[PATCH 1/4] drivers/scsi/qla2xxx/qla_init.c: convert nested spin_lock_irqsave to spin_lock

[Madhu Iyengar]

Julia,

We've submitted this patch upstream to scsi-misc already on Oct 15th (Dan Carpenter had flagged this). Here's the submission info (patch (01/12) or item #12 in the link below:

http://marc.info/?l=linux-scsi&w=2&r=1&s=qla2xxx&q=b

Thanks,
Madhu

-----Original Message-----
From: linux-scsi-owner at vger.kernel.org [mailto:linux-scsi-owner at vger.kernel.org] On Behalf Of Julia Lawall
Sent: Tuesday, October 19, 2010 2:44 AM
To: Andrew Vasquez
Cc: kernel-janitors at vger.kernel.org; Linux Driver; James E.J. Bottomley; Grant Likely; linux-scsi at vger.kernel.org; linux-kernel at vger.kernel.org; devicetree-discuss at lists.ozlabs.org
Subject: [PATCH 1/4] drivers/scsi/qla2xxx/qla_init.c: convert nested spin_lock_irqsave to spin_lock

From: Julia Lawall <julia at diku.dk>

If spin_lock_irqsave is called twice in a row with the same second
argument, the interrupt state at the point of the second call overwrites
the value saved by the first call.  Indeed, the second call does not need
to save the interrupt state, so it is changed to a simple spin_lock.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <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 at diku.dk>

---
 drivers/scsi/qla2xxx/qla_init.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
index 3cafbef..c8d0b12 100644
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -1818,14 +1818,14 @@ qla2x00_init_rings(scsi_qla_host_t *vha)
 		qla2x00_init_response_q_entries(rsp);
 	}
 
-	spin_lock_irqsave(&ha->vport_slock, flags);
+	spin_lock(&ha->vport_slock);
 	/* Clear RSCN queue. */
 	list_for_each_entry(vp, &ha->vp_list, list) {
 		vp->rscn_in_ptr = 0;
 		vp->rscn_out_ptr = 0;
 	}
 
-	spin_unlock_irqrestore(&ha->vport_slock, flags);
+	spin_unlock(&ha->vport_slock);
 
 	ha->isp_ops->config_rings(vha);
 

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