From: "David S. Miller" <davem@redhat.com>
To: Pekka Pietikainen <pp@ee.oulu.fi>
Cc: jgarzik@pobox.com, jolt@tuxbox.org, linux-kernel@vger.kernel.org,
netdev@oss.sgi.com
Subject: Re: [PATCH] b44 1GB DMA workaround (was: b44: add 47xx support)
Date: Tue, 3 Aug 2004 18:39:19 -0700 [thread overview]
Message-ID: <20040803183919.2990d045.davem@redhat.com> (raw)
In-Reply-To: <20040804003108.GA10445@ee.oulu.fi>
On Wed, 4 Aug 2004 03:31:08 +0300
Pekka Pietikainen <pp@ee.oulu.fi> wrote:
> + if(mapping+len > B44_DMA_MASK) {
> + /* Chip can't handle DMA to/from >1GB, use bounce buffer */
> + pci_unmap_single(bp->pdev, mapping, len,PCI_DMA_TODEVICE);
> + memcpy(bp->tx_bufs+entry*TX_PKT_BUF_SZ,skb->data,skb->len);
> + skb->data=bp->tx_bufs+entry*TX_PKT_BUF_SZ;
> + mapping = pci_map_single(bp->pdev, skb->data, len, PCI_DMA_TODEVICE);
> + }
Changing skb->data is not legal. Please implement this in
such a way that skb->data does not get modified. By modifying
skb->data you will break things such as packet sniffers and
netfilter, and that's just the tip of the iceberg. :-)
I would suggest merely freeing up this TX skb, and marking the
entry in the b44 software state with some dummy skb pointer
such as (void *) 0x1UL or something like that to indicate
this case.
next prev parent reply other threads:[~2004-08-04 1:39 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-23 21:35 b44: add 47xx support Florian Schirmer
2004-07-26 14:11 ` Pekka Pietikainen
2004-08-04 0:31 ` [PATCH] b44 1GB DMA workaround (was: b44: add 47xx support) Pekka Pietikainen
2004-08-04 1:39 ` David S. Miller [this message]
2004-08-07 22:40 ` Pekka Pietikainen
2004-08-08 0:05 ` David S. Miller
2004-08-08 9:31 ` [PATCH] b44 1GB DMA workaround Pekka Pietikainen
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