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[1/5] vhost-scsi: Hold tv_tpg_mutex when decrementing tv_tpg_vhost_count

Message ID 20230223001949.2884-2-michael.christie@oracle.com (mailing list archive)
State Not Applicable
Headers show
Series vhost-scsi: Fix management operation hangs | expand

Commit Message

Mike Christie Feb. 23, 2023, 12:19 a.m. UTC 
This has us hold the tv_tpg_mutex when decrementing the
tv_tpg_vhost_count in vhost_scsi_set_endpoint's failure path. We
currently don't need to because we are holding the vhost_scsi_mutex and
the dev.mutex when incrementing/decrementing in the normal paths, and we
can't hit the tv_tpg_port_count check in vhost_scsi_drop_nexus during
this time because there is a nexus and we have a refcount to the tpg.

In the next patch we will change when we hold the vhost_scsi_mutex, so it's
not always held in set/clear endpoint and in the future we might change
the dev.mutex use, so this future proofs us.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/vhost/scsi.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index d5ecb8876fc9..c31659aa5466 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1658,7 +1658,9 @@  vhost_scsi_set_endpoint(struct vhost_scsi *vs,
 	for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) {
 		tpg = vs_tpg[i];
 		if (tpg) {
+			mutex_lock(&tpg->tv_tpg_mutex);
 			tpg->tv_tpg_vhost_count--;
+			mutex_unlock(&tpg->tv_tpg_mutex);
 			target_undepend_item(&tpg->se_tpg.tpg_group.cg_item);
 		}
 	}