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authorElias Oltmanns <eo@nebensachen.de>2008-11-03 19:01:08 +0900
committerJeff Garzik <jgarzik@redhat.com>2008-11-04 01:08:24 -0500
commita464189de350b050aa8f334bd4cc53ed406e56dd (patch)
treed4acc5c1f65eca5522bbd28ae2702e54a1f8db0a
parent3c324283e6cdb79210cf7975c3e40d3ba3e672b2 (diff)
downloadlinux-a464189de350b050aa8f334bd4cc53ed406e56dd.tar.bz2
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>
-rw-r--r--drivers/ata/libata-scsi.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index bbb30d882f05..3fa75eac135d 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -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;