Re: [PATCH] bnx2fc:Add proper locking protection in bnx2fc_ctrlr_enabled

From: Chad Dupuis
Date: Tue Dec 15 2015 - 11:43:06 EST

On Sat, 12 Dec 2015, Nicholas Krause wrote:

This adds proper locking protection in bnx2fc_ctrl_enabled around
the calls to the functions, _bnx2fc_enable and _bnx2fc_disable in
order to avoid concurrent access on these functions accessing global
referenced data structures in their internal intended work.

Signed-off-by: Nicholas Krause <xerofoify@xxxxxxxxx>
drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index 67405c6..e43648f 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -2177,13 +2177,21 @@ static int bnx2fc_ctlr_enabled(struct fcoe_ctlr_device *cdev)
struct fcoe_ctlr *ctlr = fcoe_ctlr_device_priv(cdev);

+ rtnl_lock();
+ mutex_lock(&bnx2fc_dev_lock);
switch (cdev->enabled) {
+ rtnl_unlock();
+ mutex_unlock(&bnx2fc_dev_lock);
return __bnx2fc_enable(ctlr);
+ rtnl_unlock();
+ mutex_unlock(&bnx2fc_dev_lock);
return __bnx2fc_disable(ctlr);
+ rtnl_unlock();
+ mutex_unlock(&bnx2fc_dev_lock);
return -ENOTSUPP;

Nack. All we end up protecting is the check of cdev->enabled and I do not believe taking two mutexes is required for that.
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