qdev: Replace no_user by cannot_instantiate_with_device_add_yet

In an ideal world, machines can be built by wiring devices together
with configuration, not code.  Unfortunately, that's not the world we
live in right now.  We still have quite a few devices that need to be
wired up by code.  If you try to device_add such a device, it'll fail
in sometimes mysterious ways.  If you're lucky, you get an
unmysterious immediate crash.

To protect users from such badness, DeviceClass member no_user used to
make device models unavailable with -device / device_add, but that
regressed in commit 18b6dad.  The device model is still omitted from
help, but is available anyway.

Attempts to fix the regression have been rejected with the argument
that the purpose of no_user isn't clear, and it's prone to misuse.

This commit clarifies no_user's purpose.  Anthony suggested to rename
it cannot_instantiate_with_device_add_yet_due_to_internal_bugs, which
I shorten somewhat to keep checkpatch happy.  While there, make it
bool.

Every use of cannot_instantiate_with_device_add_yet gets a FIXME
comment asking for rationale.  The next few commits will clean them
all up, either by providing a rationale, or by getting rid of the use.

With that done, the regression fix is hopefully acceptable.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

6 files changed, 6 insertions, 6 deletions

diff --git a/hw/timer/arm_mptimer.c b/hw/timer/arm_mptimer.c
index d9f9494f26..1dc44cd3d1 100644
--- a/hw/timer/arm_mptimer.c
+++ b/hw/timer/arm_mptimer.c
@@ -274,7 +274,7 @@ static void arm_mptimer_class_init(ObjectClass *klass, void *data)
     dc->realize = arm_mptimer_realize;
     dc->vmsd = &vmstate_arm_mptimer;
     dc->reset = arm_mptimer_reset;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->props = arm_mptimer_properties;
 }
 
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index bb3bf98745..74e0297f82 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -765,7 +765,7 @@ static void hpet_device_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = hpet_realize;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->reset = hpet_reset;
     dc->vmsd = &vmstate_hpet;
     dc->props = hpet_device_properties;
diff --git a/hw/timer/i8254_common.c b/hw/timer/i8254_common.c
index e8fb971488..dc2196c1ef 100644
--- a/hw/timer/i8254_common.c
+++ b/hw/timer/i8254_common.c
@@ -282,7 +282,7 @@ static void pit_common_class_init(ObjectClass *klass, void *data)
 
     dc->realize = pit_common_realize;
     dc->vmsd = &vmstate_pit_common;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo pit_common_type = {
diff --git a/hw/timer/m48t59.c b/hw/timer/m48t59.c
index be0592b53d..e079d41818 100644
--- a/hw/timer/m48t59.c
+++ b/hw/timer/m48t59.c
@@ -750,7 +750,7 @@ static void m48t59_isa_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = m48t59_isa_realize;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->reset = m48t59_reset_isa;
     dc->props = m48t59_isa_properties;
 }
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index b0116381c0..ad61e2cffb 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -899,7 +899,7 @@ static void rtc_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = rtc_realizefn;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_rtc;
     dc->props = mc146818rtc_properties;
 }
diff --git a/hw/timer/pl031.c b/hw/timer/pl031.c
index 65928a4819..2f7360cab9 100644
--- a/hw/timer/pl031.c
+++ b/hw/timer/pl031.c
@@ -251,7 +251,7 @@ static void pl031_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = pl031_init;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_pl031;
 }