ACK: [SRU][Precise][PATCH 1/1] hv: do not lose pending heartbeat vmbus packets

[Stefan Bader]

On 10.11.2016 21:51, Joseph Salisbury wrote:
> From: Long Li <longli at microsoft.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1632786
> 
> The host keeps sending heartbeat packets independent of the
> guest responding to them.  Even though we respond to the heartbeat messages at
> interrupt level, we can have situations where there maybe multiple heartbeat
> messages pending that have not been responded to. For instance this occurs when the
> VM is paused and the host continues to send the heartbeat messages.
> Address this issue by draining and responding to all
> the heartbeat messages that maybe pending.
> 
> Signed-off-by: Long Li <longli at microsoft.com>
> Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
> CC: Stable <stable at vger.kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> (cherry picked from commit 407a3aee6ee2d2cb46d9ba3fc380bc29f35d020c)
> Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
> ---
>  drivers/hv/hv_util.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
> index dbb8b8e..79c9789 100644
> --- a/drivers/hv/hv_util.c
> +++ b/drivers/hv/hv_util.c
> @@ -226,10 +226,14 @@ static void heartbeat_onchannelcallback(void *context)
>  	struct heartbeat_msg_data *heartbeat_msg;
>  	u8 *hbeat_txf_buf = util_heartbeat.recv_buffer;
>  
> -	vmbus_recvpacket(channel, hbeat_txf_buf,
> -			 PAGE_SIZE, &recvlen, &requestid);
> +	while (1) {
> +
> +		vmbus_recvpacket(channel, hbeat_txf_buf,
> +				 PAGE_SIZE, &recvlen, &requestid);
> +
> +		if (!recvlen)
> +			break;
>  
> -	if (recvlen > 0) {
>  		icmsghdrp = (struct icmsg_hdr *)&hbeat_txf_buf[
>  				sizeof(struct vmbuspipe_hdr)];
>  
> 


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