migration: Drop multifd tls_hostname cache

The hostname is cached N times, N equals to the multifd channels.

Drop that cache because after previous patch we've got s->hostname
being alive for the whole lifecycle of migration procedure.

Cc: Juan Quintela <quintela@redhat.com>
Cc: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220331150857.74406-3-peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

migration/multifd.c

@@ -542,8 +542,6 @@ void multifd_save_cleanup(void)
         qemu_sem_destroy(&p->sem_sync);
         g_free(p->name);
         p->name = NULL;
-        g_free(p->tls_hostname);
-        p->tls_hostname = NULL;
         multifd_pages_clear(p->pages);
         p->pages = NULL;
         p->packet_len = 0;
@@ -763,7 +761,7 @@ static void multifd_tls_channel_connect(MultiFDSendParams *p,
                                         Error **errp)
 {
     MigrationState *s = migrate_get_current();
-    const char *hostname = p->tls_hostname;
+    const char *hostname = s->hostname;
     QIOChannelTLS *tioc;
 
     tioc = migration_tls_client_create(s, ioc, hostname, errp);
@@ -787,7 +785,8 @@ static bool multifd_channel_connect(MultiFDSendParams *p,
     MigrationState *s = migrate_get_current();
 
     trace_multifd_set_outgoing_channel(
-        ioc, object_get_typename(OBJECT(ioc)), p->tls_hostname, error);
+        ioc, object_get_typename(OBJECT(ioc)),
+        migrate_get_current()->hostname, error);
 
     if (!error) {
         if (s->parameters.tls_creds &&
@@ -874,7 +873,6 @@ int multifd_save_setup(Error **errp)
     int thread_count;
     uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
     uint8_t i;
-    MigrationState *s;
 
     if (!migrate_use_multifd()) {
         return 0;
@@ -884,7 +882,6 @@ int multifd_save_setup(Error **errp)
         return -1;
     }
 
-    s = migrate_get_current();
     thread_count = migrate_multifd_channels();
     multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
     multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
@@ -909,7 +906,6 @@ int multifd_save_setup(Error **errp)
         p->packet->magic = cpu_to_be32(MULTIFD_MAGIC);
         p->packet->version = cpu_to_be32(MULTIFD_VERSION);
         p->name = g_strdup_printf("multifdsend_%d", i);
-        p->tls_hostname = g_strdup(s->hostname);
         /* We need one extra place for the packet header */
         p->iov = g_new0(struct iovec, page_count + 1);
         p->normal = g_new0(ram_addr_t, page_count);

migration/multifd.h

@@ -72,8 +72,6 @@ typedef struct {
     uint8_t id;
     /* channel thread name */
     char *name;
-    /* tls hostname */
-    char *tls_hostname;
     /* channel thread id */
     QemuThread thread;
     /* communication channel */