From: Vivek yadav <vya...@microsoft.com>
Under stress, we have seen allocation failure in time synch code. Avoid
this dynamic allocation.
Signed-off-by: Vivek Yadav <vya...@microsoft.com>
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
---
drivers/hv/hv_util.c | 39 ++++++++++++++++++++++++++++-----------
1 files changed, 28 insertions(+), 11 deletions(-)
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 6286bdc..4aa3cb6 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -64,9 +64,14 @@ static struct hv_util_service util_shutdown = {
.util_cb = shutdown_onchannelcallback,
};
+static int hv_timesync_init(struct hv_util_service *srv);
+static void hv_timesync_deinit(void);
+
static void timesync_onchannelcallback(void *context);
static struct hv_util_service util_timesynch = {
.util_cb = timesync_onchannelcallback,
+ .util_init = hv_timesync_init,
+ .util_deinit = hv_timesync_deinit,
};
static void heartbeat_onchannelcallback(void *context);
@@ -201,7 +206,6 @@ static void hv_set_host_time(struct work_struct *work)
host_ts = ns_to_timespec(host_tns);
do_settimeofday(&host_ts);
- kfree(wrk);
}
/*
@@ -217,22 +221,24 @@ static void hv_set_host_time(struct work_struct *work)
* typically used as a hint to the guest. The guest is under no obligation
* to discipline the clock.
*/
+static struct adj_time_work wrk;
static inline void adj_guesttime(u64 hosttime, u64 reftime, u8 flags)
{
- struct adj_time_work *wrk;
- wrk = kmalloc(sizeof(struct adj_time_work), GFP_ATOMIC);
- if (wrk == NULL)
+ /*
+ * This check is safe since we are executing in the
+ * interrupt context and time synch messages arre always
+ * delivered on the same CPU.
+ */
+ if (work_pending(&wrk.work))
return;
- wrk->host_time = hosttime;
- wrk->ref_time = reftime;
- wrk->flags = flags;
+ wrk.host_time = hosttime;
+ wrk.ref_time = reftime;
+ wrk.flags = flags;
if ((flags & (ICTIMESYNCFLAG_SYNC | ICTIMESYNCFLAG_SAMPLE)) != 0) {
- INIT_WORK(&wrk->work, hv_set_host_time);
- schedule_work(&wrk->work);
- } else
- kfree(wrk);
+ schedule_work(&wrk.work);
+ }
}
/*
@@ -457,6 +463,17 @@ static struct hv_driver util_drv = {
.remove = util_remove,
};
+static int hv_timesync_init(struct hv_util_service *srv)
+{
+ INIT_WORK(&wrk.work, hv_set_host_time);
+ return 0;
+}
+
+static void hv_timesync_deinit(void)
+{
+ cancel_work_sync(&wrk.work);
+}
+
static int __init init_hyperv_utils(void)
{
pr_info("Registering HyperV Utility Driver\n");
--
1.7.4.1
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