buffered_file: do not send more than s->bytes_xfer bytes per tick

Sending more was possible if the buffer was large.

Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit bde54c08b4854aceee3dee25121a2b835cb81166)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/buffered_file.c b/buffered_file.c
index bd0f61d8c9684ca8347be8dfdc9d0619219613a5..9a8bd0446fcdda7cef7da52da96827e6d753a0b8 100644 (file)
--- a/buffered_file.c
+++ b/buffered_file.c
@@ -66,9 +66,9 @@ static ssize_t buffered_flush(QEMUFileBuffered *s)
     DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size);
 
     while (s->bytes_xfer < s->xfer_limit && offset < s->buffer_size) {
-
+        size_t to_send = MIN(s->buffer_size - offset, s->xfer_limit - s->bytes_xfer);
         ret = migrate_fd_put_buffer(s->migration_state, s->buffer + offset,
-                                    s->buffer_size - offset);
+                                    to_send);
         if (ret == -EAGAIN) {
             DPRINTF("backend not ready, freezing\n");
             ret = 0;