[PATCH v2 1/5] vduse: Add function to get/free the pages for reconnection

[Cindy Lu <lulu@redhat.com>]

Add the function vduse_alloc_reconnnect_info_mem
and vduse_alloc_reconnnect_info_mem
In this 2 function, vduse will get/free (vq_num + 1)*page  
Page 0 will be used to save the reconnection information, The
Userspace App will maintain this. Page 1 ~ vq_num + 1 will save
the reconnection information for vqs.

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 80 ++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 26b7e29cb900..6209e2f00278 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -41,6 +41,16 @@
 #define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
 #define VDUSE_MSG_DEFAULT_TIMEOUT 30
 
+/* struct vdpa_reconnect_info saved the alloc pages info
+ * these pages will mmaped to userspace for reconnection
+ */
+struct vdpa_reconnect_info {
+	/* Offset (within vm_file) in PAGE_SIZE */
+	u32 index;
+	/* virtual address for this page*/
+	unsigned long vaddr;
+};
+
 struct vduse_virtqueue {
 	u16 index;
 	u16 num_max;
@@ -57,6 +67,7 @@ struct vduse_virtqueue {
 	struct vdpa_callback cb;
 	struct work_struct inject;
 	struct work_struct kick;
+	struct vdpa_reconnect_info reconnect_info;
 };
 
 struct vduse_dev;
@@ -106,6 +117,7 @@ struct vduse_dev {
 	u32 vq_align;
 	struct vduse_umem *umem;
 	struct mutex mem_lock;
+	struct vdpa_reconnect_info reconnect_info;
 };
 
 struct vduse_dev_msg {
@@ -1030,6 +1042,64 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
 	return ret;
 }
 
+static int vduse_alloc_reconnnect_info_mem(struct vduse_dev *dev)
+{
+	struct vdpa_reconnect_info *info;
+	struct vduse_virtqueue *vq;
+
+	for (int i = 0; i < dev->vq_num + 1; i++) {
+		if (i == 0) {
+			/*page 0 is use to save status,Userland APP will use this to
+			 *save the information needed in reconnection,
+			 *kernel don't need to maintain this
+			 */
+			info = &dev->reconnect_info;
+			info->vaddr = get_zeroed_page(GFP_KERNEL);
+			if (info->vaddr == 0)
+				return -ENOMEM;
+			/* index is vm Offset in PAGE_SIZE */
+			info->index = 0;
+		}
+
+		/*page 1~ vq_num + 1 save the reconnect info for vq*/
+		vq = &dev->vqs[i];
+		info = &vq->reconnect_info;
+		info->vaddr = get_zeroed_page(GFP_KERNEL);
+		if (info->vaddr == 0)
+			return -ENOMEM;
+
+		info->index = i + 1;
+	}
+
+	return 0;
+}
+
+static int vduse_free_reconnnect_info_mem(struct vduse_dev *dev)
+{
+	struct vdpa_reconnect_info *info;
+	struct vduse_virtqueue *vq;
+
+	for (int i = 0; i < dev->vq_num + 1; i++) {
+		if (i == 0) {
+			info = &dev->reconnect_info;
+			if (info->vaddr)
+				free_page(info->vaddr);
+			info->index = 0;
+			info->vaddr = 0;
+		}
+
+		vq = &dev->vqs[i];
+		info = &vq->reconnect_info;
+
+		if (info->vaddr)
+			free_page(info->vaddr);
+		info->vaddr = 0;
+		info->index = 0;
+	}
+
+	return 0;
+}
+
 static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 			    unsigned long arg)
 {
@@ -1390,6 +1460,8 @@ static int vduse_destroy_dev(char *name)
 		mutex_unlock(&dev->lock);
 		return -EBUSY;
 	}
+	vduse_free_reconnnect_info_mem(dev);
+
 	dev->connected = true;
 	mutex_unlock(&dev->lock);
 
@@ -1542,9 +1614,17 @@ static int vduse_create_dev(struct vduse_dev_config *config,
 		ret = PTR_ERR(dev->dev);
 		goto err_dev;
 	}
+
+	ret = vduse_alloc_reconnnect_info_mem(dev);
+	if (ret < 0)
+		goto err_mem;
+
 	__module_get(THIS_MODULE);
 
 	return 0;
+
+err_mem:
+	vduse_free_reconnnect_info_mem(dev);
 err_dev:
 	idr_remove(&vduse_idr, dev->minor);
 err_idr:
-- 
2.34.3