linux-kernel - [PATCH 4.19 112/149] Revert "scsi: libfc: Add WARN

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Date:   Tue, 12 Mar 2019 10:08:50 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ross Lagerwall <ross.lagerwall@...rix.com>,
        Hannes Reinecke <hare@...e.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 112/149] Revert "scsi: libfc: Add WARN_ON() when deleting rports"

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit d8f6382a7d026989029e2e50c515df954488459b ]

This reverts commit bbc0f8bd88abefb0f27998f40a073634a3a2db89.

It added a warning whose intent was to check whether the rport was still
linked into the peer list. It doesn't work as intended and gives false
positive warnings for two reasons:

1) If the rport is never linked into the peer list it will not be
considered empty since the list_head is never initialized.

2) If the rport is deleted from the peer list using list_del_rcu(), then
the list_head is in an undefined state and it is not considered empty.

Signed-off-by: Ross Lagerwall <ross.lagerwall@...rix.com>
Reviewed-by: Hannes Reinecke <hare@...e.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/scsi/libfc/fc_rport.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index 372387a450df..1797e47fab38 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -184,7 +184,6 @@ void fc_rport_destroy(struct kref *kref)
 	struct fc_rport_priv *rdata;

 	rdata = container_of(kref, struct fc_rport_priv, kref);
-	WARN_ON(!list_empty(&rdata->peers));
 	kfree_rcu(rdata, rcu);
 }
 EXPORT_SYMBOL(fc_rport_destroy);
-- 
2.19.1