diff --git a/linux-core/drm_bufs.c b/linux-core/drm_bufs.c
index d50090bb..69511f91 100644
--- a/linux-core/drm_bufs.c
+++ b/linux-core/drm_bufs.c
@@ -126,7 +126,7 @@ int DRM(addmap)( struct inode *inode, struct file *filp,
 		return -EINVAL;
 	}
 	map->mtrr   = -1;
-	map->handle = 0;
+	map->handle = NULL;
 
 	switch ( map->type ) {
 	case _DRM_REGISTERS:
@@ -469,7 +469,7 @@ int DRM(addbufs_agp)( struct inode *inode, struct file *filp,
 		buf->waiting = 0;
 		buf->pending = 0;
 		init_waitqueue_head( &buf->dma_wait );
-		buf->filp    = 0;
+		buf->filp    = NULL;
 
 		buf->dev_priv_size = sizeof(DRIVER_BUF_PRIV_T);
 		buf->dev_private = DRM(alloc)( sizeof(DRIVER_BUF_PRIV_T),
@@ -693,7 +693,7 @@ int DRM(addbufs_pci)( struct inode *inode, struct file *filp,
 			buf->waiting = 0;
 			buf->pending = 0;
 			init_waitqueue_head( &buf->dma_wait );
-			buf->filp    = 0;
+			buf->filp    = NULL;
 
 			buf->dev_priv_size = sizeof(DRIVER_BUF_PRIV_T);
 			buf->dev_private = DRM(alloc)( sizeof(DRIVER_BUF_PRIV_T),
diff --git a/linux-core/drm_drv.c b/linux-core/drm_drv.c
index c4d4391d..42831be0 100644
--- a/linux-core/drm_drv.c
+++ b/linux-core/drm_drv.c
@@ -545,7 +545,7 @@ static int DRM(takedown)( drm_device_t *dev )
 #endif
 	if ( dev->lock.hw_lock ) {
 		dev->sigdata.lock = dev->lock.hw_lock = NULL; /* SHM removed */
-		dev->lock.filp = 0;
+		dev->lock.filp = NULL;
 		wake_up_interruptible( &dev->lock.lock_queue );
 	}
 	
diff --git a/linux/drm_bufs.h b/linux/drm_bufs.h
index d50090bb..69511f91 100644
--- a/linux/drm_bufs.h
+++ b/linux/drm_bufs.h
@@ -126,7 +126,7 @@ int DRM(addmap)( struct inode *inode, struct file *filp,
 		return -EINVAL;
 	}
 	map->mtrr   = -1;
-	map->handle = 0;
+	map->handle = NULL;
 
 	switch ( map->type ) {
 	case _DRM_REGISTERS:
@@ -469,7 +469,7 @@ int DRM(addbufs_agp)( struct inode *inode, struct file *filp,
 		buf->waiting = 0;
 		buf->pending = 0;
 		init_waitqueue_head( &buf->dma_wait );
-		buf->filp    = 0;
+		buf->filp    = NULL;
 
 		buf->dev_priv_size = sizeof(DRIVER_BUF_PRIV_T);
 		buf->dev_private = DRM(alloc)( sizeof(DRIVER_BUF_PRIV_T),
@@ -693,7 +693,7 @@ int DRM(addbufs_pci)( struct inode *inode, struct file *filp,
 			buf->waiting = 0;
 			buf->pending = 0;
 			init_waitqueue_head( &buf->dma_wait );
-			buf->filp    = 0;
+			buf->filp    = NULL;
 
 			buf->dev_priv_size = sizeof(DRIVER_BUF_PRIV_T);
 			buf->dev_private = DRM(alloc)( sizeof(DRIVER_BUF_PRIV_T),
diff --git a/linux/drm_drv.h b/linux/drm_drv.h
index c4d4391d..42831be0 100644
--- a/linux/drm_drv.h
+++ b/linux/drm_drv.h
@@ -545,7 +545,7 @@ static int DRM(takedown)( drm_device_t *dev )
 #endif
 	if ( dev->lock.hw_lock ) {
 		dev->sigdata.lock = dev->lock.hw_lock = NULL; /* SHM removed */
-		dev->lock.filp = 0;
+		dev->lock.filp = NULL;
 		wake_up_interruptible( &dev->lock.lock_queue );
 	}
 	
