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Message-ID: <Pine.LNX.4.64.0907181722060.26792@ask.diku.dk>
Date: Sat, 18 Jul 2009 17:22:41 +0200 (CEST)
From: Julia Lawall <julia@...u.dk>
To: James.Bottomley@...senPartnership.com, linux-scsi@...r.kernel.org,
linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH] drivers/scsi: possible double spin_lock_irqsave
From: Julia Lawall <julia@...u.dk>
If both the test on rport and the call to get_device fail, then the lock is
already held. The re-lock is thus moved up into the two branches.
On the other hand if kref_put should not be called with the lock held then
something else should be done.
The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@@
expression lock1,lock2;
expression flags;
@@
*spin_lock_irqsave(lock1,flags)
... when != flags
*spin_lock_irqsave(lock2,flags)
// </smpl>
Signed-off-by: Julia Lawall <julia@...u.dk>
---
drivers/scsi/ibmvscsi/ibmvfc.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 166d964..d2b88bd 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -4278,15 +4278,16 @@ static void ibmvfc_rport_add_thread(struct work_struct *work)
if (!rport) {
spin_unlock_irqrestore(vhost->host->host_lock, flags);
ibmvfc_tgt_add_rport(tgt);
+ spin_lock_irqsave(vhost->host->host_lock, flags);
} else if (get_device(&rport->dev)) {
spin_unlock_irqrestore(vhost->host->host_lock, flags);
tgt_dbg(tgt, "Setting rport roles\n");
fc_remote_port_rolechg(rport, tgt->ids.roles);
put_device(&rport->dev);
+ spin_lock_irqsave(vhost->host->host_lock, flags);
}
kref_put(&tgt->kref, ibmvfc_release_tgt);
- spin_lock_irqsave(vhost->host->host_lock, flags);
break;
}
}
--
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