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Subject[PATCH] : ir256_usb_cow_urballoc.diff
From
ir256_usb_cow_urballoc.diff :
---------------------------
o [FEATURE] Don't use skb_cow() unless we really need to
o [CORRECT] Reorder URB init to avoid races
o [CORRECT] USB dealy adds processing time, not removes it
<Following patch from Greg KH <greg@kroah.com> himself !!!>
o [CRITICA] Use dynamically allocated URBs (instead of statically)


diff -u -p linux/include/net/irda/irda-usb.d4.h linux/include/net/irda/irda-usb.h
--- linux/include/net/irda/irda-usb.d4.h Tue Mar 5 11:07:13 2002
+++ linux/include/net/irda/irda-usb.h Tue Mar 5 11:08:25 2002
@@ -139,10 +139,10 @@ struct irda_usb_cb {

wait_queue_head_t wait_q; /* for timeouts */

- struct urb rx_urb[IU_MAX_RX_URBS]; /* URBs used to receive data frames */
+ struct urb *rx_urb[IU_MAX_RX_URBS]; /* URBs used to receive data frames */
struct urb *idle_rx_urb; /* Pointer to idle URB in Rx path */
- struct urb tx_urb; /* URB used to send data frames */
- struct urb speed_urb; /* URB used to send speed commands */
+ struct urb *tx_urb; /* URB used to send data frames */
+ struct urb *speed_urb; /* URB used to send speed commands */

struct net_device *netdev; /* Yes! we are some kind of netdev. */
struct net_device_stats stats;
diff -u -p linux/drivers/net/irda/irda-usb.d4.c linux/drivers/net/irda/irda-usb.c
--- linux/drivers/net/irda/irda-usb.d4.c Tue Feb 26 09:48:41 2002
+++ linux/drivers/net/irda/irda-usb.c Tue Mar 5 12:13:10 2002
@@ -255,7 +255,7 @@ static void irda_usb_change_speed_xbofs(
self->new_speed, self->new_xbofs);

/* Grab the speed URB */
- urb = &self->speed_urb;
+ urb = self->speed_urb;
if (urb->status != 0) {
WARNING(__FUNCTION__ "(), URB still in use!\n");
return;
@@ -317,7 +317,7 @@ static void speed_bulk_callback(struct u
urb->status = 0;

/* If it was the speed URB, allow the stack to send more packets */
- if(urb == &self->speed_urb) {
+ if(urb == self->speed_urb) {
netif_wake_queue(self->netdev);
}
}
@@ -329,7 +329,7 @@ static void speed_bulk_callback(struct u
static int irda_usb_hard_xmit(struct sk_buff *skb, struct net_device *netdev)
{
struct irda_usb_cb *self = netdev->priv;
- struct urb *urb = &self->tx_urb;
+ struct urb *urb = self->tx_urb;
unsigned long flags;
s32 speed;
s16 xbofs;
@@ -378,10 +378,17 @@ static int irda_usb_hard_xmit(struct sk_
return 0;
}

- /* Make room for IrDA-USB header (note skb->len += USB_IRDA_HEADER) */
- if (skb_cow(skb, USB_IRDA_HEADER)) {
- dev_kfree_skb(skb);
- return 0;
+ /* 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) < USB_IRDA_HEADER) {
+ IRDA_DEBUG(0, __FUNCTION__ "(), Insuficient skb headroom.\n");
+ if (skb_cow(skb, USB_IRDA_HEADER)) {
+ WARNING(__FUNCTION__ "(), failed skb_cow() !!!\n");
+ dev_kfree_skb(skb);
+ return 0;
+ }
}

spin_lock_irqsave(&self->lock, flags);
@@ -432,7 +439,7 @@ static int irda_usb_hard_xmit(struct sk_
#ifdef IU_USB_MIN_RTT
/* Factor in USB delays -> Get rid of udelay() that
* would be lost in the noise - Jean II */
- diff -= IU_USB_MIN_RTT;
+ diff += IU_USB_MIN_RTT;
#endif /* IU_USB_MIN_RTT */
if (diff < 0)
diff += 1000000;
@@ -546,7 +553,7 @@ static void irda_usb_net_timeout(struct
}

/* Check speed URB */
- urb = &(self->speed_urb);
+ urb = self->speed_urb;
if (urb->status != 0) {
IRDA_DEBUG(0, "%s: Speed change timed out, urb->status=%d, urb->transfer_flags=0x%04X\n", netdev->name, urb->status, urb->transfer_flags);

@@ -571,7 +578,7 @@ static void irda_usb_net_timeout(struct
}

/* Check Tx URB */
- urb = &(self->tx_urb);
+ urb = self->tx_urb;
if (urb->status != 0) {
struct sk_buff *skb = urb->context;

