[PATCH 02/11] scsi: add scsi_host_flush_commands() helper

[Hannes Reinecke <hare@suse.de>]

Add a helper scsi_host_flush_commands() to terminate all outstanding
commands on a scsi host.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/hosts.c     | 29 +++++++++++++++++++++++++++++
 include/scsi/scsi_host.h |  1 +
 2 files changed, 30 insertions(+)

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 1d669e47b692..c26fa1fe6103 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -650,3 +650,32 @@ void scsi_flush_work(struct Scsi_Host *shost)
 	flush_workqueue(shost->work_q);
 }
 EXPORT_SYMBOL_GPL(scsi_flush_work);
+
+static bool flush_cmds_iter(struct request *rq, void *data, bool reserved)
+{
+	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
+	int status = *(int *)data;
+
+	if (reserved)
+		return true;
+	scsi_dma_unmap(scmd);
+	scmd->result = status << 16;
+	scmd->scsi_done(scmd);
+	return true;
+}
+
+/**
+ * scsi_host_flush_commands -- Terminate all running commands
+ * @shost:	Scsi Host on which commands should be terminated
+ * @status:	Status to be set for the terminated commands
+ *
+ * There is no protection against modification of the number
+ * of outstanding commands. It is the responsibility of the
+ * caller to ensure that concurrent I/O submission and/or
+ * completion is stopped when calling this function.
+ */
+void scsi_host_flush_commands(struct Scsi_Host *shost, int status)
+{
+	blk_mq_tagset_busy_iter(&shost->tag_set, flush_cmds_iter, &status);
+}
+EXPORT_SYMBOL_GPL(scsi_host_flush_commands);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index f577647bf5f2..cb9a6fe9ad5b 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -735,6 +735,7 @@ extern int scsi_host_busy(struct Scsi_Host *shost);
 extern void scsi_host_put(struct Scsi_Host *t);
 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
 extern const char *scsi_host_state_name(enum scsi_host_state);
+extern void scsi_host_flush_commands(struct Scsi_Host *shost, int status);
 
 static inline int __must_check scsi_add_host(struct Scsi_Host *host,
 					     struct device *dev)
-- 
2.16.4