[3/5] char: Add framework for a 'write unblocked' callback

Submitted by Amit Shah on Jan. 11, 2011, 11:10 a.m.

Details

Message ID 3b7fddd6f8538bfdcb01f46935f4fc0760296ea6.1294743490.git.amit.shah@redhat.com
State New
Headers show

Commit Message

Amit Shah Jan. 11, 2011, 11:10 a.m.
The char layer can let users know that the driver will block on further
input.  For users interested in not blocking, they can assign a function
pointer that will be called back when the driver becomes writable.  This
patch just adds the function pointers to the CharDriverState structure,
future patches will enable the nonblocking and callback functionality.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 qemu-char.c |    3 +++
 qemu-char.h |    5 +++++
 2 files changed, 8 insertions(+), 0 deletions(-)

Comments

Gerd Hoffmann Jan. 11, 2011, 2:43 p.m.
Hi,

> @@ -60,6 +60,9 @@ struct CharDriverState {
>       IOEventHandler *chr_event;
>       IOCanReadHandler *chr_can_read;
>       IOReadHandler *chr_read;
> +    IOHandler *chr_write_unblocked;
> +    void (*update_fd_handlers)(struct CharDriverState *chr,
> +                               bool poll_out);

I think you don't need that callback in the first place if you are able 
to just enable/disable the handlers for a file handle.

cheers,
   Gerd

Patch hide | download patch | download mbox

diff --git a/qemu-char.c b/qemu-char.c
index 2420b6b..9a132b6 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -202,11 +202,14 @@  void qemu_chr_add_handlers(CharDriverState *s,
     }
     s->chr_can_read = handlers->fd_can_read;
     s->chr_read = handlers->fd_read;
+    s->chr_write_unblocked = handlers->fd_write_unblocked;
     s->chr_event = handlers->fd_event;
     s->handler_opaque = opaque;
     if (s->chr_update_read_handler)
         s->chr_update_read_handler(s);
 
+    s->write_blocked = false;
+
     /* We're connecting to an already opened device, so let's make sure we
        also get the open event */
     if (s->opened) {
diff --git a/qemu-char.h b/qemu-char.h
index 8ed0ffd..0c2c445 100644
--- a/qemu-char.h
+++ b/qemu-char.h
@@ -60,6 +60,9 @@  struct CharDriverState {
     IOEventHandler *chr_event;
     IOCanReadHandler *chr_can_read;
     IOReadHandler *chr_read;
+    IOHandler *chr_write_unblocked;
+    void (*update_fd_handlers)(struct CharDriverState *chr,
+                               bool poll_out);
     void *handler_opaque;
     void (*chr_send_event)(struct CharDriverState *chr, int event);
     void (*chr_close)(struct CharDriverState *chr);
@@ -69,6 +72,8 @@  struct CharDriverState {
     char *label;
     char *filename;
     int opened;
+    /* Are we in a blocked state? */
+    bool write_blocked;
     QTAILQ_ENTRY(CharDriverState) next;
 };