diff --git a/shared-core/radeon_mem.c b/shared-core/radeon_mem.c
index 83e2f6c0..96b76ae0 100644
--- a/shared-core/radeon_mem.c
+++ b/shared-core/radeon_mem.c
@@ -49,7 +49,7 @@ static struct mem_block *split_block(struct mem_block *p, int start, int size,
 			goto out;
 		newblock->start = start;
 		newblock->size = p->size - (start - p->start);
-		newblock->filp = 0;
+		newblock->filp = NULL;
 		newblock->next = p->next;
 		newblock->prev = p;
 		p->next->prev = newblock;
@@ -65,7 +65,7 @@ static struct mem_block *split_block(struct mem_block *p, int start, int size,
 			goto out;
 		newblock->start = start + size;
 		newblock->size = p->size - size;
-		newblock->filp = 0;
+		newblock->filp = NULL;
 		newblock->next = p->next;
 		newblock->prev = p;
 		p->next->prev = newblock;
@@ -108,7 +108,7 @@ static struct mem_block *find_block( struct mem_block *heap, int start )
 
 static void free_block( struct mem_block *p )
 {
-	p->filp = 0;
+	p->filp = NULL;
 
 	/* Assumes a single contiguous range.  Needs a special filp in
 	 * 'heap' to stop it being subsumed.
@@ -147,7 +147,7 @@ static int init_heap(struct mem_block **heap, int start, int size)
 
 	blocks->start = start;
 	blocks->size = size;
-	blocks->filp = 0;
+	blocks->filp = NULL;
 	blocks->next = blocks->prev = *heap;
 
 	memset( *heap, 0, sizeof(**heap) );
@@ -168,7 +168,7 @@ void radeon_mem_release( DRMFILE filp, struct mem_block *heap )
 
 	for (p = heap->next ; p != heap ; p = p->next) {
 		if (p->filp == filp) 
-			p->filp = 0;
+			p->filp = NULL;
 	}
 
 	/* Assumes a single contiguous range.  Needs a special filp in
@@ -201,7 +201,7 @@ void radeon_mem_takedown( struct mem_block **heap )
 	}
 
 	DRM_FREE( *heap, sizeof(**heap) );
-	*heap = 0;
+	*heap = NULL;
 }
 
 
@@ -217,7 +217,7 @@ static struct mem_block **get_heap( drm_radeon_private_t *dev_priv,
 	case RADEON_MEM_REGION_FB:
 		return &dev_priv->fb_heap;
 	default:
-		return 0;
+		return NULL;
 	}
 }
 
diff --git a/shared-core/radeon_state.c b/shared-core/radeon_state.c
index 05184162..4d760e92 100644
--- a/shared-core/radeon_state.c
+++ b/shared-core/radeon_state.c
@@ -2310,7 +2310,7 @@ int radeon_cp_cmdbuf( DRM_IOCTL_ARGS )
 	drm_radeon_private_t *dev_priv = dev->dev_private;
 	drm_file_t *filp_priv;
 	drm_device_dma_t *dma = dev->dma;
-	drm_buf_t *buf = 0;
+	drm_buf_t *buf = NULL;
 	int idx;
 	drm_radeon_cmd_buffer_t cmdbuf;
 	drm_radeon_cmd_header_t header;
diff --git a/shared-core/sis_ds.c b/shared-core/sis_ds.c
index 543ce71e..08391554 100644
--- a/shared-core/sis_ds.c
+++ b/shared-core/sis_ds.c
@@ -165,7 +165,7 @@ memHeap_t *mmInit(int ofs,
 	PMemBlock blocks;
 
 	if (size <= 0)
-		return 0;
+		return NULL;
 
 	blocks = (TMemBlock *)DRM(calloc)(1, sizeof(TMemBlock), DRM_MEM_DRIVER);
 	if (blocks != NULL) {
@@ -174,7 +174,7 @@ memHeap_t *mmInit(int ofs,
 		blocks->free = 1;
 		return (memHeap_t *)blocks;
 	} else
-		return 0;
+		return NULL;
 }
 
