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[Qemu-devel] [PATCH 5/6] char: change qemu_chr_fe_add_watch to return un
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 5/6] char: change qemu_chr_fe_add_watch to return unsigned |
Date: |
Mon, 20 Jun 2016 16:29:04 +0200 |
g_source_attach can return any value between 1 and UINT_MAX if you let
QEMU run long enough. However, qemu_chr_fe_add_watch can also return
a negative errno value when the device is disconnected or does not
support chr_add_watch. Change it to return zero to avoid overloading
these values.
Fix the cadence_uart which asserts in this case (easily obtained with
"-serial pty").
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/char/cadence_uart.c | 5 ++++-
include/sysemu/char.h | 16 ++++++++++++++--
qemu-char.c | 8 ++++----
3 files changed, 22 insertions(+), 7 deletions(-)
diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index c856fc3..488a570 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -294,7 +294,10 @@ static gboolean cadence_uart_xmit(GIOChannel *chan,
GIOCondition cond,
if (s->tx_count) {
int r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
cadence_uart_xmit, s);
- assert(r);
+ if (!r) {
+ s->tx_count = 0;
+ return FALSE;
+ }
}
uart_update_status(s);
diff --git a/include/sysemu/char.h b/include/sysemu/char.h
index 1eb2d0f..07434a0 100644
--- a/include/sysemu/char.h
+++ b/include/sysemu/char.h
@@ -221,8 +221,20 @@ void qemu_chr_fe_event(CharDriverState *s, int event);
void qemu_chr_fe_printf(CharDriverState *s, const char *fmt, ...)
GCC_FMT_ATTR(2, 3);
-int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
- GIOFunc func, void *user_data);
+/**
+ * @qemu_chr_fe_add_watch:
+ *
+ * If the backend is connected, create and add a #GSource that fires
+ * when the given condition (typically G_IO_OUT|G_IO_HUP or G_IO_HUP)
+ * is active; return the #GSource's tag. If it is disconnected,
+ * return 0.
+ *
+ * @cond the condition to poll for
+ * @func the function to call when the condition happens
+ * @user_data the opaque pointer to pass to @func
+ */
+unsigned qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
+ GIOFunc func, void *user_data);
/**
* @qemu_chr_fe_write:
diff --git a/qemu-char.c b/qemu-char.c
index 84f49ac..39b2ccd 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3966,19 +3966,19 @@ void qemu_chr_fe_event(struct CharDriverState *chr, int
event)
}
}
-int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
- GIOFunc func, void *user_data)
+unsigned qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
+ GIOFunc func, void *user_data)
{
GSource *src;
guint tag;
if (s->chr_add_watch == NULL) {
- return -ENOSYS;
+ return 0;
}
src = s->chr_add_watch(s, cond);
if (!src) {
- return -EINVAL;
+ return 0;
}
g_source_set_callback(src, (GSourceFunc)func, user_data, NULL);
--
2.5.5