From a162b5509dd20e21179ce091af0534d0320e1454 Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Fri, 4 Feb 2011 08:20:48 -0200 Subject: [RHEL6 qemu-kvm PATCH 17/27] char: Equip the unix/tcp backend to handle nonblocking writes RH-Author: Amit Shah Message-id: Patchwork-id: 17718 O-Subject: [RHEL6.1 qemu PATCH v5 17/19] char: Equip the unix/tcp backend to handle nonblocking writes Bugzilla: 588916 RH-Acked-by: Alon Levy RH-Acked-by: Juan Quintela RH-Acked-by: Jes Sorensen Now that the infrastructure is in place to return -EAGAIN to callers, individual char drivers can set their update_fd_handlers() function to set or remove an fd's write handler. This handler checks if the driver became writable. A generic callback routine is used for unblocking writes and letting users of chardevs know that a driver became writable again. Signed-off-by: Amit Shah --- qemu-char.c | 34 ++++++++++++++++++++++++++++++++++ 1 files changed, 34 insertions(+), 0 deletions(-) Signed-off-by: Eduardo Habkost --- qemu-char.c | 34 ++++++++++++++++++++++++++++++++++ 1 files changed, 34 insertions(+), 0 deletions(-) diff --git a/qemu-char.c b/qemu-char.c index 4d47189..dc3e930 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -108,6 +108,19 @@ static QTAILQ_HEAD(CharDriverStateHead, CharDriverState) chardevs = QTAILQ_HEAD_INITIALIZER(chardevs); +/* + * Generic routine that gets called when chardev becomes writable. + * Lets chardev user know it's OK to send more data. + */ +static void char_write_unblocked(void *opaque) +{ + CharDriverState *chr = opaque; + + chr->write_blocked = false; + chr->chr_disable_write_fd_handler(chr); + chr->chr_write_unblocked(chr->handler_opaque); +} + static void qemu_chr_event(CharDriverState *s, int event) { if (!s->chr_event) @@ -2247,6 +2260,25 @@ static void tcp_chr_close(CharDriverState *chr) qemu_chr_event(chr, CHR_EVENT_CLOSED); } +static void tcp_enable_write_fd_handler(CharDriverState *chr) +{ + TCPCharDriver *s = chr->opaque; + + /* + * This function is called only after tcp_chr_connect() is called + * (either in 'server' mode or client mode. So we're sure of + * s->fd being initialised. + */ + enable_write_fd_handler(s->fd, char_write_unblocked); +} + +static void tcp_disable_write_fd_handler(CharDriverState *chr) +{ + TCPCharDriver *s = chr->opaque; + + disable_write_fd_handler(s->fd); +} + static CharDriverState *qemu_chr_open_socket(QemuOpts *opts) { CharDriverState *chr = NULL; @@ -2299,6 +2331,8 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts *opts) chr->chr_write = tcp_chr_write; chr->chr_close = tcp_chr_close; chr->get_msgfd = tcp_get_msgfd; + chr->chr_enable_write_fd_handler = tcp_enable_write_fd_handler; + chr->chr_disable_write_fd_handler = tcp_disable_write_fd_handler; if (is_listen) { s->listen_fd = fd; -- 1.7.3.2