[PATCH] sky2: receive buffer alignment

Need to make sure that sky2 receive buffers are 64 bit
aligned. Also, don't need to start off with GFP_ATOMIC
on initial setup.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 23 insertions, 7 deletions

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index f5d697c0c031..996275245144 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -75,6 +75,7 @@
 #define RX_LE_BYTES             (RX_LE_SIZE*sizeof(struct sky2_rx_le))
 #define RX_MAX_PENDING          (RX_LE_SIZE/2 - 2)
 #define RX_DEF_PENDING          RX_MAX_PENDING
+#define RX_SKB_ALIGN            8
 
 #define TX_RING_SIZE            512
 #define TX_DEF_PENDING          (TX_RING_SIZE - 1)
@@ -905,15 +906,30 @@ static void sky2_vlan_rx_kill_vid(struct net_device *dev, unsigned short vid)
 #endif
 
 /*
+ * It appears the hardware has a bug in the FIFO logic that
+ * cause it to hang if the FIFO gets overrun and the receive buffer
+ * is not aligned. ALso alloc_skb() won't align properly if slab
+ * debugging is enabled.
+ */
+static inline struct sk_buff *sky2_alloc_skb(unsigned int size, gfp_t gfp_mask)
+{
+        struct sk_buff *skb;
+
+        skb = alloc_skb(size + RX_SKB_ALIGN, gfp_mask);
+        if (likely(skb)) {
+                unsigned long p = (unsigned long) skb->data;
+                skb_reserve(skb,
+                        ((p + RX_SKB_ALIGN - 1) & ~(RX_SKB_ALIGN - 1)) - p);
+        }
+
+        return skb;
+}
+
+/*
  * Allocate and setup receiver buffer pool.
  * In case of 64 bit dma, there are 2X as many list elements
  * available as ring entries
  * and need to reserve one list element so we don't wrap around.
- *
- * It appears the hardware has a bug in the FIFO logic that
- * cause it to hang if the FIFO gets overrun and the receive buffer
- * is not aligned.  This means we can't use skb_reserve to align
- * the IP header.
  */
 static int sky2_rx_start(struct sky2_port *sky2)
 {
@@ -929,7 +945,7 @@ static int sky2_rx_start(struct sky2_port *sky2)
         for (i = 0; i < sky2->rx_pending; i++) {
                 struct ring_info *re = sky2->rx_ring + i;
 
-                re->skb = dev_alloc_skb(sky2->rx_bufsize);
+                re->skb = sky2_alloc_skb(sky2->rx_bufsize, GFP_KERNEL);
                 if (!re->skb)
                         goto nomem;
 
@@ -1713,7 +1729,7 @@ static struct sk_buff *sky2_receive(struct sky2_port *sky2,
         } else {
                 struct sk_buff *nskb;
 
-                nskb = dev_alloc_skb(sky2->rx_bufsize);
+                nskb = sky2_alloc_skb(sky2->rx_bufsize, GFP_ATOMIC);
                 if (!nskb)
                         goto resubmit;