p54usb: fix stalls caused by urb allocation failures

This patch squashes a few old bugs, which have been around since
the initial version of p54usb in one form or another.

we never freed a orphaned frame, when were denied the resources,
which are necessary to pass the data into the usb subsystem.
As a result we could end up with a full queue that wasn't emptied,
until the device was brought down.

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/p54/p54usb.c b/drivers/net/wireless/p54/p54usb.c
index 461d88f5ceb74fcf708f5ef549bf0be4d86d0cf5..e44460ff149cb4a4eddd82fc600af71fc63c3e90 100644 (file)
--- a/drivers/net/wireless/p54/p54usb.c
+++ b/drivers/net/wireless/p54/p54usb.c
@@ -246,8 +246,10 @@ static void p54u_tx_lm87(struct ieee80211_hw *dev, struct sk_buff *skb)
        struct lm87_tx_hdr *hdr = (void *)skb->data - sizeof(*hdr);
 
        data_urb = usb_alloc_urb(0, GFP_ATOMIC);
-       if (!data_urb)
+       if (!data_urb) {
+               p54_free_skb(dev, skb);
                return;
+       }
 
        hdr->chksum = p54u_lm87_chksum((__le32 *)skb->data, skb->len);
        hdr->device_addr = ((struct p54_hdr *)skb->data)->req_id;
@@ -269,27 +271,22 @@ static void p54u_tx_lm87(struct ieee80211_hw *dev, struct sk_buff *skb)
 static void p54u_tx_net2280(struct ieee80211_hw *dev, struct sk_buff *skb)
 {
        struct p54u_priv *priv = dev->priv;
-       struct urb *int_urb, *data_urb;
+       struct urb *int_urb = NULL, *data_urb = NULL;
        struct net2280_tx_hdr *hdr = (void *)skb->data - sizeof(*hdr);
-       struct net2280_reg_write *reg;
-       int err = 0;
+       struct net2280_reg_write *reg = NULL;
+       int err = -ENOMEM;
 
        reg = kmalloc(sizeof(*reg), GFP_ATOMIC);
        if (!reg)
-               return;
+               goto out;
 
        int_urb = usb_alloc_urb(0, GFP_ATOMIC);
-       if (!int_urb) {
-               kfree(reg);
-               return;
-       }
+       if (!int_urb)
+               goto out;
 
        data_urb = usb_alloc_urb(0, GFP_ATOMIC);
-       if (!data_urb) {
-               kfree(reg);
-               usb_free_urb(int_urb);
-               return;
-       }
+       if (!data_urb)
+               goto out;
 
        reg->port = cpu_to_le16(NET2280_DEV_U32);
        reg->addr = cpu_to_le32(P54U_DEV_BASE);
@@ -304,11 +301,12 @@ static void p54u_tx_net2280(struct ieee80211_hw *dev, struct sk_buff *skb)
                p54u_tx_dummy_cb, dev);
 
        /*
-        * This flag triggers a code path in the USB subsystem that will
-        * free what's inside the transfer_buffer after the callback routine
-        * has completed.
+        * URB_FREE_BUFFER triggers a code path in the USB subsystem that will
+        * free what is inside the transfer_buffer after the last reference to
+        * the int_urb is dropped.
         */
        int_urb->transfer_flags |= URB_FREE_BUFFER | URB_ZERO_PACKET;
+       reg = NULL;
 
        usb_fill_bulk_urb(data_urb, priv->udev,
                          usb_sndbulkpipe(priv->udev, P54U_PIPE_DATA),
@@ -329,12 +327,12 @@ static void p54u_tx_net2280(struct ieee80211_hw *dev, struct sk_buff *skb)
                usb_unanchor_urb(data_urb);
                goto out;
        }
- out:
+out:
        usb_free_urb(int_urb);
        usb_free_urb(data_urb);
 
        if (err) {
-               skb_pull(skb, sizeof(*hdr));
+               kfree(reg);
                p54_free_skb(dev, skb);
        }
 }