net: cadence_gem: Fix Tx descriptor update

The local variable "desc" was being used to read-modify-write the first descriptor (of a multi-desc packet) upon packet completion. desc however continues to be used by the code as the current descriptor. Give this first desc RMW it's own local variable to avoid trampling. Signed-off-by: Peter Crosthwaite <[email protected]> Signed-off-by: Michael Tokarev <[email protected]>
gic4107 · Jun 10, 2014 · 6ab57a6 · 6ab57a6
1 parent 3334e92
commit 6ab57a6
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
@@ -911,14 +911,16 @@ static void gem_transmit(GemState *s)
 
         /* Last descriptor for this packet; hand the whole thing off */
         if (tx_desc_get_last(desc)) {
+            unsigned    desc_first[2];
+
             /* Modify the 1st descriptor of this packet to be owned by
              * the processor.
              */
-            cpu_physical_memory_read(s->tx_desc_addr,
-                                     (uint8_t *)&desc[0], sizeof(desc));
-            tx_desc_set_used(desc);
-            cpu_physical_memory_write(s->tx_desc_addr,
-                                      (uint8_t *)&desc[0], sizeof(desc));
+            cpu_physical_memory_read(s->tx_desc_addr, (uint8_t *)desc_first,
+                                     sizeof(desc_first));
+            tx_desc_set_used(desc_first);
+            cpu_physical_memory_write(s->tx_desc_addr, (uint8_t *)desc_first,
+                                      sizeof(desc_first));
             /* Advance the hardare current descriptor past this packet */
             if (tx_desc_get_wrap(desc)) {
                 s->tx_desc_addr = s->regs[GEM_TXQBASE];