[PATCH 4.9 46/77] scsi: storvsc: fix memory leak on ring buffer busy

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Long Li <longli@xxxxxxxxxxxxx>

commit 0208eeaa650c5c866a3242201678a19e6dc4a14e upstream.

When storvsc is sending I/O to Hyper-v, it may allocate a bigger buffer
descriptor for large data payload that can't fit into a pre-allocated
buffer descriptor. This bigger buffer is freed on return path.

If I/O request to Hyper-v fails due to ring buffer busy, the storvsc
allocated buffer descriptor should also be freed.

[mkp: applied by hand]

Fixes: be0cf6ca301c ("scsi: storvsc: Set the tablesize based on the information given by the host")
Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/scsi/storvsc_drv.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1559,6 +1559,8 @@ static int storvsc_queuecommand(struct S
 	ret = storvsc_do_io(dev, cmd_request);
 
 	if (ret == -EAGAIN) {
+		if (payload_sz > sizeof(cmd_request->mpb))
+			kfree(payload);
 		/* no more space */
 		return SCSI_MLQUEUE_DEVICE_BUSY;
 	}