[PATCH v3 06/17] scsi-multipath: clear path when device is blocked

[John Garry]

Add scsi_mpath_dev_clear_path() to clear a device path when it becomes
blocked, and call from __scsi_internal_device_block_nowait().

Signed-off-by: John Garry <john.g.garry at oracle.com>
---
 drivers/scsi/scsi_lib.c       |  3 +++
 drivers/scsi/scsi_multipath.c | 11 +++++++++++
 include/scsi/scsi_multipath.h |  5 +++++
 3 files changed, 19 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 22e2e3223440d..cc34253c467a2 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -34,6 +34,7 @@
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_transport.h> /* scsi_init_limits() */
+#include <scsi/scsi_multipath.h>
 #include <scsi/scsi_dh.h>
 
 #include <trace/events/scsi.h>
@@ -2931,6 +2932,8 @@ EXPORT_SYMBOL(scsi_target_resume);
 
 static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
 {
+	if (sdev->scsi_mpath_dev)
+		scsi_mpath_dev_clear_path(sdev->scsi_mpath_dev);
 	if (scsi_device_set_state(sdev, SDEV_BLOCK))
 		return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
 
diff --git a/drivers/scsi/scsi_multipath.c b/drivers/scsi/scsi_multipath.c
index ca4ab720c19af..0f3f3f9fa5fae 100644
--- a/drivers/scsi/scsi_multipath.c
+++ b/drivers/scsi/scsi_multipath.c
@@ -113,6 +113,17 @@ static ssize_t scsi_mpath_device_vpd_id_show(struct device *dev,
 }
 static DEVICE_ATTR(vpd_id, S_IRUGO, scsi_mpath_device_vpd_id_show, NULL);
 
+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);
+}
+EXPORT_SYMBOL_GPL(scsi_mpath_dev_clear_path);
+
 static ssize_t scsi_mpath_device_iopolicy_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
diff --git a/include/scsi/scsi_multipath.h b/include/scsi/scsi_multipath.h
index 5cc37acaa664f..d8644d6261992 100644
--- a/include/scsi/scsi_multipath.h
+++ b/include/scsi/scsi_multipath.h
@@ -49,6 +49,7 @@ int scsi_mpath_dev_alloc(struct scsi_device *sdev);
 void scsi_mpath_dev_release(struct scsi_device *sdev);
 int scsi_multipath_init(void);
 void scsi_multipath_exit(void);
+void scsi_mpath_dev_clear_path(struct scsi_mpath_device *scsi_mpath_dev);
 void scsi_mpath_remove_device(struct scsi_mpath_device *scsi_mpath_dev);
 void scsi_mpath_add_sysfs_link(struct scsi_device *sdev);
 void scsi_mpath_remove_sysfs_link(struct scsi_device *sdev);
@@ -80,6 +81,10 @@ void scsi_mpath_remove_device(struct scsi_mpath_device *scsi_mpath_dev)
 {
 }
 static inline
+void scsi_mpath_dev_clear_path(struct scsi_mpath_device *scsi_mpath_dev)
+{
+}
+static inline
 int scsi_mpath_get_head(struct scsi_mpath_head *scsi_mpath_head)
 {
 	return 0;
-- 
2.43.7