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call HotplugHandler->plug() as the last step in device realization

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When [2] was fixed it was agreed that adding and calling post_plug()
callback after device_reset() was low risk approach to hotfix issue
right before release. So it was merged instead of moving already
existing plug() callback after device_reset() is called which would
be more risky and require all plug() callbacks audit.

Looking at the current plug() callbacks, it doesn't seem that moving
plug() callback after device_reset() is breaking anything, so here
goes agreed upon [3] proper fix which essentially reverts [1][2]
and moves plug() callback after device_reset().
This way devices always comes to plug() stage, after it's been fully
initialized (including being reset), which fixes race condition [2]
without need for an extra post_plug() callback.

 1. (25e897881 "qdev: add HotplugHandler->post_plug() callback")
 2. (8449bcf94 "virtio-scsi: fix hotplug ->reset() vs event race")
 3. https://www.mail-archive.com/qemu-devel@nongnu.org/msg549915.html

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1539696820-273275-1-git-send-email-imammedo@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Pierre Morel<pmorel@linux.ibm.com>
Acked-by: Pierre Morel<pmorel@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Igor Mammedov 2018-10-16 15:33:40 +02:00 • committed by Paolo Bonzini
parent ac0989f53d
commit 8b5e6caf01
4 changed files with 7 additions and 41 deletions
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11
include/hw/hotplug.h
View file

@ -47,8 +47,6 @@ typedef void (*hotplug_fn)(HotplugHandler *plug_handler,
* @parent: Opaque parent interface.
* @pre_plug: pre plug callback called at start of device.realize(true)
* @plug: plug callback called at end of device.realize(true).
* @post_plug: post plug callback called after device.realize(true) and device
* reset
* @unplug_request: unplug request callback.
* Used as a means to initiate device unplug for devices that
* require asynchronous unplug handling.
@ -63,7 +61,6 @@ typedef struct HotplugHandlerClass {
/* <public> */
hotplug_fn pre_plug;
hotplug_fn plug;
void (*post_plug)(HotplugHandler *plug_handler, DeviceState *plugged_dev);
hotplug_fn unplug_request;
hotplug_fn unplug;
} HotplugHandlerClass;
@ -86,14 +83,6 @@ void hotplug_handler_pre_plug(HotplugHandler *plug_handler,
DeviceState *plugged_dev,
Error **errp);
/**
* hotplug_handler_post_plug:
*
* Call #HotplugHandlerClass.post_plug callback of @plug_handler.
*/
void hotplug_handler_post_plug(HotplugHandler *plug_handler,
DeviceState *plugged_dev);
/**
* hotplug_handler_unplug_request:
*