libata: Fix a potential race condition in ata_scsi_park_show()

Peter Moulder has pointed out that there is a slight chance that a
negative value might be passed to jiffies_to_msecs() in
ata_scsi_park_show(). This is fixed by saving the value of jiffies in a
local variable, thus also reducing code since the volatile variable
jiffies is accessed only once.

Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Tejun Heo <tj.kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Elias Oltmanns 2008-11-03 19:01:08 +09:00 committed by Jeff Garzik
parent 3c324283e6
commit a464189de3

View file

@ -190,7 +190,7 @@ static ssize_t ata_scsi_park_show(struct device *device,
struct ata_port *ap;
struct ata_link *link;
struct ata_device *dev;
unsigned long flags;
unsigned long flags, now;
unsigned int uninitialized_var(msecs);
int rc = 0;
@ -208,10 +208,11 @@ static ssize_t ata_scsi_park_show(struct device *device,
}
link = dev->link;
now = jiffies;
if (ap->pflags & ATA_PFLAG_EH_IN_PROGRESS &&
link->eh_context.unloaded_mask & (1 << dev->devno) &&
time_after(dev->unpark_deadline, jiffies))
msecs = jiffies_to_msecs(dev->unpark_deadline - jiffies);
time_after(dev->unpark_deadline, now))
msecs = jiffies_to_msecs(dev->unpark_deadline - now);
else
msecs = 0;