migration: use QEMUFile for writing outgoing migration data

Second, drop the file descriptor indirection, and write directly to the
QEMUFile.

Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

include/migration/migration.h

@@ -40,10 +40,6 @@ struct MigrationState
     QEMUFile *file;
     QEMUFile *migration_file;
 
-    int fd;
-    int (*get_error)(MigrationState *s);
-    int (*write)(MigrationState *s, const void *buff, size_t size);
-
     int state;
     MigrationParams params;
     int64_t total_time;

migration-exec.c

@@ -33,16 +33,6 @@
     do { } while (0)
 #endif
 
-static int file_errno(MigrationState *s)
-{
-    return errno;
-}
-
-static int file_write(MigrationState *s, const void * buf, size_t size)
-{
-    return write(s->fd, buf, size);
-}
-
 void exec_start_outgoing_migration(MigrationState *s, const char *command, Error **errp)
 {
     s->migration_file = qemu_popen_cmd(command, "w");
@@ -51,8 +41,6 @@ void exec_start_outgoing_migration(MigrationState *s, const char *command, Error
         return;
     }
 
-    s->get_error = file_errno;
-    s->write = file_write;
     migrate_fd_connect(s);
 }
 

migration-fd.c

@@ -30,16 +30,6 @@
     do { } while (0)
 #endif
 
-static int fd_errno(MigrationState *s)
-{
-    return errno;
-}
-
-static int fd_write(MigrationState *s, const void * buf, size_t size)
-{
-    return write(s->fd, buf, size);
-}
-
 void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
 {
     int fd = monitor_get_fd(cur_mon, fdname, errp);
@@ -48,8 +38,6 @@ void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **
     }
     s->migration_file = qemu_fdopen(fd, "wb");
 
-    s->get_error = fd_errno;
-    s->write = fd_write;
     migrate_fd_connect(s);
 }
 

migration-tcp.c

@@ -29,16 +29,6 @@
     do { } while (0)
 #endif
 
-static int socket_errno(MigrationState *s)
-{
-    return socket_error();
-}
-
-static int socket_write(MigrationState *s, const void * buf, size_t size)
-{
-    return send(s->fd, buf, size, 0);
-}
-
 static void tcp_wait_for_connect(int fd, void *opaque)
 {
     MigrationState *s = opaque;
@@ -56,8 +46,6 @@ static void tcp_wait_for_connect(int fd, void *opaque)
 
 void tcp_start_outgoing_migration(MigrationState *s, const char *host_port, Error **errp)
 {
-    s->get_error = socket_errno;
-    s->write = socket_write;
     inet_nonblocking_connect(host_port, tcp_wait_for_connect, s, errp);
 }
 

migration-unix.c

@@ -29,16 +29,6 @@
     do { } while (0)
 #endif
 
-static int unix_errno(MigrationState *s)
-{
-    return errno;
-}
-
-static int unix_write(MigrationState *s, const void * buf, size_t size)
-{
-    return write(s->fd, buf, size);
-}
-
 static void unix_wait_for_connect(int fd, void *opaque)
 {
     MigrationState *s = opaque;
@@ -56,8 +46,6 @@ static void unix_wait_for_connect(int fd, void *opaque)
 
 void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp)
 {
-    s->get_error = unix_errno;
-    s->write = unix_write;
     unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
 }
 

migration.c

@@ -301,25 +301,6 @@ void migrate_fd_error(MigrationState *s)
     notifier_list_notify(&migration_state_notifiers, s);
 }
 
-static ssize_t migrate_fd_put_buffer(MigrationState *s, const void *data,
-                                     size_t size)
-{
-    ssize_t ret;
-
-    if (s->state != MIG_STATE_ACTIVE) {
-        return -EIO;
-    }
-
-    do {
-        ret = s->write(s, data, size);
-    } while (ret == -1 && ((s->get_error(s)) == EINTR));
-
-    if (ret == -1)
-        ret = -(s->get_error(s));
-
-    return ret;
-}
-
 static void migrate_fd_cancel(MigrationState *s)
 {
     DPRINTF("cancelling migration\n");
@@ -333,7 +314,6 @@ int migrate_fd_close(MigrationState *s)
     if (s->migration_file != NULL) {
         rc = qemu_fclose(s->migration_file);
         s->migration_file = NULL;
-        s->fd = -1;
     }
     return rc;
 }
@@ -519,8 +499,7 @@ static int migration_put_buffer(void *opaque, const uint8_t *buf,
                                int64_t pos, int size)
 {
     MigrationState *s = opaque;
-    ssize_t ret;
+    int ret;
-    size_t sent;
 
     DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos);
 
@@ -528,22 +507,14 @@ static int migration_put_buffer(void *opaque, const uint8_t *buf,
         return size;
     }
 
-    sent = 0;
+    qemu_put_buffer(s->migration_file, buf, size);
-    while (size) {
+    ret = qemu_file_get_error(s->migration_file);
-        ret = migrate_fd_put_buffer(s, buf, size);
+    if (ret) {
-        if (ret <= 0) {
+        return ret;
-            DPRINTF("error flushing data, %zd\n", ret);
-            return ret;
-        } else {
-            DPRINTF("flushed %zd byte(s)\n", ret);
-            sent += ret;
-            buf += ret;
-            size -= ret;
-            s->bytes_xfer += ret;
-        }
     }
 
-    return sent;
+    s->bytes_xfer += size;
+    return size;
 }
 
 static int migration_close(void *opaque)
@@ -564,7 +535,7 @@ static int migration_get_fd(void *opaque)
 {
     MigrationState *s = opaque;
 
-    return s->fd;
+    return qemu_get_fd(s->migration_file);
 }
 
 /*
@@ -721,7 +692,6 @@ void migrate_fd_connect(MigrationState *s)
     s->xfer_limit = s->bandwidth_limit / XFER_LIMIT_RATIO;
 
     s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
-    s->fd = qemu_get_fd(s->migration_file);
     s->file = qemu_fopen_ops(s, &migration_file_ops);
 
     qemu_thread_create(&s->thread, migration_thread, s,