[PATCH] fix two problems in tmf

[Hu Tao]

This patch fix two problems in tmf:

  1. race in virtscsi_tmf that the cmd may have been already freed
     when waking up from the completion

  2. cmd leak if virtscsi_kick_cmd fails.


Signed-off-by: Hu Tao <hutao@xxxxxxxxxxxxxx>
---
 drivers/scsi/virtio_scsi.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index efccd72..3b8a6e6 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -175,7 +175,8 @@ static void virtscsi_complete_free(void *buf)
 
 	if (cmd->comp)
 		complete_all(cmd->comp);
-	mempool_free(cmd, virtscsi_cmd_pool);
+	else
+		mempool_free(cmd, virtscsi_cmd_pool);
 }
 
 static void virtscsi_ctrl_done(struct virtqueue *vq)
@@ -311,21 +312,23 @@ out:
 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 {
 	DECLARE_COMPLETION_ONSTACK(comp);
-	int ret;
+	int ret = FAILED;
 
 	cmd->comp = &comp;
 	ret = virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd,
 			       sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
 			       GFP_NOIO);
 	if (ret < 0)
-		return FAILED;
+		goto failed;
 
 	wait_for_completion(&comp);
-	if (cmd->resp.tmf.response != VIRTIO_SCSI_S_OK &&
-	    cmd->resp.tmf.response != VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
-		return FAILED;
+	if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
+	    cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
+		ret = SUCCESS;
 
-	return SUCCESS;
+failed:
+	mempool_free(cmd, virtscsi_cmd_pool);
+	return ret;
 }
 
 static int virtscsi_device_reset(struct scsi_cmnd *sc)
-- 
1.7.1


--pWyiEgJYm5f9v55/--
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