QIOChannelRDMA's readv already blocks inside qemu_rdma_exchange_recv() when waiting for the next RDMA SEND message. What it did not do was keep blocking when the bytes from a single receive were insufficient to satisfy the full request -- it returned partial data (or EAGAIN) instead of waiting for more.
Loop on qemu_rdma_exchange_recv() when the channel is blocking and the receive buffer cannot satisfy the request. This matches the behaviour of other QIOChannel implementations, which block until the full request is satisfied (or an error occurs). Also remove the stale XXX comments about unimplemented blocking support. Reviewed-by: Li Zhijian <[email protected]> Signed-off-by: Bin Guo <[email protected]> --- migration/rdma.c | 46 +++++++++++++++++++++------------------------- 1 file changed, 21 insertions(+), 25 deletions(-) diff --git a/migration/rdma.c b/migration/rdma.c index 3e37a1d440..201cb9eb12 100644 --- a/migration/rdma.c +++ b/migration/rdma.c @@ -388,7 +388,7 @@ struct QIOChannelRDMA { QIOChannel parent; RDMAContext *rdmain; RDMAContext *rdmaout; - bool blocking; /* XXX we don't actually honour this yet */ + bool blocking; }; /* @@ -2710,32 +2710,29 @@ static ssize_t qio_channel_rdma_readv(QIOChannel *ioc, break; } - - /* We've got nothing at all, so lets wait for - * more to arrive - */ - ret = qemu_rdma_exchange_recv(rdma, &head, RDMA_CONTROL_QEMU_FILE, - errp); - - if (ret < 0) { - rdma->errored = true; - return -1; - } - /* - * SEND was received with new bytes, now try again. + * We've got nothing at all, so lets wait for + * more to arrive. */ - len = qemu_rdma_fill(rdma, data, want, 0); - done += len; - want -= len; - - /* Still didn't get enough, so lets just return */ - if (want) { - if (done == 0) { - return QIO_CHANNEL_ERR_BLOCK; - } else { - break; + do { + ret = qemu_rdma_exchange_recv(rdma, &head, + RDMA_CONTROL_QEMU_FILE, errp); + if (ret < 0) { + rdma->errored = true; + return -1; } + + /* + * SEND was received with new bytes, now try again. + */ + len = qemu_rdma_fill(rdma, data, want, 0); + done += len; + want -= len; + data += len; + } while (want && rioc->blocking); + + if (want && done == 0) { + return QIO_CHANNEL_ERR_BLOCK; } } return done; @@ -2771,7 +2768,6 @@ static int qio_channel_rdma_set_blocking(QIOChannel *ioc, Error **errp) { QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(ioc); - /* XXX we should make readv/writev actually honour this :-) */ rioc->blocking = blocking; return 0; } -- 2.50.1 (Apple Git-155)
