diff --git a/shared-core/i915_mem.c b/shared-core/i915_mem.c
index 58f7b888..0e413d47 100644
--- a/shared-core/i915_mem.c
+++ b/shared-core/i915_mem.c
@@ -82,7 +82,7 @@ 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;
@@ -98,7 +98,7 @@ 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;
@@ -120,7 +120,7 @@ static struct mem_block *alloc_block( struct mem_block *heap, int size,
 
 	for (p = heap->next ; p != heap ; p = p->next) {
 		int start = (p->start + mask) & ~mask;
-		if (p->filp == 0 && start + size <= p->start + p->size)
+		if (p->filp == NULL && start + size <= p->start + p->size)
 			return split_block( p, start, size, filp );
 	}
 
@@ -141,12 +141,12 @@ 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.
 	 */
-	if (p->next->filp == 0) {
+	if (p->next->filp == NULL) {
 		struct mem_block *q = p->next;
 		p->size += q->size;
 		p->next = q->next;
@@ -154,7 +154,7 @@ static void free_block( struct mem_block *p )
 		DRM_FREE(q, sizeof(*q));
 	}
 
-	if (p->prev->filp == 0) {
+	if (p->prev->filp == NULL) {
 		struct mem_block *q = p->prev;
 		q->size += p->size;
 		q->next = p->next;
@@ -180,7 +180,7 @@ 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) );
@@ -202,7 +202,7 @@ void i915_mem_release( drm_device_t *dev,
 
 	for (p = heap->next ; p != heap ; p = p->next) {
 		if (p->filp == filp) {
-			p->filp = 0;
+			p->filp = NULL;
 			mark_block( dev, p, 0 );
 		}
 	}
@@ -211,7 +211,7 @@ void i915_mem_release( drm_device_t *dev,
 	 * 'heap' to stop it being subsumed.
 	 */
 	for (p = heap->next ; p != heap ; p = p->next) {
-		while (p->filp == 0 && p->next->filp == 0) {
+		while (p->filp == NULL && p->next->filp == NULL) {
 			struct mem_block *q = p->next;
 			p->size += q->size;
 			p->next = q->next;
diff --git a/shared/i915_mem.c b/shared/i915_mem.c
index 58f7b888..0e413d47 100644
--- a/shared/i915_mem.c
+++ b/shared/i915_mem.c
@@ -82,7 +82,7 @@ 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;
@@ -98,7 +98,7 @@ 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;
@@ -120,7 +120,7 @@ static struct mem_block *alloc_block( struct mem_block *heap, int size,
 
 	for (p = heap->next ; p != heap ; p = p->next) {
 		int start = (p->start + mask) & ~mask;
-		if (p->filp == 0 && start + size <= p->start + p->size)
+		if (p->filp == NULL && start + size <= p->start + p->size)
 			return split_block( p, start, size, filp );
 	}
 
@@ -141,12 +141,12 @@ 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.
 	 */
-	if (p->next->filp == 0) {
+	if (p->next->filp == NULL) {
 		struct mem_block *q = p->next;
 		p->size += q->size;
 		p->next = q->next;
@@ -154,7 +154,7 @@ static void free_block( struct mem_block *p )
 		DRM_FREE(q, sizeof(*q));
 	}
 
-	if (p->prev->filp == 0) {
+	if (p->prev->filp == NULL) {
 		struct mem_block *q = p->prev;
 		q->size += p->size;
 		q->next = p->next;
@@ -180,7 +180,7 @@ 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) );
@@ -202,7 +202,7 @@ void i915_mem_release( drm_device_t *dev,
 
 	for (p = heap->next ; p != heap ; p = p->next) {
 		if (p->filp == filp) {
-			p->filp = 0;
+			p->filp = NULL;
 			mark_block( dev, p, 0 );
 		}
 	}
@@ -211,7 +211,7 @@ void i915_mem_release( drm_device_t *dev,
 	 * 'heap' to stop it being subsumed.
 	 */
 	for (p = heap->next ; p != heap ; p = p->next) {
-		while (p->filp == 0 && p->next->filp == 0) {
+		while (p->filp == NULL && p->next->filp == NULL) {
 			struct mem_block *q = p->next;
 			p->size += q->size;
 			p->next = q->next;