[RFC PATCH 11/24] vhost_iotlb: split out IOTLB initialization

[Jason Wang]

This patch split out IOTLB initialization logic into a new
helper. This allows vhost to implement device specific IOTLB
allocation logic.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
 drivers/vhost/iotlb.c       | 23 ++++++++++++++++++-----
 include/linux/vhost_iotlb.h |  2 ++
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/iotlb.c b/drivers/vhost/iotlb.c
index 1f0ca6e44410..36d785efd038 100644
--- a/drivers/vhost/iotlb.c
+++ b/drivers/vhost/iotlb.c
@@ -98,6 +98,23 @@ void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last)
 }
 EXPORT_SYMBOL_GPL(vhost_iotlb_del_range);
 
+/**
+ * vhost_iotlb_init - initialize a vhost IOTLB
+ * @iotlb: the IOTLB that needs to be initialized
+ * @limit: maximum number of IOTLB entries
+ * @flags: VHOST_IOTLB_FLAG_XXX
+ */
+void vhost_iotlb_init(struct vhost_iotlb *iotlb, unsigned int limit,
+		      unsigned int flags)
+{
+	iotlb->root = RB_ROOT_CACHED;
+	iotlb->limit = limit;
+	iotlb->nmaps = 0;
+	iotlb->flags = flags;
+	INIT_LIST_HEAD(&iotlb->list);
+}
+EXPORT_SYMBOL_GPL(vhost_iotlb_init);
+
 /**
  * vhost_iotlb_alloc - add a new vhost IOTLB
  * @limit: maximum number of IOTLB entries
@@ -112,11 +129,7 @@ struct vhost_iotlb *vhost_iotlb_alloc(unsigned int limit, unsigned int flags)
 	if (!iotlb)
 		return NULL;
 
-	iotlb->root = RB_ROOT_CACHED;
-	iotlb->limit = limit;
-	iotlb->nmaps = 0;
-	iotlb->flags = flags;
-	INIT_LIST_HEAD(&iotlb->list);
+	vhost_iotlb_init(iotlb, limit, flags);
 
 	return iotlb;
 }
diff --git a/include/linux/vhost_iotlb.h b/include/linux/vhost_iotlb.h
index 6b09b786a762..c0df193ec3e1 100644
--- a/include/linux/vhost_iotlb.h
+++ b/include/linux/vhost_iotlb.h
@@ -33,6 +33,8 @@ int vhost_iotlb_add_range(struct vhost_iotlb *iotlb, u64 start, u64 last,
 			  u64 addr, unsigned int perm);
 void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last);
 
+void vhost_iotlb_init(struct vhost_iotlb *iotlb, unsigned int limit,
+		      unsigned int flags);
 struct vhost_iotlb *vhost_iotlb_alloc(unsigned int limit, unsigned int flags);
 void vhost_iotlb_free(struct vhost_iotlb *iotlb);
 void vhost_iotlb_reset(struct vhost_iotlb *iotlb);
-- 
2.20.1