From b3f1c8c413bc83e4a2cc7a63e4eddf9fe6449052 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 17 Oct 2017 20:11:58 +0200
Subject: [PATCH] qemu-pr-helper: use new libmultipath API

libmultipath has recently changed its API.  The new API supports multi-threaded
clients better.  Unfortunately there is no backwards-compatibility, so we just
switch to the new one.  Running QEMU compiled with the new library on the old
library will likely crash, while doing the opposite will cause QEMU not to
start at all (because udev, get_multipath_config and put_multipath_config
are undefined).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 configure             | 12 ++++++++++--
 scsi/qemu-pr-helper.c | 17 ++++++++++++++---
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/configure b/configure
index 6587e8014b..7766e74125 100755
--- a/configure
+++ b/configure
@@ -3312,9 +3312,17 @@ if test "$mpath" != "no" ; then
 #include <mpath_persist.h>
 unsigned mpath_mx_alloc_len = 1024;
 int logsink;
+static struct config *multipath_conf;
+extern struct udev *udev;
+extern struct config *get_multipath_config(void);
+extern void put_multipath_config(struct config *conf);
+struct udev *udev;
+struct config *get_multipath_config(void) { return multipath_conf; }
+void put_multipath_config(struct config *conf) { }
+
 int main(void) {
-    struct udev *udev = udev_new();
-    mpath_lib_init(udev);
+    udev = udev_new();
+    multipath_conf = mpath_lib_init();
     return 0;
 }
 EOF
diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
index d58184833f..dd9785143b 100644
--- a/scsi/qemu-pr-helper.c
+++ b/scsi/qemu-pr-helper.c
@@ -276,15 +276,26 @@ static void dm_init(void)
 
 /* Variables required by libmultipath and libmpathpersist.  */
 QEMU_BUILD_BUG_ON(PR_HELPER_DATA_SIZE > MPATH_MAX_PARAM_LEN);
+static struct config *multipath_conf;
 unsigned mpath_mx_alloc_len = PR_HELPER_DATA_SIZE;
 int logsink;
+struct udev *udev;
+
+extern struct config *get_multipath_config(void);
+struct config *get_multipath_config(void)
+{
+    return multipath_conf;
+}
+
+extern void put_multipath_config(struct config *conf);
+void put_multipath_config(struct config *conf)
+{
+}
 
 static void multipath_pr_init(void)
 {
-    static struct udev *udev;
-
     udev = udev_new();
-    mpath_lib_init(udev);
+    multipath_conf = mpath_lib_init();
 }
 
 static int is_mpath(int fd)