diff --git a/src/bin/vhost_user_blk.rs b/src/bin/vhost_user_blk.rs
index a2b7b2224..c1e589770 100644
--- a/src/bin/vhost_user_blk.rs
+++ b/src/bin/vhost_user_blk.rs
@@ -23,11 +23,7 @@ fn main() {
         .arg(
             Arg::with_name("block-backend")
                 .long("block-backend")
-                .help(
-                    "vhost-user-block backend parameters \
-                     \"path=<image_path>,socket=<socket_path>,num_queues=<number_of_queues>,\
-                     readonly=true|false,direct=true|false,poll_queue=true|false\"",
-                )
+                .help(vhost_user_block::SYNTAX)
                 .takes_value(true)
                 .min_values(1),
         )
diff --git a/src/main.rs b/src/main.rs
index d757b0274..4b41903ce 100755
--- a/src/main.rs
+++ b/src/main.rs
@@ -243,11 +243,7 @@ fn create_app<'a, 'b>(
         .arg(
             Arg::with_name("block-backend")
                 .long("block-backend")
-                .help(
-                    "vhost-user-block backend parameters \
-                     \"path=<image_path>,socket=<socket_path>,num_queues=<number_of_queues>,\
-                     readonly=true|false,direct=true|false,poll_queue=true|false\"",
-                )
+                .help(vhost_user_block::SYNTAX)
                 .takes_value(true)
                 .conflicts_with_all(&["net-backend", "kernel"])
                 .min_values(1),
diff --git a/vhost_user_block/src/lib.rs b/vhost_user_block/src/lib.rs
index 35dee2cfa..f60638cf3 100644
--- a/vhost_user_block/src/lib.rs
+++ b/vhost_user_block/src/lib.rs
@@ -77,6 +77,10 @@ enum Error {
     HandleEventUnknownEvent,
 }
 
+pub const SYNTAX: &str = "vhost-user-block backend parameters \
+ \"path=<image_path>,socket=<socket_path>,num_queues=<number_of_queues>,\
+ readonly=true|false,direct=true|false,poll_queue=true|false\"";
+
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "vhost_user_block_error: {:?}", self)