From f32ee7f16206334c90d2c92517617c08f436ca97 Mon Sep 17 00:00:00 2001

From: Stefan Hajnoczi <stefanha@redhat.com>

Date: Tue, 16 Jul 2019 13:22:13 +0200

Subject: [PATCH 20/23] vl: add qemu_add_vm_change_state_handler_prio()

RH-Author: Stefan Hajnoczi <stefanha@redhat.com>

Message-id: <20190716132215.18503-2-stefanha@redhat.com>

Patchwork-id: 89536

O-Subject: [RHEL-7.8 RHEL-7.7.z qemu-kvm-rhev PATCH 1/3] vl: add qemu_add_vm_change_state_handler_prio()

Bugzilla: 1673546

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

RH-Acked-by: John Snow <jsnow@redhat.com>

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

Add an API for registering vm change state handlers with a well-defined

ordering.  This is necessary when handlers depend on each other.

Small coding style fixes are included to make checkpatch.pl happy.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit 60dbc5a1c5176269669ffc26c081ab2cfb7f12f7)

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

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

Conflicts:

  vl.c

  The QTAILQ macros require an explicit name for the head type.

---

 include/sysemu/sysemu.h |  2 ++

 vl.c                    | 61 +++++++++++++++++++++++++++++++++++++++----------

 2 files changed, 51 insertions(+), 12 deletions(-)

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

index 2a6f4a5..723c7a9 100644

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

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

@@ -29,6 +29,8 @@ typedef void VMChangeStateHandler(void *opaque, int running, RunState state);

 VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb,

                                                      void *opaque);

+VMChangeStateEntry *qemu_add_vm_change_state_handler_prio(

+        VMChangeStateHandler *cb, void *opaque, int priority);

 void qemu_del_vm_change_state_handler(VMChangeStateEntry *e);

 void vm_state_notify(int running, RunState state);

diff --git a/vl.c b/vl.c

index 5b337e1..6529d68 100644

--- a/vl.c

+++ b/vl.c

@@ -1658,28 +1658,58 @@ static int machine_help_func(QemuOpts *opts, MachineState *machine)

 struct vm_change_state_entry {

     VMChangeStateHandler *cb;

     void *opaque;

-    QLIST_ENTRY (vm_change_state_entry) entries;

+    QTAILQ_ENTRY(vm_change_state_entry) entries;

+    int priority;

 };

-static QLIST_HEAD(vm_change_state_head, vm_change_state_entry) vm_change_state_head;

+static QTAILQ_HEAD(VMChangeStateHead,

+                   vm_change_state_entry) vm_change_state_head;

-VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb,

-                                                     void *opaque)

+/**

+ * qemu_add_vm_change_state_handler_prio:

+ * @cb: the callback to invoke

+ * @opaque: user data passed to the callback

+ * @priority: low priorities execute first when the vm runs and the reverse is

+ *            true when the vm stops

+ *

+ * Register a callback function that is invoked when the vm starts or stops

+ * running.

+ *

+ * Returns: an entry to be freed using qemu_del_vm_change_state_handler()

+ */

+VMChangeStateEntry *qemu_add_vm_change_state_handler_prio(

+        VMChangeStateHandler *cb, void *opaque, int priority)

 {

     VMChangeStateEntry *e;

+    VMChangeStateEntry *other;

-    e = g_malloc0(sizeof (*e));

-

+    e = g_malloc0(sizeof(*e));

     e->cb = cb;

     e->opaque = opaque;

-    QLIST_INSERT_HEAD(&vm_change_state_head, e, entries);

+    e->priority = priority;

+

+    /* Keep list sorted in ascending priority order */

+    QTAILQ_FOREACH(other, &vm_change_state_head, entries) {

+        if (priority < other->priority) {

+            QTAILQ_INSERT_BEFORE(other, e, entries);

+            return e;

+        }

+    }

+

+    QTAILQ_INSERT_TAIL(&vm_change_state_head, e, entries);

     return e;

 }

+VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb,

+                                                     void *opaque)

+{

+    return qemu_add_vm_change_state_handler_prio(cb, opaque, 0);

+}

+

 void qemu_del_vm_change_state_handler(VMChangeStateEntry *e)

 {

-    QLIST_REMOVE (e, entries);

-    g_free (e);

+    QTAILQ_REMOVE(&vm_change_state_head, e, entries);

+    g_free(e);

 }

 void vm_state_notify(int running, RunState state)

@@ -1688,8 +1718,15 @@ void vm_state_notify(int running, RunState state)

     trace_vm_state_notify(running, state);

-    QLIST_FOREACH_SAFE(e, &vm_change_state_head, entries, next) {

-        e->cb(e->opaque, running, state);

+    if (running) {

+        QTAILQ_FOREACH_SAFE(e, &vm_change_state_head, entries, next) {

+            e->cb(e->opaque, running, state);

+        }

+    } else {

+        QTAILQ_FOREACH_REVERSE_SAFE(e, &vm_change_state_head,

+                                    VMChangeStateHead, entries, next) {

+            e->cb(e->opaque, running, state);

+        }

     }

 }

@@ -3194,7 +3231,7 @@ int main(int argc, char **argv, char **envp)

     }

     rtc_clock = QEMU_CLOCK_HOST;

-    QLIST_INIT (&vm_change_state_head);

+    QTAILQ_INIT(&vm_change_state_head);

     os_setup_early_signal_handling();

     cpu_model = NULL;

-- 

1.8.3.1