[PATCH 07/27] drm/radeon: add proper locking to the SA v3

[j.glisse at gmail.com]

From: Christian König <deathsimple at vodafone.de>

Make the suballocator self containing to locking.

v2: split the bugfix into a seperate patch.
v3: Jerome Glisse use mutex, no reason to use spinlock that
    are more heavyweight than mutex

Signed-off-by: Christian König <deathsimple at vodafone.de>
Signed-off-by: Jerome Glisse <jglisse at redhat.com>
---
 drivers/gpu/drm/radeon/radeon.h    |    1 +
 drivers/gpu/drm/radeon/radeon_sa.c |   15 +++++++++------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 85a3aa9..34c1041 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -381,6 +381,7 @@ struct radeon_bo_list {
  * alignment).
  */
 struct radeon_sa_manager {
+	struct mutex		mutex;
 	struct radeon_bo	*bo;
 	struct list_head	sa_bo;
 	unsigned		size;
diff --git a/drivers/gpu/drm/radeon/radeon_sa.c b/drivers/gpu/drm/radeon/radeon_sa.c
index 8fbfe69..8c76c2e 100644
--- a/drivers/gpu/drm/radeon/radeon_sa.c
+++ b/drivers/gpu/drm/radeon/radeon_sa.c
@@ -37,6 +37,7 @@ int radeon_sa_bo_manager_init(struct radeon_device *rdev,
 {
 	int r;
 
+	mutex_init(&sa_manager->mutex);
 	sa_manager->bo = NULL;
 	sa_manager->size = size;
 	sa_manager->domain = domain;
@@ -139,15 +140,15 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
 
 	BUG_ON(align > RADEON_GPU_PAGE_SIZE);
 	BUG_ON(size > sa_manager->size);
+	mutex_lock(&sa_manager->mutex);
 
 	/* no one ? */
-	head = sa_manager->sa_bo.prev;
 	if (list_empty(&sa_manager->sa_bo)) {
+		head = &sa_manager->sa_bo;
 		goto out;
 	}
 
 	/* look for a hole big enough */
-	offset = 0;
 	list_for_each_entry(tmp, &sa_manager->sa_bo, list) {
 		/* room before this object ? */
 		if (offset < tmp->offset && (tmp->offset - offset) >= size) {
@@ -157,9 +158,8 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
 		offset = tmp->offset + tmp->size;
 		wasted = offset % align;
 		if (wasted) {
-			wasted = align - wasted;
+			offset += align - wasted;
 		}
-		offset += wasted;
 	}
 	/* room at the end ? */
 	head = sa_manager->sa_bo.prev;
@@ -167,11 +167,11 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
 	offset = tmp->offset + tmp->size;
 	wasted = offset % align;
 	if (wasted) {
-		wasted = align - wasted;
+		offset += wasted = align - wasted;
 	}
-	offset += wasted;
 	if ((sa_manager->size - offset) < size) {
 		/* failed to find somethings big enough */
+		mutex_unlock(&sa_manager->mutex);
 		return -ENOMEM;
 	}
 
@@ -180,10 +180,13 @@ out:
 	sa_bo->offset = offset;
 	sa_bo->size = size;
 	list_add(&sa_bo->list, head);
+	mutex_unlock(&sa_manager->mutex);
 	return 0;
 }
 
 void radeon_sa_bo_free(struct radeon_device *rdev, struct radeon_sa_bo *sa_bo)
 {
+	mutex_lock(&sa_bo->manager->mutex);
 	list_del_init(&sa_bo->list);
+	mutex_unlock(&sa_bo->manager->mutex);
 }
-- 
1.7.7.6