On Sat, 2013-12-28 at 23:18 +0800, Ding Tianhong wrote:

于 2013/12/28 21:58, Sergei Shtylyov 写道:

quoted

Hello.

On 28-12-2013 10:17, Ding Tianhong wrote:

quoted

Use possibly more efficient ether_addr_equal
to instead of memcmp.

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Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Ding Tianhong <redacted>
---
  drivers/net/ethernet/packetengines/yellowfin.c |   12 ++++++------
  1 files changed, 6 insertions(+), 6 deletions(-)

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diff --git a/drivers/net/ethernet/packetengines/yellowfin.c b/drivers/net/ethernet/packetengines/yellowfin.c
index d28593b..b83ac0e 100644
--- a/drivers/net/ethernet/packetengines/yellowfin.c
+++ b/drivers/net/ethernet/packetengines/yellowfin.c

@@ -1097,12 +1097,12 @@ static int yellowfin_rx(struct net_device *dev)
              if (status2 & 0x80) dev->stats.rx_dropped++;
  #ifdef YF_PROTOTYPE        /* Support for prototype hardware errata. */
          } else if ((yp->flags & HasMACAddrBug)  &&
-            memcmp(le32_to_cpu(yp->rx_ring_dma +
-                entry*sizeof(struct yellowfin_desc)),
-                dev->dev_addr, 6) != 0 &&
-            memcmp(le32_to_cpu(yp->rx_ring_dma +
-                entry*sizeof(struct yellowfin_desc)),
-                "\377\377\377\377\377\377", 6) != 0) {
+            !ether_addr_equal(le32_to_cpu(yp->rx_ring_dma +
+                              entry * sizeof(struct yellowfin_desc)),
+                              dev->dev_addr) &&

   Previous line was aligned correctly, the above line should start under le32_to_cpu.

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+            !ether_addr_equal(le32_to_cpu(yp->rx_ring_dma +
+                              entry * sizeof(struct yellowfin_desc)),

   Start the continuation lines under 'yp', please.

quoted

+                              "\377\377\377\377\377\377")) {

   This line should start under le32_to_cpu.

WBR, Sergei

Hi sergei:
you mean this way?
	!ether_addr_equal(le32_to_cpu(yp->rx_ring_dma +
				      entry * sizeof(struct yellowfin_desc)),
			  dev->dev_addr) &&

	!ether_addr_equal(le32_to_cpu(yp->rx_ring_dma +
				      entry * sizeof(struct yellowfin_desc)),
			  "\377\377\377\377\377\377")) {

Does this really matter?
Does anyone have a packetengine NIC anymore?

\377 octal is 0xff, so this is matching a broadcast address.
is_broadcast_ether_addr(addr) would be appropriate.

So would using a temporary address.

u8 *addr = (u8 *)(unsigned long)le32_to_cpu(etc)

but the whole thing looks very suspect as an le32
value could not be added to correctly on a
big-endian arch anyway.

My guess is this was tested only on an x86 and
it should be:

	u8 *addr = (u8 *)(unsigned long)(le32_to_cpu(yp->rx_ring_dma) +
					 entry * sizeof(struct yellowfin_desc));

It maybe better just to leave these two alone.