rt2x00: Introduce extra queue entry sanity flag

Add a queue entry flag ENTRY_DATA_STATUS_PENDING,
which can be used to indicate a queue entry has
returned from the hardware and is waiting for
status processing. Using this flag we can add
some extra sanity checks to prevent queue corruption.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00usb.c b/drivers/net/wireless/rt2x00/rt2x00usb.c
index cd29ebc8a37b..8a16b5106a33 100644
--- a/drivers/net/wireless/rt2x00/rt2x00usb.c
+++ b/drivers/net/wireless/rt2x00/rt2x00usb.c
@@ -195,7 +195,8 @@ static void rt2x00usb_work_txdone(struct work_struct *work)
                 while (!rt2x00queue_empty(queue)) {
                         entry = rt2x00queue_get_entry(queue, Q_INDEX_DONE);
 
-                        if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
+                        if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) ||
+                            !test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
                                 break;
 
                         rt2x00usb_work_txdone_entry(entry);
@@ -237,7 +238,8 @@ static void rt2x00usb_kick_tx_entry(struct queue_entry *entry)
         u32 length;
         int status;
 
-        if (!test_and_clear_bit(ENTRY_DATA_PENDING, &entry->flags))
+        if (!test_and_clear_bit(ENTRY_DATA_PENDING, &entry->flags) ||
+            test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
                 return;
 
         /*
@@ -275,7 +277,8 @@ static void rt2x00usb_work_rxdone(struct work_struct *work)
         while (!rt2x00queue_empty(rt2x00dev->rx)) {
                 entry = rt2x00queue_get_entry(rt2x00dev->rx, Q_INDEX_DONE);
 
-                if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
+                if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) ||
+                    !test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
                         break;
 
                 /*
@@ -327,7 +330,8 @@ static void rt2x00usb_kick_rx_entry(struct queue_entry *entry)
         struct queue_entry_priv_usb *entry_priv = entry->priv_data;
         int status;
 
-        if (test_and_set_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
+        if (test_and_set_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) ||
+            test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags))
                 return;
 
         rt2x00lib_dmastart(entry);