migration: refactor: merge direct and p2p into unmanaged

p2p plain and direct function are good candidates for code reuse. Their main
function is same - to branch among different versions of migration protocol and
implementation of this function is also same. Also they have other common
functionality in lesser aspects. So let's merge them.

But as they have different signatures we have to get to convention on how to
pass direct migration 'uri' in 'dconnuri' and 'miguri'. Fortunately we alreay
have such convention in parameters passed to toURI2 function, just let's follow
it. 'uri' is passed in miguri and dconnuri is ignored.
Signed-off-by: NNikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>

src/libvirt-domain.c

@@ -3319,27 +3319,35 @@ virDomainMigrateCheckNotLocal(const char *dconnuri)
  * In normal migration, the libvirt client co-ordinates communication
  * between the 2 libvirtd instances on source & dest hosts.
  *
- * In this peer-2-peer migration alternative, the libvirt client
- * only talks to the source libvirtd instance. The source libvirtd
- * then opens its own connection to the destination and co-ordinates
- * migration itself.
+ * This function encapsulates 2 alternatives to the above case.
+ *
+ * 1. peer-2-peer migration, the libvirt client only talks to the source
+ * libvirtd instance. The source libvirtd then opens its own
+ * connection to the destination and co-ordinates migration itself.
+ *
+ * 2. direct migration, where there is no requirement for a libvirtd instance
+ * on the dest host. Eg, XenD can talk direct to XenD, so libvirtd on dest
+ * does not need to be involved at all, or even running.
  */
 static int
-virDomainMigratePeer2PeerPlain(virDomainPtr domain,
-                               const char *xmlin,
-                               unsigned int flags,
-                               const char *dname,
-                               const char *dconnuri,
-                               const char *miguri,
-                               unsigned long long bandwidth)
+virDomainMigrateUnmanaged(virDomainPtr domain,
+                          const char *xmlin,
+                          unsigned int flags,
+                          const char *dname,
+                          const char *dconnuri,
+                          const char *miguri,
+                          unsigned long long bandwidth)
 {
+    const char *uri = NULL;
+
     VIR_DOMAIN_DEBUG(domain,
                      "dconnuri=%s, xmlin=%s, dname=%s, migrui=%s, "
                      "bandwidth=%llu, flags=%x",
                      dconnuri, NULLSTR(xmlin), NULLSTR(dname), NULLSTR(miguri),
                      bandwidth, flags);
 
-    if (virDomainMigrateCheckNotLocal(dconnuri) < 0)
+    if ((flags & VIR_MIGRATE_PEER2PEER) &&
+        virDomainMigrateCheckNotLocal(dconnuri) < 0)
         return -1;
 
     if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
@@ -3364,13 +3372,18 @@ virDomainMigratePeer2PeerPlain(virDomainPtr domain,
                              "migration"));
             return -1;
         }
-        if (miguri) {
-            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("Unable to override peer2peer migration URI"));
-            return -1;
+        if (flags & VIR_MIGRATE_PEER2PEER) {
+            if (miguri) {
+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                               _("Unable to override peer2peer migration URI"));
+                return -1;
+            }
+            uri = dconnuri;
+        } else {
+            uri = miguri;
         }
         return domain->conn->driver->domainMigratePerform
-                (domain, NULL, 0, dconnuri, flags, dname, bandwidth);
+                (domain, NULL, 0, uri, flags, dname, bandwidth);
     }
 }
 
@@ -3401,75 +3414,6 @@ virDomainMigratePeer2PeerParams(virDomainPtr domain,
 }
 
 
-/*
- * In normal migration, the libvirt client co-ordinates communication
- * between the 2 libvirtd instances on source & dest hosts.
- *
- * Some hypervisors support an alternative, direct migration where
- * there is no requirement for a libvirtd instance on the dest host.
- * In this case
- *
- * eg, XenD can talk direct to XenD, so libvirtd on dest does not
- * need to be involved at all, or even running
- */
-static int
-virDomainMigrateDirect(virDomainPtr domain,
-                       const char *xmlin,
-                       unsigned long flags,
-                       const char *dname,
-                       const char *uri,
-                       unsigned long bandwidth)
-{
-    VIR_DOMAIN_DEBUG(domain,
-                     "xmlin=%s, flags=%lx, dname=%s, uri=%s, bandwidth=%lu",
-                     NULLSTR(xmlin), flags, NULLSTR(dname), NULLSTR(uri),
-                     bandwidth);
-
-    /* Perform the migration.  The driver isn't supposed to return
-     * until the migration is complete.
-     */
-    if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
-                                 VIR_DRV_FEATURE_MIGRATION_V3)) {
-        if (!domain->conn->driver->domainMigratePerform3) {
-            virReportUnsupportedError();
-            return -1;
-        }
-        VIR_DEBUG("Using migration protocol 3");
-        /* dconn URI not relevant in direct migration, since no
-         * target libvirtd is involved */
-        return domain->conn->driver->domainMigratePerform3(domain,
-                                                           xmlin,
-                                                           NULL, /* cookiein */
-                                                           0,    /* cookieinlen */
-                                                           NULL, /* cookieoutlen */
-                                                           NULL, /* cookieoutlen */
-                                                           NULL, /* dconnuri */
-                                                           uri,
-                                                           flags,
-                                                           dname,
-                                                           bandwidth);
-    } else {
-        if (!domain->conn->driver->domainMigratePerform) {
-            virReportUnsupportedError();
-            return -1;
-        }
-        VIR_DEBUG("Using migration protocol 2");
-        if (xmlin) {
-            virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
-                           _("Unable to change target guest XML during migration"));
-            return -1;
-        }
-        return domain->conn->driver->domainMigratePerform(domain,
-                                                          NULL, /* cookie */
-                                                          0,    /* cookielen */
-                                                          uri,
-                                                          flags,
-                                                          dname,
-                                                          bandwidth);
-    }
-}
-
-
 /**
  * virDomainMigrate:
  * @domain: a domain object
@@ -3607,8 +3551,8 @@ virDomainMigrate(virDomainPtr domain,
             }
 
