[IrDA]: irda-usb TX path optimization (was Re: IrDA spams logfiles - since 2.6.19)

Since we stop using dev_alloc_skb on the IrDA TX frame, we constantly run
into the case of the skb headroom being 0, and thus we call skb_cow for
every IrDA TX frame.
This patch uses a local buffer and memcpy the skb to it, saving us a
kmalloc for each of those IrDA TX frames.

Signed-off-by: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/net/irda/irda-usb.h b/drivers/net/irda/irda-usb.h
index 6b2271f18e77..e846c38224a3 100644
--- a/drivers/net/irda/irda-usb.h
+++ b/drivers/net/irda/irda-usb.h
@@ -156,6 +156,7 @@ struct irda_usb_cb {
         struct irlap_cb   *irlap;       /* The link layer we are binded to */
         struct qos_info qos;
         char *speed_buff;               /* Buffer for speed changes */
+        char *tx_buff;
 
         struct timeval stamp;
         struct timeval now;