[PATCH 1/1] UBUNTU: SAUCE: hv_storvsc: Account for in-transit packets in the RESET path

[Andy Whitcroft]

From: "K. Y. Srinivasan" <kys at microsoft.com>

Properly account for I/O in transit before returning from the RESET call.
In the absense of this patch we could have a situation where the host may
respond to a command that was issued prior to the issuance of the RESET
command at some arbitrary time after responding to the RESET command.
Currently, the host does not do anything with the RESET command and so
it is ok to wait for the in-transit I/O to be accounted for. If the host
side sematics changes, we will have to revisit this.

Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>

BugLink: http://bugs.launchpad.net/bugs/978394
Signed-off-by: Andy Whitcroft <apw at canonical.com>
---
 drivers/scsi/storvsc_drv.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 5848a97..af3383f 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1223,7 +1223,12 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
 	/*
 	 * At this point, all outstanding requests in the adapter
 	 * should have been flushed out and return to us
+	 * There is a potential race here where the host may be in
+	 * the process of responding when we return from here.
+	 * Just wait for all in-transit packets to be accounted for
+	 * before we return from here.
 	 */
+	storvsc_wait_to_drain(stor_device);
 
 	return SUCCESS;
 }
-- 
1.7.9.5