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Drivers: hv: vmbus: Fix a siganlling host signalling issue

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Handle the case when the write to the ringbuffer fails. In this case,
unconditionally signal the host. Since we may have deferred signalling
the host based on the kick_q parameter, signalling the host
unconditionally in this case deals with the issue.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
K. Y. Srinivasan 2015-03-18 12:29:30 -07:00 committed by Greg Kroah-Hartman
parent b3a19b36ad
commit 5f5cc81733
1 changed files with 26 additions and 2 deletions
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28
drivers/hv/channel.c
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@ -611,7 +611,19 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
if ((ret == 0) && kick_q && signal)
/*
* Signalling the host is conditional on many factors:
* 1. The ring state changed from being empty to non-empty.
* This is tracked by the variable "signal".
* 2. The variable kick_q tracks if more data will be placed
* on the ring. We will not signal if more data is
* to be placed.
*
* 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 (((ret == 0) && kick_q && signal) || (ret))
vmbus_setevent(channel);
return ret;
@ -702,7 +714,19 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
if ((ret == 0) && kick_q && signal)
/*
* Signalling the host is conditional on many factors:
* 1. The ring state changed from being empty to non-empty.
* This is tracked by the variable "signal".
* 2. The variable kick_q tracks if more data will be placed
* on the ring. We will not signal if more data is
* to be placed.
*
* 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 (((ret == 0) && kick_q && signal) || (ret))
vmbus_setevent(channel);
return ret;