From 649142074d86afebe0505431a93957505d244dd6 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Thu, 6 Nov 2014 18:21:24 +0100 Subject: Drivers: hv: vss: Introduce timeout for communication with userspace 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 Signed-off-by: Greg Kroah-Hartman --- drivers/hv/hv_snapshot.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) (limited to 'drivers/hv/hv_snapshot.c') diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c index 34f14fd..21e51be 100644 --- a/drivers/hv/hv_snapshot.c +++ b/drivers/hv/hv_snapshot.c @@ -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); } -- cgit v1.1