From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:55849) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QMiN7-0001UW-9Q for qemu-devel@nongnu.org; Wed, 18 May 2011 11:09:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QMiN1-0003uF-BH for qemu-devel@nongnu.org; Wed, 18 May 2011 11:09:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9018) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QMiN1-0003tp-2c for qemu-devel@nongnu.org; Wed, 18 May 2011 11:09:07 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p4IF96ug032233 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 18 May 2011 11:09:06 -0400 From: Gerd Hoffmann Date: Wed, 18 May 2011 17:08:58 +0200 Message-Id: <1305731343-27110-2-git-send-email-kraxel@redhat.com> In-Reply-To: <1305731343-27110-1-git-send-email-kraxel@redhat.com> References: <1305731343-27110-1-git-send-email-kraxel@redhat.com> Subject: [Qemu-devel] [PATCH 1/6] spice-qemu-char: Fix flow control in client -> guest direction List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Hans de Goede From: Hans de Goede 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(-) diff --git a/spice-qemu-char.c b/spice-qemu-char.c index fa15a71..605c241 100644 --- a/spice-qemu-char.c +++ b/spice-qemu-char.c @@ -36,14 +36,13 @@ 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); -- 1.7.1