Commit b46b4a8a authored Aug 21, 2020 by Vineeth Pillai Committed by Wei Liu Aug 24, 2020

hv_utils: drain the timesync packets on onchannelcallback



There could be instances where a system stall prevents the timesync
packets to be consumed. And this might lead to more than one packet
pending in the ring buffer. Current code empties one packet per callback
and it might be a stale one. So drain all the packets from ring buffer
on each callback.

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200821152849.99517-1-viremana@linux.microsoft.com


Signed-off-by: Wei Liu <wei.liu@kernel.org>

parent 90b125f4

drivers/hv/hv_util.c

+16 −3

Original line number	Diff line number	Diff line
		@@ -387,10 +387,23 @@ static void timesync_onchannelcallback(void *context)
		struct ictimesync_ref_data *refdata;
		u8 *time_txf_buf = util_timesynch.recv_buffer;

		vmbus_recvpacket(channel, time_txf_buf,
		HV_HYP_PAGE_SIZE, &recvlen, &requestid);
		/*
		* Drain the ring buffer and use the last packet to update
		* host_ts
		*/
		while (1) {
		int ret = vmbus_recvpacket(channel, time_txf_buf,
		HV_HYP_PAGE_SIZE, &recvlen,
		&requestid);
		if (ret) {
		pr_warn_once("TimeSync IC pkt recv failed (Err: %d)\n",
		ret);
		break;
		}

		if (!recvlen)
		break;

		if (recvlen > 0) {
		icmsghdrp = (struct icmsg_hdr *)&time_txf_buf[
		sizeof(struct vmbuspipe_hdr)];

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