From 981c2ae9bda563d16106d9dba25f4e7cc6612142 Mon Sep 17 00:00:00 2001
From: Martin Wilck <martin.wilck@suse.com>
Date: Apr 13 2021 20:42:37 +0000
Subject: dm mpath: switch paths in dm_blk_ioctl() code path (bsc#1167574,

bsc#1175995, bsc#1184485).

---

diff --git a/patches.suse/dm-mpath-switch-paths-in-dm_blk_ioctl-code-path.patch b/patches.suse/dm-mpath-switch-paths-in-dm_blk_ioctl-code-path.patch
new file mode 100644
index 0000000..14e487f
--- /dev/null
+++ b/patches.suse/dm-mpath-switch-paths-in-dm_blk_ioctl-code-path.patch
@@ -0,0 +1,41 @@
+From: Martin Wilck <mwilck@suse.com>
+Date: Mon, 20 Apr 2020 22:29:09 +0200
+Subject: dm mpath: switch paths in dm_blk_ioctl() code path
+Patch-mainline: v5.8-rc1
+Git-commit: 2361ae595352dec015d14292f1b539242d8446d6
+References: bsc#1167574, bsc#1175995, bsc#1184485
+
+SCSI LUN passthrough code such as qemu's "scsi-block" device model
+pass every IO to the host via SG_IO ioctls. Currently, dm-multipath
+calls choose_pgpath() only in the block IO code path, not in the ioctl
+code path (unless current_pgpath is NULL). This has the effect that no
+path switching and thus no load balancing is done for SCSI-passthrough
+IO, unless the active path fails.
+
+Fix this by using the same logic in multipath_prepare_ioctl() as in
+multipath_clone_and_map().
+
+Note: The allegedly best path selection algorithm, service-time,
+still wouldn't work perfectly, because the io size of the current
+request is always set to 0. Changing that for the IO passthrough
+case would require the ioctl cmd and arg to be passed to dm's
+prepare_ioctl() method.
+
+Signed-off-by: Martin Wilck <mwilck@suse.com>
+Reviewed-by: Hannes Reinecke <hare@suse.de>
+Signed-off-by: Mike Snitzer <snitzer@redhat.com>
+---
+ drivers/md/dm-mpath.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/md/dm-mpath.c
++++ b/drivers/md/dm-mpath.c
+@@ -1862,7 +1862,7 @@ static int multipath_prepare_ioctl(struc
+ 	int r;
+ 
+ 	current_pgpath = READ_ONCE(m->current_pgpath);
+-	if (!current_pgpath)
++	if (!current_pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags))
+ 		current_pgpath = choose_pgpath(m, 0);
+ 
+ 	if (current_pgpath) {
diff --git a/series.conf b/series.conf
index 5e837ce..713f84b 100644
--- a/series.conf
+++ b/series.conf
@@ -13723,6 +13723,7 @@
 	patches.suse/scsi-qla2xxx-Remove-return-value-from-qla_nvme_ls.patch
 	patches.suse/scsi-lpfc-Fix-lpfc_nodelist-leak-when-processing-uns.patch
 	patches.suse/scsi-mpt3sas-fix-reply-queue-count-in-non-rdpq-mode
+	patches.suse/dm-mpath-switch-paths-in-dm_blk_ioctl-code-path.patch
 	patches.suse/0002-dm-crypt-avoid-truncating-the-logical-block-size.patch
 	patches.suse/ext4-fix-EXT_MAX_EXTENT-INDEX-to-check-for-zeroed-eh.patch
 	patches.suse/ext4-Avoid-freeing-inodes-on-dirty-list.patch