Re: dma-debug report/error on natsemi eth0

[FUJITA Tomonori]

On Thu, 30 Jun 2011 12:34:52 -0600
Jim Cromie <jim.cromie@xxxxxxxxx> wrote:

> since adding DMA-debug to my config, Ive been seeing these.
> I suspect it goes back a ways..
> 
> its on my list to do some investigating,
> but I figured Id report in the meantime.
> 
> ------------[ cut here ]------------
> WARNING: at /home/jimc/projects/lx/linux-2.6/lib/dma-debug.c:820
> check_unmap+0x1fe/0x56a()
> natsemi 0000:00:06.0: DMA-API: device driver frees DMA memory with
> different size [device address=0x0000000006ef0040] [map size=1538
> bytes] [unmap size=1522 bytes]
> Modules linked in: pc8736x_gpio pc87360 hwmon_vid scx200_gpio nsc_gpio
> scx200_hrt scx200_acb i2c_core arc4 rtl8180 mac80211 eeprom_93cx6
> cfg80211 pcspkr rfkill scx200 ide_gd_mod ide_pci_generic ohci_hcd
> usbcore sc1200 ide_core
> Pid: 870, comm: collector Not tainted 3.0.0-rc5-sk-00080-gca56a95 #1
> Call Trace:
>  [<c011a556>] warn_slowpath_common+0x4a/0x5f
>  [<c02565cb>] ? check_unmap+0x1fe/0x56a
>  [<c011a5cf>] warn_slowpath_fmt+0x26/0x2a

The following patch silences the warning?

diff --git a/drivers/net/natsemi.c b/drivers/net/natsemi.c
index b78be08..1019379 100644
--- a/drivers/net/natsemi.c
+++ b/drivers/net/natsemi.c
@@ -2360,7 +2360,8 @@ static void netdev_rx(struct net_device *dev, int *work_done, int work_to_do)
 					PCI_DMA_FROMDEVICE);
 			} else {
 				pci_unmap_single(np->pci_dev, np->rx_dma[entry],
-					buflen, PCI_DMA_FROMDEVICE);
+						 buflen+NATSEMI_PADDING,
+						 PCI_DMA_FROMDEVICE);
 				skb_put(skb = np->rx_skbuff[entry], pkt_len);
 				np->rx_skbuff[entry] = NULL;
 			}
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