[PATCH v6 10/11] vhost-scsi: flush IO vqs then send TMF rsp

[Mike Christie <michael.christie@oracle.com>]

With one worker we will always send the scsi cmd responses then send the
TMF rsp, because LIO will always complete the scsi cmds first then call
into us to send the TMF response.

With multiple workers, the IO vq workers could be running while the
TMF/ctl vq worker is so this has us do a flush before completing the TMF
to make sure cmds are completed when it's work is later queued and run.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/vhost/scsi.c  | 22 +++++++++++++++++++---
 drivers/vhost/vhost.c |  6 ++++++
 drivers/vhost/vhost.h |  1 +
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 3e86b5fbeca6..48dba4fe2dac 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1158,12 +1158,28 @@ static void vhost_scsi_tmf_resp_work(struct vhost_work *work)
 {
 	struct vhost_scsi_tmf *tmf = container_of(work, struct vhost_scsi_tmf,
 						  vwork);
-	int resp_code;
+	struct vhost_virtqueue *ctl_vq, *vq;
+	int resp_code, i;
+
+	if (tmf->scsi_resp == TMR_FUNCTION_COMPLETE) {
+		/*
+		 * Flush IO vqs that don't share a worker with the ctl to make
+		 * sure they have sent their responses before us.
+		 */
+		ctl_vq = &tmf->vhost->vqs[VHOST_SCSI_VQ_CTL].vq;
+		for (i = VHOST_SCSI_VQ_IO; i < tmf->vhost->dev.nvqs; i++) {
+			vq = &tmf->vhost->vqs[i].vq;
+
+			if (vhost_vq_is_setup(vq) &&
+			    vq->worker != ctl_vq->worker) {
+				vhost_vq_flush(vq);
+			}
+		}
 
-	if (tmf->scsi_resp == TMR_FUNCTION_COMPLETE)
 		resp_code = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
-	else
+	} else {
 		resp_code = VIRTIO_SCSI_S_FUNCTION_REJECTED;
+	}
 
 	vhost_scsi_send_tmf_resp(tmf->vhost, &tmf->svq->vq, tmf->in_iovs,
 				 tmf->vq_desc, &tmf->resp_iov, resp_code);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index f812daf25648..1fa5e9a49092 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -275,6 +275,12 @@ void vhost_dev_flush(struct vhost_dev *dev)
 }
 EXPORT_SYMBOL_GPL(vhost_dev_flush);
 
+void vhost_vq_flush(struct vhost_virtqueue *vq)
+{
+	vhost_work_flush_on(vq->worker);
+}
+EXPORT_SYMBOL_GPL(vhost_vq_flush);
+
 /* A lockless hint for busy polling code to exit the loop */
 bool vhost_vq_has_work(struct vhost_virtqueue *vq)
 {
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index ef55fae2517c..395707c680e5 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -53,6 +53,7 @@ int vhost_poll_start(struct vhost_poll *poll, struct file *file);
 void vhost_poll_stop(struct vhost_poll *poll);
 void vhost_poll_queue(struct vhost_poll *poll);
 void vhost_dev_flush(struct vhost_dev *dev);
+void vhost_vq_flush(struct vhost_virtqueue *vq);
 
 struct vhost_log {
 	u64 addr;
-- 
2.25.1

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