script: add waitforbdev

The purpose is to control the time for test instead
of using sleep 1 or sheep 5when waiting for the ready
of bdevs.

Change-Id: I0319bcc270257612077da42024217d532cbc34e3
Signed-off-by: Ziye Yang <optimistyzy@gmail.com>
Reviewed-on: https://review.gerrithub.io/368264
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>

scripts/autotest_common.sh

@@ -194,6 +194,21 @@ function waitforlisten() {
 	set -x
 }
 
+function waitforbdev() {
+	bdev_name=$1
+	rpc_py=$2
+
+	for ((i=1; i<=10; i++)); do
+		if [ ! -z "`$rpc_py get_bdevs | grep $bdev_name`" ]; then
+			return 0
+		else
+			sleep 0.1
+		fi
+	done
+
+	return 1
+}
+
 function killprocess() {
 	# $1 = process pid
 	if [ -z "$1" ]; then