firewire: net: fix memory leaks

a) fwnet_transmit_packet_done used to poison ptask->pt_link by list_del.
If fwnet_send_packet checked later whether it was responsible to clean
up (in the border case that the TX soft IRQ was outpaced by the AT-req
tasklet on another CPU), it missed this because ptask->pt_link was no
longer shown as empty.

b) If fwnet_write_complete got an rcode other than RCODE_COMPLETE, we
missed to free the skb and ptask entirely.

Also, count stats.tx_dropped and stats.tx_errors when rcode != 0.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 31 insertions, 4 deletions

diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c
index e2e968e732bc..3a27cee5bf26 100644
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -916,9 +916,10 @@ static void fwnet_transmit_packet_done(struct fwnet_packet_task *ptask)
 
         /* Check whether we or the networking TX soft-IRQ is last user. */
         free = (ptask->outstanding_pkts == 0 && !list_empty(&ptask->pt_link));
+        if (free)
+                list_del(&ptask->pt_link);
 
         if (ptask->outstanding_pkts == 0) {
-                list_del(&ptask->pt_link);
                 dev->netdev->stats.tx_packets++;
                 dev->netdev->stats.tx_bytes += skb->len;
         }
@@ -973,6 +974,31 @@ static void fwnet_transmit_packet_done(struct fwnet_packet_task *ptask)
                 fwnet_free_ptask(ptask);
 }
 
+static void fwnet_transmit_packet_failed(struct fwnet_packet_task *ptask)
+{
+        struct fwnet_device *dev = ptask->dev;
+        unsigned long flags;
+        bool free;
+
+        spin_lock_irqsave(&dev->lock, flags);
+
+        /* One fragment failed; don't try to send remaining fragments. */
+        ptask->outstanding_pkts = 0;
+
+        /* Check whether we or the networking TX soft-IRQ is last user. */
+        free = !list_empty(&ptask->pt_link);
+        if (free)
+                list_del(&ptask->pt_link);
+
+        dev->netdev->stats.tx_dropped++;
+        dev->netdev->stats.tx_errors++;
+
+        spin_unlock_irqrestore(&dev->lock, flags);
+
+        if (free)
+                fwnet_free_ptask(ptask);
+}
+
 static void fwnet_write_complete(struct fw_card *card, int rcode,
                                  void *payload, size_t length, void *data)
 {
@@ -980,11 +1006,12 @@ static void fwnet_write_complete(struct fw_card *card, int rcode,
 
         ptask = data;
 
-        if (rcode == RCODE_COMPLETE)
+        if (rcode == RCODE_COMPLETE) {
                 fwnet_transmit_packet_done(ptask);
-        else
+        } else {
                 fw_error("fwnet_write_complete: failed: %x\n", rcode);
-                /* ??? error recovery */
+                fwnet_transmit_packet_failed(ptask);
+        }
 }
 
 static int fwnet_send_packet(struct fwnet_packet_task *ptask)