[PATCH v4 17/28] scsi-multipath: clear path when device is blocked

[John Garry]

From: John Garry <john.garry@xxxxxxxxx>

Add scsi_mpath_dev_clear_path() to clear a device path when it becomes
blocked.

Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
 drivers/scsi/scsi_lib.c       |  6 +++++-
 drivers/scsi/scsi_multipath.c | 10 ++++++++++
 include/scsi/scsi_multipath.h |  5 +++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 22e2e3223440d..dafa781288046 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -35,6 +35,7 @@
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_transport.h> /* scsi_init_limits() */
 #include <scsi/scsi_dh.h>
+#include <scsi/scsi_multipath.h>
 
 #include <trace/events/scsi.h>
 
@@ -3007,13 +3008,16 @@ static void scsi_device_block(struct scsi_device *sdev, void *data)
 	mutex_lock(&sdev->state_mutex);
 	err = __scsi_internal_device_block_nowait(sdev);
 	state = sdev->sdev_state;
-	if (err == 0)
+	if (err == 0) {
 		/*
 		 * scsi_stop_queue() must be called with the state_mutex
 		 * held. Otherwise a simultaneous scsi_start_queue() call
 		 * might unquiesce the queue before we quiesce it.
 		 */
 		scsi_stop_queue(sdev);
+		if (sdev->scsi_mpath_dev)
+			scsi_mpath_dev_clear_path(sdev->scsi_mpath_dev);
+	}
 
 	mutex_unlock(&sdev->state_mutex);
 
diff --git a/drivers/scsi/scsi_multipath.c b/drivers/scsi/scsi_multipath.c
index 9a4b35c597778..6a2b06c148c1a 100644
--- a/drivers/scsi/scsi_multipath.c
+++ b/drivers/scsi/scsi_multipath.c
@@ -230,6 +230,16 @@ static int scsi_multipath_sdev_init(struct scsi_device *sdev)
 	return 0;
 }
 
+void scsi_mpath_dev_clear_path(struct scsi_mpath_device *scsi_mpath_dev)
+{
+       struct mpath_device *mpath_device = &scsi_mpath_dev->mpath_device;
+       struct scsi_mpath_head *scsi_mpath_head = scsi_mpath_dev->scsi_mpath_head;
+       struct mpath_head *mpath_head = &scsi_mpath_head->mpath_head;
+
+       if (mpath_clear_current_path(mpath_device))
+               mpath_synchronize(mpath_head);
+}
+
 static void scsi_mpath_clone_end_io(struct bio *clone)
 {
 	struct bio *master_bio = clone->bi_private;
diff --git a/include/scsi/scsi_multipath.h b/include/scsi/scsi_multipath.h
index 5cc37acaa664f..8f58c44d96a77 100644
--- a/include/scsi/scsi_multipath.h
+++ b/include/scsi/scsi_multipath.h
@@ -54,6 +54,7 @@ void scsi_mpath_add_sysfs_link(struct scsi_device *sdev);
 void scsi_mpath_remove_sysfs_link(struct scsi_device *sdev);
 int scsi_mpath_get_head(struct scsi_mpath_head *scsi_mpath_head);
 void scsi_mpath_put_head(struct scsi_mpath_head *scsi_mpath_head);
+void scsi_mpath_dev_clear_path(struct scsi_mpath_device *scsi_mpath_dev);
 #else /* CONFIG_SCSI_MULTIPATH */
 
 struct scsi_mpath_head {
@@ -88,6 +89,10 @@ static inline
 void scsi_mpath_put_head(struct scsi_mpath_head *scsi_mpath_head)
 {
 }
+static inline
+void scsi_mpath_dev_clear_path(struct scsi_mpath_device *scsi_mpath_dev)
+{
+}
 static inline void scsi_mpath_add_sysfs_link(struct scsi_device *sdev)
 {
 }
-- 
2.43.7