doc: fix a typo in prog guide

Signed-off-by: Yong Wang <wang.yong19@zte.com.cn>
Acked-by: John McNamara <john.mcnamara@intel.com>

diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index 4f997d4..f0862e6 100644 (file)
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -95,7 +95,7 @@ The following is an overview of the Vhost API functions:
     * for VM2NIC case, the ``nb_tx_desc`` has to be small enough: <= 64 if virtio
       indirect feature is not enabled and <= 128 if it is enabled.
 
     * for VM2NIC case, the ``nb_tx_desc`` has to be small enough: <= 64 if virtio
       indirect feature is not enabled and <= 128 if it is enabled.
 

-      The is because when dequeue zero copy is enabled, guest Tx used vring will
+      This is because when dequeue zero copy is enabled, guest Tx used vring will

       be updated only when corresponding mbuf is freed. Thus, the nb_tx_desc
       has to be small enough so that the PMD driver will run out of available
       Tx descriptors and free mbufs timely. Otherwise, guest Tx vring would be
       be updated only when corresponding mbuf is freed. Thus, the nb_tx_desc
       has to be small enough so that the PMD driver will run out of available
       Tx descriptors and free mbufs timely. Otherwise, guest Tx vring would be