| Message ID | 1272957442-7832-4-git-send-email-amit.shah@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 05/04/10 09:17, Amit Shah wrote: > Add a non-blocking write handler that can return with -EAGAIN to the > caller and also callback when the socket becomes writable. > > Non-blocking writes are only enabled for sockets that are opened in > non-blocking mode and only for callers that have registered a callback > handler for resuming writes. The logic will be pretty much the same for all filehandle-based backends on unix. So maybe create some helper functions, so implementing $backend_chr_write_unblocked can be done with just three lines of code? cheers, Gerd
On (Tue) May 04 2010 [09:43:04], Gerd Hoffmann wrote: > On 05/04/10 09:17, Amit Shah wrote: >> Add a non-blocking write handler that can return with -EAGAIN to the >> caller and also callback when the socket becomes writable. >> >> Non-blocking writes are only enabled for sockets that are opened in >> non-blocking mode and only for callers that have registered a callback >> handler for resuming writes. > > The logic will be pretty much the same for all filehandle-based backends > on unix. So maybe create some helper functions, so implementing > $backend_chr_write_unblocked can be done with just three lines of code? Yes, that's the next step. Let's push this for now and do that in a later patch series? Amit
On 05/04/10 09:56, Amit Shah wrote: >> The logic will be pretty much the same for all filehandle-based backends >> on unix. So maybe create some helper functions, so implementing >> $backend_chr_write_unblocked can be done with just three lines of code? > > Yes, that's the next step. Let's push this for now and do that in a > later patch series? Fine with me. cheers, Gerd
diff --git a/qemu-char.c b/qemu-char.c index 1cae1d2..476bb4e 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -2117,11 +2117,60 @@ static void tcp_chr_read(void *opaque) } } +static void tcp_chr_write_unblocked(void *opaque) +{ + CharDriverState *chr = opaque; + TCPCharDriver *s = chr->opaque; + + assert(chr->write_blocked && chr->chr_write_unblocked); + + chr->write_blocked = false; + qemu_set_fd_handler2(s->fd, tcp_chr_read_poll, tcp_chr_read, NULL, chr); + chr->chr_write_unblocked(chr->handler_opaque); +} + +static ssize_t tcp_chr_write_nb(CharDriverState *chr, const uint8_t *buf, + size_t len) +{ + TCPCharDriver *s = chr->opaque; + ssize_t ret; + + if (!s->connected) { + /* XXX: indicate an error? */ + return len; + } + + ret = send_all(s->fd, buf, len, true); + if (ret == -EAGAIN) { + chr->write_blocked = true; + qemu_set_fd_handler2(s->fd, tcp_chr_read_poll, + tcp_chr_read, tcp_chr_write_unblocked, chr); + } + return ret; +} + static void tcp_chr_connect(void *opaque) { CharDriverState *chr = opaque; TCPCharDriver *s = chr->opaque; + IOHandler *write_cb; + int flags; + bool nonblock; + + flags = fcntl(s->fd, F_GETFL); + if (flags == -1) { + flags = 0; + } + nonblock = flags & O_NONBLOCK; + + write_cb = NULL; + chr->nonblock = false; + if (nonblock && chr->chr_write_unblocked) { + write_cb = chr->chr_write_unblocked; + chr->nonblock = true; + } + chr->write_blocked = false; s->connected = 1; qemu_set_fd_handler2(s->fd, tcp_chr_read_poll, tcp_chr_read, NULL, chr); @@ -2254,6 +2303,7 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts *opts) chr->opaque = s; chr->chr_write = tcp_chr_write; + chr->chr_write_nb = tcp_chr_write_nb; chr->chr_close = tcp_chr_close; chr->get_msgfd = tcp_get_msgfd;
Add a non-blocking write handler that can return with -EAGAIN to the caller and also callback when the socket becomes writable. Non-blocking writes are only enabled for sockets that are opened in non-blocking mode and only for callers that have registered a callback handler for resuming writes. Signed-off-by: Amit Shah <amit.shah@redhat.com> --- qemu-char.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 50 insertions(+), 0 deletions(-)