[SCSI] fix our current target reap infrastructure
This patch eliminates the reap_ref and replaces it with a proper kref.
On last put of this kref, the target is removed from visibility in
sysfs. The final call to scsi_target_reap() for the device is done from
__scsi_remove_device() and only if the device was made visible. This
ensures that the target disappears as soon as the last device is gone
rather than waiting until final release of the device (which is often
too long).
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org # delay backport by 2 months for field testing
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 9117d0b..665acbf 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -383,17 +383,14 @@
{
struct scsi_device *sdev;
struct device *parent;
- struct scsi_target *starget;
struct list_head *this, *tmp;
unsigned long flags;
sdev = container_of(work, struct scsi_device, ew.work);
parent = sdev->sdev_gendev.parent;
- starget = to_scsi_target(parent);
spin_lock_irqsave(sdev->host->host_lock, flags);
- starget->reap_ref++;
list_del(&sdev->siblings);
list_del(&sdev->same_target_siblings);
list_del(&sdev->starved_entry);
@@ -413,8 +410,6 @@
/* NULL queue means the device can't be used */
sdev->request_queue = NULL;
- scsi_target_reap(scsi_target(sdev));
-
kfree(sdev->inquiry);
kfree(sdev);
@@ -1071,6 +1066,13 @@
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(dev);
+ /*
+ * Paired with the kref_get() in scsi_sysfs_initialize(). We have
+ * remoed sysfs visibility from the device, so make the target
+ * invisible if this was the last device underneath it.
+ */
+ scsi_target_reap(scsi_target(sdev));
+
put_device(dev);
}
@@ -1133,7 +1135,7 @@
continue;
if (starget->dev.parent == dev || &starget->dev == dev) {
/* assuming new targets arrive at the end */
- starget->reap_ref++;
+ kref_get(&starget->reap_ref);
spin_unlock_irqrestore(shost->host_lock, flags);
if (last)
scsi_target_reap(last);
@@ -1217,6 +1219,12 @@
list_add_tail(&sdev->same_target_siblings, &starget->devices);
list_add_tail(&sdev->siblings, &shost->__devices);
spin_unlock_irqrestore(shost->host_lock, flags);
+ /*
+ * device can now only be removed via __scsi_remove_device() so hold
+ * the target. Target will be held in CREATED state until something
+ * beneath it becomes visible (in which case it moves to RUNNING)
+ */
+ kref_get(&starget->reap_ref);
}
int scsi_is_sdev_device(const struct device *dev)