[PATCH] nvme-fc: fix reference leak in nvme_fc_nvme_discovery_store()

[Martin George]

nvme_fc_nvme_discovery_store() takes an lport and rport reference before
checking whether the rport is already queued on the local discovery
list. On the retry path (goto restart), rports that were queued in an
earlier pass are skipped by the list_empty() check, but the references
taken for them in the current pass are never dropped, leaking one lport
and one rport reference per retry.

Check list_empty() first and only take references for rports that are
actually added to the local discovery list.

Signed-off-by: Martin George <marting at netapp.com>
---
 drivers/nvme/host/fc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 48454cb7a0fc..03f6fffc9574 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -3778,6 +3778,9 @@ static ssize_t nvme_fc_nvme_discovery_store(struct device *dev,
 restart:
 	list_for_each_entry(lport, &nvme_fc_lport_list, port_list) {
 		list_for_each_entry(rport, &lport->endp_list, endp_list) {
+			/* skip rports already queued for discovery */
+			if (!list_empty(&rport->disc_list))
+				continue;
 			if (!nvme_fc_lport_get(lport))
 				continue;
 			if (!nvme_fc_rport_get(rport)) {
@@ -3799,9 +3802,7 @@ static ssize_t nvme_fc_nvme_discovery_store(struct device *dev,
 				       "failures\n");
 				goto process_local_list;
 			}
-			if (list_empty(&rport->disc_list))
-				list_add_tail(&rport->disc_list,
-					      &local_disc_list);
+			list_add_tail(&rport->disc_list, &local_disc_list);
 		}
 	}
 
-- 
2.43.0