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[PATCH 74/97] xen-bus: Fix backend state transition on device reset
From: |
Michael Roth |
Subject: |
[PATCH 74/97] xen-bus: Fix backend state transition on device reset |
Date: |
Tue, 1 Oct 2019 18:45:53 -0500 |
From: Anthony PERARD <address@hidden>
When a frontend wants to reset its state and the backend one, it
starts with setting "Closing", then waits for the backend (QEMU) to do
the same.
But when QEMU is setting "Closing" to its state, it triggers an event
(xenstore watch) that re-execute xen_device_backend_changed() and set
the backend state to "Closed". QEMU should wait for the frontend to
set "Closed" before doing the same.
Before setting "Closed" to the backend_state, we are also going to
check if there is a frontend. If that the case, when the backend state
is set to "Closing" the frontend should react and sets its state to
"Closing" then "Closed". The backend should wait for that to happen.
Fixes: b6af8926fb858c4f1426e5acb2cfc1f0580ec98a
Signed-off-by: Anthony PERARD <address@hidden>
Reviewed-by: Paul Durrant <address@hidden>
Message-Id: <address@hidden>
(cherry picked from commit cb3231460747552d70af9d546dc53d8195bcb796)
Signed-off-by: Michael Roth <address@hidden>
---
hw/xen/xen-bus.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index 49a725e8c7..0a1033d9a9 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -515,6 +515,23 @@ static void xen_device_backend_set_online(XenDevice
*xendev, bool online)
xen_device_backend_printf(xendev, "online", "%u", online);
}
+/*
+ * Tell from the state whether the frontend is likely alive,
+ * i.e. it will react to a change of state of the backend.
+ */
+static bool xen_device_state_is_active(enum xenbus_state state)
+{
+ switch (state) {
+ case XenbusStateInitWait:
+ case XenbusStateInitialised:
+ case XenbusStateConnected:
+ case XenbusStateClosing:
+ return true;
+ default:
+ return false;
+ }
+}
+
static void xen_device_backend_changed(void *opaque)
{
XenDevice *xendev = opaque;
@@ -538,11 +555,11 @@ static void xen_device_backend_changed(void *opaque)
/*
* If the toolstack (or unplug request callback) has set the backend
- * state to Closing, but there is no active frontend (i.e. the
- * state is not Connected) then set the backend state to Closed.
+ * state to Closing, but there is no active frontend then set the
+ * backend state to Closed.
*/
if (xendev->backend_state == XenbusStateClosing &&
- xendev->frontend_state != XenbusStateConnected) {
+ !xen_device_state_is_active(state)) {
xen_device_backend_set_state(xendev, XenbusStateClosed);
}
--
2.17.1
- [PATCH 84/97] block/nfs: tear down aio before nfs_close, (continued)
- [PATCH 84/97] block/nfs: tear down aio before nfs_close, Michael Roth, 2019/10/01
- [PATCH 92/97] curl: Check curl_multi_add_handle()'s return code, Michael Roth, 2019/10/01
- [PATCH 10/97] spapr/xive: fix EQ page addresses above 64GB, Michael Roth, 2019/10/01
- [PATCH 06/97] block: Fix AioContext switch for bs->drv == NULL, Michael Roth, 2019/10/01
- [PATCH 96/97] hw/core/loader: Fix possible crash in rom_copy(), Michael Roth, 2019/10/01
- [PATCH 93/97] slirp: Fix heap overflow in ip_reass on big packet input, Michael Roth, 2019/10/01
- [PATCH 95/97] s390: PCI: fix IOMMU region init, Michael Roth, 2019/10/01
- [PATCH 63/97] backup: Copy only dirty areas, Michael Roth, 2019/10/01
- [PATCH 08/97] Makefile: add nit-picky mode to sphinx-build, Michael Roth, 2019/10/01
- [PATCH 97/97] scsi: lsi: exit infinite loop while executing script (CVE-2019-12068), Michael Roth, 2019/10/01
- [PATCH 74/97] xen-bus: Fix backend state transition on device reset,
Michael Roth <=
- [PATCH 75/97] pr-manager: Fix invalid g_free() crash bug, Michael Roth, 2019/10/01
- [PATCH 94/97] slirp: ip_reass: Fix use after free, Michael Roth, 2019/10/01
- [PATCH 09/97] docs/interop/bitmaps: rewrite and modernize doc, Michael Roth, 2019/10/01
- [PATCH 23/97] iotests: add iotest 256 for testing blockdev-backup across iothread contexts, Michael Roth, 2019/10/01
- [PATCH 91/97] curl: Handle success in multi_check_completion, Michael Roth, 2019/10/01
- [PATCH 19/97] iotests.py: do not use infinite waits, Michael Roth, 2019/10/01
- Re: [PATCH 00/97] Patch Round-up for stable 4.0.1, freeze on 2019-10-10, Thomas Huth, 2019/10/02
- Re: [PATCH 00/97] Patch Round-up for stable 4.0.1, freeze on 2019-10-10, Philippe Mathieu-Daudé, 2019/10/03
- Re: [PATCH 00/97] Patch Round-up for stable 4.0.1, freeze on 2019-10-10, Alexandr Iarygin, 2019/10/07