Patchwork [net-2.6] jme: Fix unmap error (Causing system freeze)

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Submitter Guo-Fu Tseng
Date July 21, 2011, 2:57 a.m.
Message ID <1311217056-9073-1-git-send-email-cooldavid@cooldavid.org>
Download mbox | patch
Permalink /patch/105878/
State Accepted
Delegated to: David Miller
Headers show

Comments

Guo-Fu Tseng - July 21, 2011, 2:57 a.m.
From: Guo-Fu Tseng <cooldavid@cooldavid.org>


This patch add the missing dma_unmap().
Which solved the critical issue of system freeze on heavy load.

Michal Miroslaw's rejected patch:
[PATCH v2 10/46] net: jme: convert to generic DMA API
Pointed out the issue also, thank you Michal.
But the fix was incorrect. It would unmap needed address
when low memory.

Got lots of feedback from End user and Gentoo Bugzilla.
https://bugs.gentoo.org/show_bug.cgi?id=373109
Thank you all. :)

Cc: stable@kernel.org
Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org>
---
 drivers/net/jme.c |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)
Chris Wright - July 21, 2011, 7:30 p.m.
* cooldavid@cooldavid.org (cooldavid@cooldavid.org) wrote:
> From: Guo-Fu Tseng <cooldavid@cooldavid.org>
> 
> This patch add the missing dma_unmap().
> Which solved the critical issue of system freeze on heavy load.
> 
> Michal Miroslaw's rejected patch:
> [PATCH v2 10/46] net: jme: convert to generic DMA API
> Pointed out the issue also, thank you Michal.
> But the fix was incorrect. It would unmap needed address
> when low memory.
> 
> Got lots of feedback from End user and Gentoo Bugzilla.
> https://bugs.gentoo.org/show_bug.cgi?id=373109
> Thank you all. :)

Also referred to in kernel bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=39312

> Cc: stable@kernel.org
> Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org>

Acked-by: Chris Wright <chrisw@sous-sol.org>
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David Miller - July 21, 2011, 10:23 p.m.
From: Chris Wright <chrisw@sous-sol.org>
Date: Thu, 21 Jul 2011 12:30:08 -0700

> * cooldavid@cooldavid.org (cooldavid@cooldavid.org) wrote:
>> From: Guo-Fu Tseng <cooldavid@cooldavid.org>
>> 
>> This patch add the missing dma_unmap().
>> Which solved the critical issue of system freeze on heavy load.
>> 
>> Michal Miroslaw's rejected patch:
>> [PATCH v2 10/46] net: jme: convert to generic DMA API
>> Pointed out the issue also, thank you Michal.
>> But the fix was incorrect. It would unmap needed address
>> when low memory.
>> 
>> Got lots of feedback from End user and Gentoo Bugzilla.
>> https://bugs.gentoo.org/show_bug.cgi?id=373109
>> Thank you all. :)
> 
> Also referred to in kernel bugzilla:
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=39312
> 
>> Cc: stable@kernel.org
>> Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org>
> 
> Acked-by: Chris Wright <chrisw@sous-sol.org>

Applied, but it's too late for 3.0 so I'll just submit it to all
the -stable branches after 3.0-final is released.

Thanks.
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=?ISO-8859-2?Q?Micha=B3_Miros=B3aw?= - July 22, 2011, 7:45 a.m.
2011/7/21  <cooldavid@cooldavid.org>:
> From: Guo-Fu Tseng <cooldavid@cooldavid.org>
>
> This patch add the missing dma_unmap().
> Which solved the critical issue of system freeze on heavy load.
>
> Michal Miroslaw's rejected patch:
> [PATCH v2 10/46] net: jme: convert to generic DMA API
> Pointed out the issue also, thank you Michal.
> But the fix was incorrect. It would unmap needed address
> when low memory.

My patch also fixed another issue - from correctness point of view,
you should not use virt_to_page+dma_map_page here, but dma_map_single.

Best Regards,
Michał Mirosław
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Patch

diff --git a/drivers/net/jme.c b/drivers/net/jme.c
index b5b174a..1973814 100644
--- a/drivers/net/jme.c
+++ b/drivers/net/jme.c
@@ -753,20 +753,28 @@  jme_make_new_rx_buf(struct jme_adapter *jme, int i)
 	struct jme_ring *rxring = &(jme->rxring[0]);
 	struct jme_buffer_info *rxbi = rxring->bufinf + i;
 	struct sk_buff *skb;
+	dma_addr_t mapping;
 
 	skb = netdev_alloc_skb(jme->dev,
 		jme->dev->mtu + RX_EXTRA_LEN);
 	if (unlikely(!skb))
 		return -ENOMEM;
 
+	mapping = pci_map_page(jme->pdev, virt_to_page(skb->data),
+			       offset_in_page(skb->data), skb_tailroom(skb),
+			       PCI_DMA_FROMDEVICE);
+	if (unlikely(pci_dma_mapping_error(jme->pdev, mapping))) {
+		dev_kfree_skb(skb);
+		return -ENOMEM;
+	}
+
+	if (likely(rxbi->mapping))
+		pci_unmap_page(jme->pdev, rxbi->mapping,
+			       rxbi->len, PCI_DMA_FROMDEVICE);
+
 	rxbi->skb = skb;
 	rxbi->len = skb_tailroom(skb);
-	rxbi->mapping = pci_map_page(jme->pdev,
-					virt_to_page(skb->data),
-					offset_in_page(skb->data),
-					rxbi->len,
-					PCI_DMA_FROMDEVICE);
-
+	rxbi->mapping = mapping;
 	return 0;
 }