From 6106261b0f1501a3772f4f9b67ae329697c7b815 Mon Sep 17 00:00:00 2001

From: Eduardo Habkost <ehabkost@redhat.com>

Date: Tue, 23 May 2017 13:43:59 +0200

Subject: [PATCH] char: change qemu_chr_fe_add_watch to return unsigned

RH-Author: Eduardo Habkost <ehabkost@redhat.com>

Message-id: <20170523134359.8747-1-ehabkost@redhat.com>

Patchwork-id: 75396

O-Subject: [RHEL-7.4 qemu-kvm PATCH] char: change qemu_chr_fe_add_watch to return unsigned

Bugzilla: 1451470

RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Paolo Bonzini <pbonzini@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1451470#c32

Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=13257025

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").

Backport Conflicts:

	hw/char/cadence_uart.c (no qemu_chr_fe_add_watch() call)

	net/vhost-user.c (doesn't exit)

	qemu-char.c (trivial conflict)

Tested-by: Bret Ketchum <bcketchum@gmail.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit 6f1de6b70d857d5e316ae6fd908f52818b827b08)

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 include/sysemu/char.h | 16 ++++++++++++++--

 qemu-char.c           |  8 ++++----

 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/include/sysemu/char.h b/include/sysemu/char.h

index ad101d9..c0e5b25 100644

--- a/include/sysemu/char.h

+++ b/include/sysemu/char.h

@@ -147,8 +147,20 @@ void qemu_chr_fe_set_open(struct CharDriverState *chr, int fe_open);

 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

+ */

+guint 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 08cb959..5edca0a 100644

--- a/qemu-char.c

+++ b/qemu-char.c

@@ -3373,19 +3373,19 @@ void qemu_chr_fe_set_open(struct CharDriverState *chr, int fe_open)

     }

 }

-int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,

-                          GIOFunc func, void *user_data)

+guint 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);

-- 

1.8.3.1