Patch "scsi: ibmvfc: Avoid path failures during live migration" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    scsi: ibmvfc: Avoid path failures during live migration

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-ibmvfc-avoid-path-failures-during-live-migratio.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 898bf0c21fcfc8e9f957a43f1875e4efb2c6a1bc
Author: Brian King <brking@xxxxxxxxxxxxxxxxxx>
Date:   Wed Oct 26 13:13:56 2022 -0500

    scsi: ibmvfc: Avoid path failures during live migration
    
    [ Upstream commit 62fa3ce05d5d73c5eccc40b2db493f55fecfc446 ]
    
    Fix an issue reported when performing a live migration when multipath is
    configured with a short fast fail timeout of 5 seconds and also to have
    no_path_retry set to fail. In this scenario, all paths would go into the
    devloss state while the ibmvfc driver went through discovery to log back
    in. On a loaded system, the discovery might take longer than 5 seconds,
    which was resulting in all paths being marked failed, which then resulted
    in a read only filesystem.
    
    This patch changes the migration code in ibmvfc to avoid deleting rports at
    all in this scenario, so we avoid losing all paths.
    
    Signed-off-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20221026181356.148517-1-brking@xxxxxxxxxxxxxxxxxx
    Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index f6d6539c657f..b793e342ab7c 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -635,8 +635,13 @@ static void ibmvfc_init_host(struct ibmvfc_host *vhost)
 		memset(vhost->async_crq.msgs, 0, PAGE_SIZE);
 		vhost->async_crq.cur = 0;
 
-		list_for_each_entry(tgt, &vhost->targets, queue)
-			ibmvfc_del_tgt(tgt);
+		list_for_each_entry(tgt, &vhost->targets, queue) {
+			if (vhost->client_migrated)
+				tgt->need_login = 1;
+			else
+				ibmvfc_del_tgt(tgt);
+		}
+
 		scsi_block_requests(vhost->host);
 		ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_INIT);
 		vhost->job_step = ibmvfc_npiv_login;
@@ -2822,9 +2827,12 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost)
 			/* We need to re-setup the interpartition connection */
 			dev_info(vhost->dev, "Partition migrated, Re-enabling adapter\n");
 			vhost->client_migrated = 1;
+
+			scsi_block_requests(vhost->host);
 			ibmvfc_purge_requests(vhost, DID_REQUEUE);
-			ibmvfc_link_down(vhost, IBMVFC_LINK_DOWN);
+			ibmvfc_set_host_state(vhost, IBMVFC_LINK_DOWN);
 			ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_REENABLE);
+			wake_up(&vhost->work_wait_q);
 		} else if (crq->format == IBMVFC_PARTNER_FAILED || crq->format == IBMVFC_PARTNER_DEREGISTER) {
 			dev_err(vhost->dev, "Host partner adapter deregistered or failed (rc=%d)\n", crq->format);
 			ibmvfc_purge_requests(vhost, DID_ERROR);