 /* Checks if a pointer 'b' is part of the heap 'heap' */
diff --git a/shared/radeon_mem.c b/shared/radeon_mem.c
index 83e2f6c0..96b76ae0 100644
--- a/shared/radeon_mem.c
+++ b/shared/radeon_mem.c
@@ -49,7 +49,7 @@ static struct mem_block *split_block(struct mem_block *p, int start, int size,
 			goto out;
 		newblock->start = start;
 		newblock->size = p->size - (start - p->start);
-		newblock->filp = 0;
+		newblock->filp = NULL;
 		newblock->next = p->next;
 		newblock->prev = p;
 		p->next->prev = newblock;
@@ -65,7 +65,7 @@ static struct mem_block *split_block(struct mem_block *p, int start, int size,
 			goto out;
 		newblock->start = start + size;
 		newblock->size = p->size - size;
-		newblock->filp = 0;
+		newblock->filp = NULL;
 		newblock->next = p->next;
 		newblock->prev = p;
 		p->next->prev = newblock;
@@ -108,7 +108,7 @@ static struct mem_block *find_block( struct mem_block *heap, int start )
 
 static void free_block( struct mem_block *p )
 {
-	p->filp = 0;
+	p->filp = NULL;
 
 	/* Assumes a single contiguous range.  Needs a special filp in
 	 * 'heap' to stop it being subsumed.
@@ -147,7 +147,7 @@ static int init_heap(struct mem_block **heap, int start, int size)
 
 	blocks->start = start;
 	blocks->size = size;
-	blocks->filp = 0;
+	blocks->filp = NULL;
 	blocks->next = blocks->prev = *heap;
 
 	memset( *heap, 0, sizeof(**heap) );
@@ -168,7 +168,7 @@ void radeon_mem_release( DRMFILE filp, struct mem_block *heap )
 
 	for (p = heap->next ; p != heap ; p = p->next) {
 		if (p->filp == filp) 
-			p->filp = 0;
+			p->filp = NULL;
 	}
 
 	/* Assumes a single contiguous range.  Needs a special filp in
@@ -201,7 +201,7 @@ void radeon_mem_takedown( struct mem_block **heap )
 	}
 
 	DRM_FREE( *heap, sizeof(**heap) );
-	*heap = 0;
+	*heap = NULL;
 }
 
 
@@ -217,7 +217,7 @@ static struct mem_block **get_heap( drm_radeon_private_t *dev_priv,
 	case RADEON_MEM_REGION_FB:
 		return &dev_priv->fb_heap;
 	default:
-		return 0;
+		return NULL;
 	}
 }
 
diff --git a/shared/radeon_state.c b/shared/radeon_state.c
index 05184162..4d760e92 100644
--- a/shared/radeon_state.c
+++ b/shared/radeon_state.c
@@ -2310,7 +2310,7 @@ int radeon_cp_cmdbuf( DRM_IOCTL_ARGS )
 	drm_radeon_private_t *dev_priv = dev->dev_private;
 	drm_file_t *filp_priv;
 	drm_device_dma_t *dma = dev->dma;
-	drm_buf_t *buf = 0;
+	drm_buf_t *buf = NULL;
 	int idx;
 	drm_radeon_cmd_buffer_t cmdbuf;
 	drm_radeon_cmd_header_t header;
diff --git a/shared/sis_ds.c b/shared/sis_ds.c
index 543ce71e..08391554 100644
--- a/shared/sis_ds.c
+++ b/shared/sis_ds.c
@@ -165,7 +165,7 @@ memHeap_t *mmInit(int ofs,
 	PMemBlock blocks;
 
 	if (size <= 0)
-		return 0;
+		return NULL;
 
 	blocks = (TMemBlock *)DRM(calloc)(1, sizeof(TMemBlock), DRM_MEM_DRIVER);
 	if (blocks != NULL) {
@@ -174,7 +174,7 @@ memHeap_t *mmInit(int ofs,
 		blocks->free = 1;
 		return (memHeap_t *)blocks;
 	} else
-		return 0;
+		return NULL;
 }
 
 /* Checks if a pointer 'b' is part of the heap 'heap' */