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Drivers: hv: vss: Introduce timeout for communication with userspace

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In contrast with KVP there is no timeout when communicating with
userspace VSS daemon. In case it gets stuck performing freeze/thaw
operation no message will be sent to the host so it will take very
long (around 10 minutes) before backup fails. Introduce 10 second
timeout using schedule_delayed_work().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vitaly Kuznetsov 2014-11-06 18:21:24 +01:00 committed by Greg Kroah-Hartman
parent 1a3c724afd
commit 649142074d
1 changed files with 18 additions and 2 deletions
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20
drivers/hv/hv_snapshot.c
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@ -28,7 +28,7 @@
#define VSS_MINOR 0
#define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR)
#define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))
/*
* Global state maintained for transaction that is being processed.
@ -55,12 +55,24 @@ static const char vss_name[] = "vss_kernel_module";
static __u8 *recv_buffer;
static void vss_send_op(struct work_struct *dummy);
static void vss_timeout_func(struct work_struct *dummy);
static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
static DECLARE_WORK(vss_send_op_work, vss_send_op);
/*
* Callback when data is received from user mode.
*/
static void vss_timeout_func(struct work_struct *dummy)
{
/*
* Timeout waiting for userspace component to reply happened.
*/
pr_warn("VSS: timeout waiting for daemon to reply\n");
vss_respond_to_host(HV_E_FAIL);
}
static void
vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
@ -76,7 +88,8 @@ vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
return;
}
vss_respond_to_host(vss_msg->error);
if (cancel_delayed_work_sync(&vss_timeout_work))
vss_respond_to_host(vss_msg->error);
}
@ -223,6 +236,8 @@ void hv_vss_onchannelcallback(void *context)
case VSS_OP_FREEZE:
case VSS_OP_THAW:
schedule_work(&vss_send_op_work);
schedule_delayed_work(&vss_timeout_work,
VSS_USERSPACE_TIMEOUT);
return;
case VSS_OP_HOT_BACKUP:
@ -277,5 +292,6 @@ hv_vss_init(struct hv_util_service *srv)
void hv_vss_deinit(void)
{
cn_del_callback(&vss_id);
cancel_delayed_work_sync(&vss_timeout_work);
cancel_work_sync(&vss_send_op_work);
}