vhost: reset device properly

Currently, we reset all fields of a device to zero when reset
happens, which is wrong, since for some fields like device_fh,
ifname, and virt_qp_nb, they should be same and be kept after
reset until the device is removed. And this is what's the new
helper function reset_device() for.

And use rte_zmalloc() instead of rte_malloc, so that we could
avoid init_device(), which basically dose zero reset only so far.
Hence, init_device() is dropped in this patch.

This patch also removes a hack of using the offset a specific
field (which is virtqueue now) inside of `virtio_net' structure
to do reset, which could be broken easily if someone changed the
field order without caution.

Cc: Tetsuya Mukawa <mukawa@igel.co.jp>
Cc: Huawei Xie <huawei.xie@intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: Rich Lane <rich.lane@bigswitch.com>

diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
index 39a6a5e..cc917da 100644 (file)
--- a/lib/librte_vhost/virtio-net.c
+++ b/lib/librte_vhost/virtio-net.c
@@ -204,6 +204,7 @@ cleanup_device(struct virtio_net *dev)
                munmap((void *)(uintptr_t)dev->mem->mapped_address,
                        (size_t)dev->mem->mapped_size);
                free(dev->mem);
+               dev->mem = NULL;
        }
 
        for (i = 0; i < dev->virt_qp_nb; i++) {
@@ -306,20 +307,18 @@ alloc_vring_queue_pair(struct virtio_net *dev, uint32_t qp_idx)
 }
 
 /*
- *  Initialise all variables in device structure.
+ * Reset some variables in device structure, while keeping few
+ * others untouched, such as device_fh, ifname, virt_qp_nb: they
+ * should be same unless the device is removed.
  */
 static void
-init_device(struct virtio_net *dev)
+reset_device(struct virtio_net *dev)
 {
-       int vq_offset;
        uint32_t i;
 
-       /*
-        * Virtqueues have already been malloced so
-        * we don't want to set them to NULL.
-        */
-       vq_offset = offsetof(struct virtio_net, virtqueue);
-       memset(dev, 0, vq_offset);
+       dev->features = 0;
+       dev->protocol_features = 0;
+       dev->flags = 0;
 
        for (i = 0; i < dev->virt_qp_nb; i++)
                init_vring_queue_pair(dev, i);
@@ -336,7 +335,7 @@ new_device(struct vhost_device_ctx ctx)
        struct virtio_net_config_ll *new_ll_dev;
 
        /* Setup device and virtqueues. */
-       new_ll_dev = rte_malloc(NULL, sizeof(struct virtio_net_config_ll), 0);
+       new_ll_dev = rte_zmalloc(NULL, sizeof(struct virtio_net_config_ll), 0);
        if (new_ll_dev == NULL) {
                RTE_LOG(ERR, VHOST_CONFIG,
                        "(%"PRIu64") Failed to allocate memory for dev.\n",
@@ -344,9 +343,6 @@ new_device(struct vhost_device_ctx ctx)
                return -1;
        }
 
-       /* Initialise device and virtqueues. */
-       init_device(&new_ll_dev->dev);
-
        new_ll_dev->next = NULL;
 
        /* Add entry to device configuration linked list. */
@@ -430,7 +426,6 @@ static int
 reset_owner(struct vhost_device_ctx ctx)
 {
        struct virtio_net *dev;
-       uint64_t device_fh;
 
        dev = get_device(ctx);
        if (dev == NULL)
@@ -439,10 +434,8 @@ reset_owner(struct vhost_device_ctx ctx)
        if (dev->flags & VIRTIO_DEV_RUNNING)
                notify_ops->destroy_device(dev);
 
-       device_fh = dev->device_fh;
        cleanup_device(dev);
-       init_device(dev);
-       dev->device_fh = device_fh;
+       reset_device(dev);
        return 0;
 }