@@ -848,8 +855,8 @@ done:
/* Submit the idle URB to replace the URB we've just received */
irda_usb_submit(self, skb, self->idle_rx_urb);
/* Recycle Rx URB : Now, the idle URB is the present one */
- self->idle_rx_urb = urb;
urb->context = NULL;
+ self->idle_rx_urb = urb;
}

/*------------------------------------------------------------------*/
@@ -952,13 +959,17 @@ static int irda_usb_net_open(struct net_
/* Allow IrLAP to send data to us */
netif_start_queue(netdev);

+ /* We submit all the Rx URB except for one that we keep idle.
+ * Need to be initialised before submitting other USBs, because
+ * in some cases as soon as we submit the URBs the USB layer
+ * will trigger a dummy receive - Jean II */
+ self->idle_rx_urb = self->rx_urb[IU_MAX_ACTIVE_RX_URBS];
+ self->idle_rx_urb->context = NULL;
+
/* Now that we can pass data to IrLAP, allow the USB layer
* to send us some data... */
for (i = 0; i < IU_MAX_ACTIVE_RX_URBS; i++)
- irda_usb_submit(self, NULL, &(self->rx_urb[i]));
- /* Note : we submit all the Rx URB except for one - Jean II */
- self->idle_rx_urb = &(self->rx_urb[IU_MAX_ACTIVE_RX_URBS]);
- self->idle_rx_urb->context = NULL;
+ irda_usb_submit(self, NULL, self->rx_urb[i]);

/* Ready to play !!! */
MOD_INC_USE_COUNT;
@@ -992,7 +1003,7 @@ static int irda_usb_net_close(struct net

/* Deallocate all the Rx path buffers (URBs and skb) */
for (i = 0; i < IU_MAX_RX_URBS; i++) {
- struct urb *urb = &(self->rx_urb[i]);
+ struct urb *urb = self->rx_urb[i];
struct sk_buff *skb = (struct sk_buff *) urb->context;
/* Cancel the receive command */
usb_unlink_urb(urb);
@@ -1003,8 +1014,8 @@ static int irda_usb_net_close(struct net
}
}
/* Cancel Tx and speed URB */
- usb_unlink_urb(&(self->tx_urb));
- usb_unlink_urb(&(self->speed_urb));
+ usb_unlink_urb(self->tx_urb);
+ usb_unlink_urb(self->speed_urb);

/* Stop and remove instance of IrLAP */
if (self->irlap)
@@ -1429,7 +1440,31 @@ static void *irda_usb_probe(struct usb_d
self->present = 0;
self->netopen = 0;

- /* Is this really necessary? */
+ /* Create all of the needed urbs */
+ for (i = 0; i < IU_MAX_RX_URBS; i++) {
+ self->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
+ if (!self->rx_urb[i]) {
+ int j;
+ for (j = 0; j < i; j++)
+ usb_free_urb(self->rx_urb[j]);
+ return NULL;
+ }
+ }
+ self->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!self->tx_urb) {
+ for (i = 0; i < IU_MAX_RX_URBS; i++)
+ usb_free_urb(self->rx_urb[i]);
+ return NULL;
+ }
+ self->speed_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!self->speed_urb) {
+ for (i = 0; i < IU_MAX_RX_URBS; i++)
+ usb_free_urb(self->rx_urb[i]);
+ usb_free_urb(self->tx_urb);
+ return NULL;
+ }
+
+ /* Is this really necessary? */
if (usb_set_configuration (dev, dev->config[0].bConfigurationValue) < 0) {
err("set_configuration failed");
return NULL;
@@ -1501,10 +1536,10 @@ static void irda_usb_disconnect(struct u
netif_stop_queue(self->netdev);
/* Stop all the receive URBs */
for (i = 0; i < IU_MAX_RX_URBS; i++)
- usb_unlink_urb(&(self->rx_urb[i]));
+ usb_unlink_urb(self->rx_urb[i]);
/* Cancel Tx and speed URB */
- usb_unlink_urb(&(self->tx_urb));
- usb_unlink_urb(&(self->speed_urb));
+ usb_unlink_urb(self->tx_urb);
+ usb_unlink_urb(self->speed_urb);

IRDA_DEBUG(0, __FUNCTION__ "(), postponing disconnect, network is still active...\n");
/* better not do anything just yet, usb_irda_cleanup()
@@ -1516,6 +1551,14 @@ static void irda_usb_disconnect(struct u
irda_usb_close(self);
/* No longer attached to USB bus */
self->usbdev = NULL;
+
+ /* Clean up our urbs */
+ for (i = 0; i < IU_MAX_RX_URBS; i++)
+ usb_free_urb(self->rx_urb[i]);
+ /* Cancel Tx and speed URB */
+ usb_free_urb(self->tx_urb);
+ usb_free_urb(self->speed_urb);
+
IRDA_DEBUG(0, __FUNCTION__ "(), USB IrDA Disconnected\n");
}

-
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