[PATCH v4 21/34] migration/multifd: Add incoming QIOChannelFile support

[Fabiano Rosas <farosas@suse.de>]

On the receiving side we don't need to differentiate between main
channel and threads, so whichever channel is defined first gets to be
the main one. And since there are no packets, use the atomic channel
count to index into the params array.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 migration/file.c      | 34 ++++++++++++++++++++++++++--------
 migration/migration.c |  3 ++-
 migration/multifd.c   |  3 +--
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/migration/file.c b/migration/file.c
index ac9f6ae40a..a186dc592a 100644
--- a/migration/file.c
+++ b/migration/file.c
@@ -8,6 +8,7 @@
 #include "qemu/osdep.h"
 #include "exec/ramblock.h"
 #include "qemu/cutils.h"
+#include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "channel.h"
 #include "file.h"
@@ -15,6 +16,7 @@
 #include "multifd.h"
 #include "io/channel-file.h"
 #include "io/channel-util.h"
+#include "options.h"
 #include "trace.h"
 
 #define OFFSET_OPTION ",offset="
@@ -111,7 +113,8 @@ void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp)
     g_autofree char *filename = g_strdup(file_args->filename);
     QIOChannelFile *fioc = NULL;
     uint64_t offset = file_args->offset;
-    QIOChannel *ioc;
+    int channels = 1;
+    int i = 0, fd;
 
     trace_migration_file_incoming(filename);
 
@@ -120,13 +123,28 @@ void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp)
         return;
     }
 
-    ioc = QIO_CHANNEL(fioc);
-    if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
+    if (offset &&
+        qio_channel_io_seek(QIO_CHANNEL(fioc), offset, SEEK_SET, errp) < 0) {
         return;
     }
-    qio_channel_set_name(QIO_CHANNEL(ioc), "migration-file-incoming");
-    qio_channel_add_watch_full(ioc, G_IO_IN,
-                               file_accept_incoming_migration,
-                               NULL, NULL,
-                               g_main_context_get_thread_default());
+
+    if (migrate_multifd()) {
+        channels += migrate_multifd_channels();
+    }
+
+    fd = fioc->fd;
+
+    do {
+        QIOChannel *ioc = QIO_CHANNEL(fioc);
+
+        qio_channel_set_name(ioc, "migration-file-incoming");
+        qio_channel_add_watch_full(ioc, G_IO_IN,
+                                   file_accept_incoming_migration,
+                                   NULL, NULL,
+                                   g_main_context_get_thread_default());
+    } while (++i < channels && (fioc = qio_channel_file_new_fd(fd)));
+
+    if (!fioc) {
+        error_setg(errp, "Error creating migration incoming channel");
+    }
 }
diff --git a/migration/migration.c b/migration/migration.c
index 16da269847..e2218b9de7 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -896,7 +896,8 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
     uint32_t channel_magic = 0;
     int ret = 0;
 
-    if (migrate_multifd() && !migrate_postcopy_ram() &&
+    if (migrate_multifd() && !migrate_fixed_ram() &&
+        !migrate_postcopy_ram() &&
         qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_READ_MSG_PEEK)) {
         /*
          * With multiple channels, it is possible that we receive channels
diff --git a/migration/multifd.c b/migration/multifd.c
index 507b497d52..cb5f4fb3e0 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -1520,8 +1520,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
         }
         trace_multifd_recv_new_channel(id);
     } else {
-        /* next patch gives this a meaningful value */
-        id = 0;
+        id = qatomic_read(&multifd_recv_state->count);
     }
 
     p = &multifd_recv_state->params[id];
-- 
2.35.3