ARM: 6024/1: bcmring: fix missing down on semaphore in dma.c

Added missing down on the memMap->lock semaphore. Also fixed a return
statement so that we always exit with an up (i.e. early exit via return
is not allowed)
Signed-off-by: Leo Hao Chen <leochen@broadcom.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-bcmring/dma.c

@@ -2221,11 +2221,15 @@ EXPORT_SYMBOL(dma_map_create_descriptor_ring);
 int dma_unmap(DMA_MemMap_t *memMap,	/* Stores state information about the map */
 	      int dirtied	/* non-zero if any of the pages were modified */
     ) {
+
+	int rc = 0;
 	int regionIdx;
 	int segmentIdx;
 	DMA_Region_t *region;
 	DMA_Segment_t *segment;
 
+	down(&memMap->lock);
+
 	for (regionIdx = 0; regionIdx < memMap->numRegionsUsed; regionIdx++) {
 		region = &memMap->region[regionIdx];
 
@@ -2239,7 +2243,8 @@ int dma_unmap(DMA_MemMap_t *memMap,	/* Stores state information about the map */
 					printk(KERN_ERR
 					       "%s: vmalloc'd pages are not yet supported\n",
 					       __func__);
-					return -EINVAL;
+					rc = -EINVAL;
+					goto out;
 				}
 
 			case DMA_MEM_TYPE_KMALLOC:
@@ -2276,7 +2281,8 @@ int dma_unmap(DMA_MemMap_t *memMap,	/* Stores state information about the map */
 					printk(KERN_ERR
 					       "%s: Unsupported memory type: %d\n",
 					       __func__, region->memType);
-					return -EINVAL;
+					rc = -EINVAL;
+					goto out;
 				}
 			}
 
@@ -2314,9 +2320,10 @@ int dma_unmap(DMA_MemMap_t *memMap,	/* Stores state information about the map */
 	memMap->numRegionsUsed = 0;
 	memMap->inUse = 0;
 
+out:
 	up(&memMap->lock);
 
-	return 0;
+	return rc;
 }
 
 EXPORT_SYMBOL(dma_unmap);