From e1590541a8c11139a534acdf41171ca24aabea5b Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Wed, 23 Mar 2011 09:40:40 -0300 Subject: [PATCH 08/16] spice-qemu-char: Fix flow control in client -> guest direction RH-Author: Hans de Goede Message-id: <1300873240-3732-2-git-send-email-hdegoede@redhat.com> Patchwork-id: 20471 O-Subject: [RHEL-6.1 PATCH] spice-qemu-char: Fix flow control in client -> guest direction Bugzilla: RH-Acked-by: Amit Shah RH-Acked-by: Uri Lublin RH-Acked-by: Alon Levy Bugzilla-related: 672191 In the old spice-vmc device we used to have: last_out = virtio_serial_write(&svc->port, p, MIN(len, VMC_MAX_HOST_WRITE)); if (last_out > 0) ... Now in the chardev backend we have: last_out = MIN(len, VMC_MAX_HOST_WRITE); qemu_chr_read(scd->chr, p, last_out); if (last_out > 0) { ... Which causes us to no longer detect if the virtio port is not ready to receive data from us. chardev actually has a mechanism to detect this, but it requires a separate call to qemu_chr_can_read, before calling qemu_chr_read (which return void). This patch uses qemu_chr_can_read to fix the flow control from client to guest. Signed-off-by: Hans de Goede --- spice-qemu-char.c | 11 +++++------ 1 files changed, 5 insertions(+), 6 deletions(-) Signed-off-by: Luiz Capitulino --- spice-qemu-char.c | 11 +++++------ 1 files changed, 5 insertions(+), 6 deletions(-) diff --git a/spice-qemu-char.c b/spice-qemu-char.c index 0e49cf1..454e9ad 100644 --- a/spice-qemu-char.c +++ b/spice-qemu-char.c @@ -37,14 +37,13 @@ static int vmc_write(SpiceCharDeviceInstance *sin, const uint8_t *buf, int len) while (len > 0) { last_out = MIN(len, VMC_MAX_HOST_WRITE); - qemu_chr_read(scd->chr, p, last_out); - if (last_out > 0) { - out += last_out; - len -= last_out; - p += last_out; - } else { + if (qemu_chr_can_read(scd->chr) < last_out) { break; } + qemu_chr_read(scd->chr, p, last_out); + out += last_out; + len -= last_out; + p += last_out; } dprintf(scd, 3, "%s: %lu/%zd\n", __func__, out, len + out); -- 1.7.4.1.230.gae447