Drivers: hv: vmbus: Fix a Host signaling bug

Currently we have two policies for deciding when to signal the host:
One based on the ring buffer state and the other based on what the
VMBUS client driver wants to do. Consider the case when the client
wants to explicitly control when to signal the host. In this case,
if the client were to defer signaling, we will not be able to signal
the host subsequently when the client does want to signal since the
ring buffer state will prevent the signaling. Implement logic to
have only one signaling policy in force for a given channel.

Signed-off-by: K. Y. Srinivasan <[email protected]>
Reviewed-by: Haiyang Zhang <[email protected]>
Tested-by: Haiyang Zhang <[email protected]>
Cc: <[email protected]> # v4.2+
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
K. Y. Srinivasan 2015-12-14 16:01:54 -08:00 • committed by Greg Kroah-Hartman
commit 8599846d73
2 changed files with 36 additions and 0 deletions

View file

@ -653,10 +653,19 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
* on the ring. We will not signal if more data is
* to be placed.
*
* Based on the channel signal state, we will decide
* which signaling policy will be applied.
*
* If we cannot write to the ring-buffer; signal the host
* even if we may not have written anything. This is a rare
* enough condition that it should not matter.
*/
if (channel->signal_policy)
signal = true;
else
kick_q = true;
if (((ret == 0) && kick_q && signal) || (ret))
vmbus_setevent(channel);
@ -756,10 +765,19 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
* on the ring. We will not signal if more data is
* to be placed.
*
* Based on the channel signal state, we will decide
* which signaling policy will be applied.
*
* If we cannot write to the ring-buffer; signal the host
* even if we may not have written anything. This is a rare
* enough condition that it should not matter.
*/
if (channel->signal_policy)
signal = true;
else
kick_q = true;
if (((ret == 0) && kick_q && signal) || (ret))
vmbus_setevent(channel);