incorrect,
> as fragments can be in highmem pages, resulting in very nasty issues.
> 
> This commit fixes this by using the skb_frag_dma_map() helper,
> which takes care of mapping the skb fragment properly. Additionally,
> the type of mapping is now tracked, so it can be unmapped using
> dma_unmap_page or dma_unmap_single when appropriate.
> 
> This commit also fixes the error path in txq_init() to release the
> resources properly.
> 
> Fixes: 69ad0dd7af22 ("net: mv643xx_eth: Use dma_map_single() to map the skb fragments")
> Reported-by: Russell King <rmk+kernel@arm•linux.org.uk>

Russell, when you have some time, please test this patch. I think it
solves the regression and it manages to unmap the descriptors properly.

Thanks!
-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com

  reply	other threads:[~2015-01-24 13:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-22 12:14 [PATCH v2] net: mv643xx_eth: Fix highmem support in non-TSO egress path Ezequiel Garcia
2015-01-22 12:40 ` David Laight
2015-01-22 13:26   ` Ezequiel Garcia
2015-01-22 14:33 ` [PATCH v3] " Ezequiel Garcia
2015-01-24 13:45   ` Ezequiel Garcia [this message]
2015-01-26 23:11     ` Russell King - ARM Linux
2015-01-27  0:15   ` David Miller

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