[PATCH] libertas: make if_sdio align packets

Pierre Ossman drzeus at drzeus.cx
Mon Oct 22 12:08:16 EDT 2007


Incoming packets have to be aligned or the IP stack becomes upset.
Make sure to shift them two bytes to achieve this.

Signed-off-by: Pierre Ossman <drzeus at drzeus.cx>
---

diff --git a/drivers/net/wireless/libertas/if_sdio.c b/drivers/net/wireless/libertas/if_sdio.c
index 5b13705..56dd568 100644
--- a/drivers/net/wireless/libertas/if_sdio.c
+++ b/drivers/net/wireless/libertas/if_sdio.c
@@ -175,12 +175,20 @@ static int if_sdio_handle_data(struct if_sdio_card *card,
 		goto out;
 	}
 
-	skb = dev_alloc_skb(MRVDRV_ETH_RX_PACKET_BUFFER_SIZE);
+	skb = dev_alloc_skb(MRVDRV_ETH_RX_PACKET_BUFFER_SIZE + NET_IP_ALIGN);
 	if (!skb) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
+	/*
+	 * The IP stack is littered with silly assumptions on alignment,
+	 * so we need to do a bit of layering violation here and make
+	 * assumptions about the size of the headers between us and the
+	 * IP stack.
+	 */
+	skb_reserve(skb, NET_IP_ALIGN);
+
 	data = skb_put(skb, size);
 
 	memcpy(data, buffer, size);
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