[PATCH v7 16/27] scsi-multipath: clear path when device is blocked

[John Garry <john.g.garry@oracle.com>]

From: John Garry <john.garry@linux.dev>

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

Signed-off-by: John Garry <john.garry@linux.dev>
---
 drivers/scsi/scsi_lib.c       |  3 +++
 drivers/scsi/scsi_multipath.c | 10 ++++++++++
 include/scsi/scsi_multipath.h |  5 +++++
 3 files changed, 18 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index af27fd3df8d46..f02b3a50e20cd 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>
 
@@ -3009,6 +3010,8 @@ static void scsi_device_block(struct scsi_device *sdev, void *data)
 		scsi_stop_queue(sdev);
 
 	mutex_unlock(&sdev->state_mutex);
+	if ((err == 0) && sdev->scsi_mpath_dev)
+		scsi_mpath_dev_clear_path(sdev->scsi_mpath_dev);
 
 	WARN_ONCE(err, "%s: failed to block %s in state %d\n",
 		  __func__, dev_name(&sdev->sdev_gendev), state);
diff --git a/drivers/scsi/scsi_multipath.c b/drivers/scsi/scsi_multipath.c
index 68fe50f62158c..b16fe6a55fa73 100644
--- a/drivers/scsi/scsi_multipath.c
+++ b/drivers/scsi/scsi_multipath.c
@@ -238,6 +238,16 @@ 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 d2ef94ebd29af..2064a3e922748 100644
--- a/include/scsi/scsi_multipath.h
+++ b/include/scsi/scsi_multipath.h
@@ -55,6 +55,7 @@ int scsi_mpath_try_get_head(struct scsi_mpath_head *scsi_mpath_head);
 void scsi_mpath_put_head(struct scsi_mpath_head *scsi_mpath_head);
 void scsi_mpath_add_sysfs_link(struct scsi_device *sdev);
 void scsi_mpath_remove_sysfs_link(struct scsi_device *sdev);
+void scsi_mpath_dev_clear_path(struct scsi_mpath_device *scsi_mpath_dev);
 #else /* CONFIG_SCSI_MULTIPATH */
 
 struct scsi_mpath_head {
@@ -99,5 +100,9 @@ static inline void scsi_mpath_add_sysfs_link(struct scsi_device *sdev)
 static inline void scsi_mpath_remove_sysfs_link(struct scsi_device *sdev)
 {
 }
+static inline
+void scsi_mpath_dev_clear_path(struct scsi_mpath_device *scsi_mpath_dev)
+{
+}
 #endif /* CONFIG_SCSI_MULTIPATH */
 #endif /* _SCSI_SCSI_MULTIPATH_H */
-- 
2.43.7