[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>
diff --git a/drivers/net/irda/irda-usb.c b/drivers/net/irda/irda-usb.c
index 3ca1082..80cbf3f 100644
--- a/drivers/net/irda/irda-usb.c
+++ b/drivers/net/irda/irda-usb.c
@@ -441,25 +441,13 @@
goto drop;
}
- /* Make sure there is room for IrDA-USB header. The actual
- * allocation will be done lower in skb_push().
- * Also, we don't use directly skb_cow(), because it require
- * headroom >= 16, which force unnecessary copies - Jean II */
- if (skb_headroom(skb) < self->header_length) {
- IRDA_DEBUG(0, "%s(), Insuficient skb headroom.\n", __FUNCTION__);
- if (skb_cow(skb, self->header_length)) {
- IRDA_WARNING("%s(), failed skb_cow() !!!\n", __FUNCTION__);
- goto drop;
- }
- }
+ memcpy(self->tx_buff + self->header_length, skb->data, skb->len);
/* Change setting for next frame */
-
if (self->capability & IUC_STIR421X) {
__u8 turnaround_time;
- __u8* frame;
+ __u8* frame = self->tx_buff;
turnaround_time = get_turnaround_time( skb );
- frame= skb_push(skb, self->header_length);
irda_usb_build_header(self, frame, 0);
frame[2] = turnaround_time;
if ((skb->len != 0) &&
@@ -472,17 +460,17 @@
frame[1] = 0;
}
} else {
- irda_usb_build_header(self, skb_push(skb, self->header_length), 0);
+ irda_usb_build_header(self, self->tx_buff, 0);
}
/* FIXME: Make macro out of this one */
((struct irda_skb_cb *)skb->cb)->context = self;
- usb_fill_bulk_urb(urb, self->usbdev,
+ usb_fill_bulk_urb(urb, self->usbdev,
usb_sndbulkpipe(self->usbdev, self->bulk_out_ep),
- skb->data, IRDA_SKB_MAX_MTU,
+ self->tx_buff, skb->len + self->header_length,
write_bulk_callback, skb);
- urb->transfer_buffer_length = skb->len;
+
/* This flag (URB_ZERO_PACKET) indicates that what we send is not
* a continuous stream of data but separate packets.
* In this case, the USB layer will insert an empty USB frame (TD)
@@ -1455,6 +1443,9 @@
/* Remove the speed buffer */
kfree(self->speed_buff);
self->speed_buff = NULL;
+
+ kfree(self->tx_buff);
+ self->tx_buff = NULL;
}
/********************** USB CONFIG SUBROUTINES **********************/
@@ -1753,9 +1744,14 @@
memset(self->speed_buff, 0, IRDA_USB_SPEED_MTU);
+ self->tx_buff = kzalloc(IRDA_SKB_MAX_MTU + self->header_length,
+ GFP_KERNEL);
+ if (self->tx_buff == NULL)
+ goto err_out_4;
+
ret = irda_usb_open(self);
if (ret)
- goto err_out_4;
+ goto err_out_5;
IRDA_MESSAGE("IrDA: Registered device %s\n", net->name);
usb_set_intfdata(intf, self);
@@ -1766,14 +1762,14 @@
self->needspatch = (ret < 0);
if (self->needspatch) {
IRDA_ERROR("STIR421X: Couldn't upload patch\n");
- goto err_out_5;
+ goto err_out_6;
}
/* replace IrDA class descriptor with what patched device is now reporting */
irda_desc = irda_usb_find_class_desc (self->usbintf);
if (irda_desc == NULL) {
ret = -ENODEV;
- goto err_out_5;
+ goto err_out_6;
}
if (self->irda_desc)
kfree (self->irda_desc);
@@ -1782,9 +1778,10 @@
}
return 0;
-
-err_out_5:
+err_out_6:
unregister_netdev(self->netdev);
+err_out_5:
+ kfree(self->tx_buff);
err_out_4:
kfree(self->speed_buff);
err_out_3: