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From:   Daniel Wagner <dwagner@suse.de>
To:     linux-nvme@lists.infradead.org
Cc:     linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        Sagi Grimberg <sagi@grimberg.me>,
        James Smart <james.smart@broadcom.com>,
        Chaitanya Kulkarni <kch@nvidia.com>,
        Martin Belanger <Martin.Belanger@dell.com>,
        Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>,
        Daniel Wagner <dwagner@suse.de>
Subject: [PATCH v3 3/4] nvmet-fc: Do not wait in vain when unloading module
Date:   Tue, 18 Apr 2023 15:01:58 +0200
Message-Id: <20230418130159.11075-4-dwagner@suse.de>
In-Reply-To: <20230418130159.11075-1-dwagner@suse.de>
References: <20230418130159.11075-1-dwagner@suse.de>
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When there is no controller to be deleted the module unload path will
still wait on the nvme_fc_unload_proceed completion. Because this will
will never happen the caller will hang forever.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/fc.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 456ee42a6133..df85cf93742b 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -3933,10 +3933,11 @@ static int __init nvme_fc_init_module(void)
 	return ret;
 }
 
-static void
+static bool
 nvme_fc_delete_controllers(struct nvme_fc_rport *rport)
 {
 	struct nvme_fc_ctrl *ctrl;
+	bool cleanup = false;
 
 	spin_lock(&rport->lock);
 	list_for_each_entry(ctrl, &rport->ctrl_list, ctrl_list) {
@@ -3944,21 +3945,28 @@ nvme_fc_delete_controllers(struct nvme_fc_rport *rport)
 			"NVME-FC{%d}: transport unloading: deleting ctrl\n",
 			ctrl->cnum);
 		nvme_delete_ctrl(&ctrl->ctrl);
+		cleanup = true;
 	}
 	spin_unlock(&rport->lock);
+
+	return cleanup;
 }
 
-static void
+static bool
 nvme_fc_cleanup_for_unload(void)
 {
 	struct nvme_fc_lport *lport;
 	struct nvme_fc_rport *rport;
+	bool cleanup = false;
 
 	list_for_each_entry(lport, &nvme_fc_lport_list, port_list) {
 		list_for_each_entry(rport, &lport->endp_list, endp_list) {
-			nvme_fc_delete_controllers(rport);
+			if (nvme_fc_delete_controllers(rport))
+				cleanup = true;
 		}
 	}
+
+	return cleanup;
 }
 
 static void __exit nvme_fc_exit_module(void)
@@ -3968,10 +3976,8 @@ static void __exit nvme_fc_exit_module(void)
 
 	spin_lock_irqsave(&nvme_fc_lock, flags);
 	nvme_fc_waiting_to_unload = true;
-	if (!list_empty(&nvme_fc_lport_list)) {
-		need_cleanup = true;
-		nvme_fc_cleanup_for_unload();
-	}
+	if (!list_empty(&nvme_fc_lport_list))
+		need_cleanup = nvme_fc_cleanup_for_unload();
 	spin_unlock_irqrestore(&nvme_fc_lock, flags);
 	if (need_cleanup) {
 		pr_info("%s: waiting for ctlr deletes\n", __func__);
-- 
2.40.0