             VIR_DEBUG("Using peer2peer migration");
-            if (virDomainMigratePeer2PeerPlain(domain, NULL, flags, dname,
-                                               uri ? uri : dstURI, NULL, bandwidth) < 0) {
+            if (virDomainMigrateUnmanaged(domain, NULL, flags, dname,
+                                          uri ? uri : dstURI, NULL, bandwidth) < 0) {
                 VIR_FREE(dstURI);
                 goto error;
             }
@@ -3828,8 +3772,8 @@ virDomainMigrate2(virDomainPtr domain,
                 return NULL;
 
             VIR_DEBUG("Using peer2peer migration");
-            if (virDomainMigratePeer2PeerPlain(domain, dxml, flags, dname,
-                                               dstURI, uri, bandwidth) < 0) {
+            if (virDomainMigrateUnmanaged(domain, dxml, flags, dname,
+                                          dstURI, uri, bandwidth) < 0) {
                 VIR_FREE(dstURI);
                 goto error;
             }
@@ -4209,8 +4153,8 @@ virDomainMigrateToURI(virDomainPtr domain,
         if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
                                      VIR_DRV_FEATURE_MIGRATION_P2P)) {
             VIR_DEBUG("Using peer2peer migration");
-            if (virDomainMigratePeer2PeerPlain(domain, NULL, flags,
-                                               dname, duri, NULL, bandwidth) < 0)
+            if (virDomainMigrateUnmanaged(domain, NULL, flags,
+                                          dname, duri, NULL, bandwidth) < 0)
                 goto error;
         } else {
             /* No peer to peer migration supported */
@@ -4221,8 +4165,8 @@ virDomainMigrateToURI(virDomainPtr domain,
         if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
                                      VIR_DRV_FEATURE_MIGRATION_DIRECT)) {
             VIR_DEBUG("Using direct migration");
-            if (virDomainMigrateDirect(domain, NULL, flags,
-                                       dname, duri, bandwidth) < 0)
+            if (virDomainMigrateUnmanaged(domain, NULL, flags,
+                                          dname, NULL, duri, bandwidth) < 0)
                 goto error;
         } else {
             /* Cannot do a migration with only the perform step */
@@ -4355,8 +4299,8 @@ virDomainMigrateToURI2(virDomainPtr domain,
         if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
                                      VIR_DRV_FEATURE_MIGRATION_P2P)) {
             VIR_DEBUG("Using peer2peer migration");
-            if (virDomainMigratePeer2PeerPlain(domain, dxml, flags,
-                                               dname, dconnuri, miguri, bandwidth) < 0)
+            if (virDomainMigrateUnmanaged(domain, dxml, flags,
+                                          dname, dconnuri, miguri, bandwidth) < 0)
                 goto error;
         } else {
             /* No peer to peer migration supported */
@@ -4367,8 +4311,8 @@ virDomainMigrateToURI2(virDomainPtr domain,
         if (VIR_DRV_SUPPORTS_FEATURE(domain->conn->driver, domain->conn,
                                      VIR_DRV_FEATURE_MIGRATION_DIRECT)) {
             VIR_DEBUG("Using direct migration");
-            if (virDomainMigrateDirect(domain, dxml, flags,
-                                       dname, miguri, bandwidth) < 0)
+            if (virDomainMigrateUnmanaged(domain, dxml, flags,
+                                          dname, NULL, miguri, bandwidth) < 0)
                 goto error;
         } else {
             /* Cannot do a migration with only the perform step */
@@ -4486,8 +4430,8 @@ virDomainMigrateToURI3(virDomainPtr domain,
                 goto error;
         } else if (compat) {
             VIR_DEBUG("Using peer2peer migration");
-            if (virDomainMigratePeer2PeerPlain(domain, dxml, flags, dname,
-                                               dconnuri, uri, bandwidth) < 0)
+            if (virDomainMigrateUnmanaged(domain, dxml, flags, dname,
+                                          dconnuri, uri, bandwidth) < 0)
                 goto error;
         } else {
             virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
@@ -4514,8 +4458,8 @@ virDomainMigrateToURI3(virDomainPtr domain,
         }
 
         VIR_DEBUG("Using direct migration");
-        if (virDomainMigrateDirect(domain, dxml, flags,
-                                   dname, uri, bandwidth) < 0)
+        if (virDomainMigrateUnmanaged(domain, dxml, flags,
+                                      dname, NULL, uri, bandwidth) < 0)
             goto error;
     }