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authorDexuan Cui <decui@microsoft.com>2020-01-25 21:49:44 -0800
committerSasha Levin <sashal@kernel.org>2020-01-26 22:10:17 -0500
commit54e19d34011fea26d39aa74781131de0ce642a01 (patch)
tree3d0913466b3f1cc1f90338f44bc635d73d8809f0 /drivers/hv/hv_snapshot.c
parentffd1d4a49336b7f0078f45332fa4b93d25720f6c (diff)
hv_utils: Add the support of hibernation
Add util_pre_suspend() and util_pre_resume() for some hv_utils devices (e.g. kvp/vss/fcopy), because they need special handling before util_suspend() calls vmbus_close(). For kvp, all the possible pending work items should be cancelled. For vss and fcopy, some extra clean-up needs to be done, i.e. fake a THAW message for hv_vss_daemon and fake a CANCEL_FCOPY message for hv_fcopy_daemon, otherwise when the VM resums back, the daemons can end up in an inconsistent state (i.e. the file systems are frozen but will never be thawed; the file transmitted via fcopy may not be complete). Note: there is an extra patch for the daemons: "Tools: hv: Reopen the devices if read() or write() returns errors", because the hv_utils driver can not guarantee the whole transaction finishes completely once util_suspend() starts to run (at this time, all the userspace processes are frozen). util_probe() disables channel->callback_event to avoid the race with the channel callback. Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hv/hv_snapshot.c')
-rw-r--r--drivers/hv/hv_snapshot.c55
1 files changed, 53 insertions, 2 deletions
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 03b6454268b3..1c75b38f0d6d 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -379,10 +379,61 @@ hv_vss_init(struct hv_util_service *srv)
return 0;
}
-void hv_vss_deinit(void)
+static void hv_vss_cancel_work(void)
{
- vss_transaction.state = HVUTIL_DEVICE_DYING;
cancel_delayed_work_sync(&vss_timeout_work);
cancel_work_sync(&vss_handle_request_work);
+}
+
+int hv_vss_pre_suspend(void)
+{
+ struct vmbus_channel *channel = vss_transaction.recv_channel;
+ struct hv_vss_msg *vss_msg;
+
+ /*
+ * Fake a THAW message for the user space daemon in case the daemon
+ * has frozen the file systems. It doesn't matter if there is already
+ * a message pending to be delivered to the user space since we force
+ * vss_transaction.state to be HVUTIL_READY, so the user space daemon's
+ * write() will fail with EINVAL (see vss_on_msg()), and the daemon
+ * will reset the device by closing and re-opening it.
+ */
+ vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
+ if (!vss_msg)
+ return -ENOMEM;
+
+ tasklet_disable(&channel->callback_event);
+
+ vss_msg->vss_hdr.operation = VSS_OP_THAW;
+
+ /* Cancel any possible pending work. */
+ hv_vss_cancel_work();
+
+ /* We don't care about the return value. */
+ hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
+
+ kfree(vss_msg);
+
+ vss_transaction.state = HVUTIL_READY;
+
+ /* tasklet_enable() will be called in hv_vss_pre_resume(). */
+ return 0;
+}
+
+int hv_vss_pre_resume(void)
+{
+ struct vmbus_channel *channel = vss_transaction.recv_channel;
+
+ tasklet_enable(&channel->callback_event);
+
+ return 0;
+}
+
+void hv_vss_deinit(void)
+{
+ vss_transaction.state = HVUTIL_DEVICE_DYING;
+
+ hv_vss_cancel_work();
+
hvutil_transport_destroy(hvt);
}