[dm-devel] [PATCH 1/2] dm-mpath: Enable hw_handler_params to take effect if hw_handler is the same between new and old

[tang.junhui at zte.com.cn]

From: "tang.junhui" <tang.junhui at zte.com.cn>

If the hardware handle which a device has already attached is the same
with m->hw_handler_name, m->hw_handler_params should not be ignored, but
be enabled to take effect.

Signed-off-by: tang.junhui <tang.junhui at zte.com.cn>
---
 drivers/md/dm-mpath.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 0caab4b..b1aba63 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -849,19 +849,23 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
 retain:
 		attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
 		if (attached_handler_name) {
+			/* clear any hw_handler_params associated with
+			 * m->hw_handler_params if a different handler has
+			 * already been attached.
+			 */
+			if(!m->hw_handler_name || strcmp(attached_handler_name, m->hw_handler_name))
+			{
+				kfree(m->hw_handler_params);
+				m->hw_handler_params = NULL;
+			}
 			/*
 			 * Reset hw_handler_name to match the attached handler
-			 * and clear any hw_handler_params associated with the
-			 * ignored handler.
 			 *
 			 * NB. This modifies the table line to show the actual
 			 * handler instead of the original table passed in.
 			 */
 			kfree(m->hw_handler_name);
 			m->hw_handler_name = attached_handler_name;
-
-			kfree(m->hw_handler_params);
-			m->hw_handler_params = NULL;
 		}
 	}
 
-- 
2.8.1.windows.1