Hi all,
currently we have this:
struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
uint lun)
{
struct scsi_device *sdev;
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
unsigned long flags;
spin_lock_irqsave(shost->host_lock, flags);
sdev = __scsi_device_lookup_by_target(starget, lun);
if (sdev && scsi_device_get(sdev))
sdev = NULL;
spin_unlock_irqrestore(shost->host_lock, flags);
return sdev;
}
now consider an sdev list with two entries for LUN 0, the first
being in SDEV_DEL and the second being in SDEV_RUNNING.
scsi_device_lookup_by_target will always return NULL here, as
it will never be able to skip past the first (unuseable)
entry. So scsi_report_lun_scan will happily create duplicate
sdevs for LUN 0 and we'll be getting the infamous
sysfs: duplicate filename 'xxxx' can not be created
errors.
What we should be doing here is to restart
__scsi_device_lookup_by_target() if we find an
sdev but cannot use it (ie is in SDEV_DEL).
James, please apply.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
Restart scsi_device_lookup_by_target()
When scsi_device_lookup_by_target() will always return
the first sdev with a matching LUN, regardless of
the state. However, when this sdev is in SDEV_DEL
it's quite possible to have additional sdevs in the
list with the same LUN which are active.
So we should restart __scsi_device_lookup_by_target()
whenever we find an sdev with state SDEV_DEL.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index 62a4618..ac0488b 100644
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -1158,7 +1158,7 @@ static int esp_reconnect(struct esp *esp)
ESP_BUSID);
tp = &esp->target[target];
- dev = __scsi_device_lookup_by_target(tp->starget, lun);
+ dev = __scsi_device_lookup_by_target(tp->starget, NULL, lun);
if (!dev) {
printk(KERN_ERR PFX "esp%d: Reconnect, no lp "
"tgt[%u] lun[%u]\n",
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index f8b79d4..b2c3c61 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -1094,23 +1094,29 @@ EXPORT_SYMBOL(__starget_for_each_device);
/**
* __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
* @starget: SCSI target pointer
+ * @sdev: SCSI device pointer
* @lun: SCSI Logical Unit Number
*
* Description: Looks up the scsi_device with the specified @lun for a given
* @starget. The returned scsi_device does not have an additional
* reference. You must hold the host's host_lock over this call and
- * any access to the returned scsi_device.
+ * any access to the returned scsi_device. If @sdev is not NULL use the
+ * specified @sdev as a starting point after which to start the lookup.
*
* Note: The only reason why drivers should use this is because
* they need to access the device list in irq context. Otherwise you
* really want to use scsi_device_lookup_by_target instead.
**/
struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
+ struct scsi_device *sdev,
uint lun)
{
- struct scsi_device *sdev;
+ if (!sdev)
+ sdev = list_prepare_entry(sdev, &starget->devices,
+ same_target_siblings);
- list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
+ list_for_each_entry_continue(sdev, &starget->devices,
+ same_target_siblings) {
if (sdev->lun ==lun)
return sdev;
}
@@ -1131,14 +1137,15 @@ EXPORT_SYMBOL(__scsi_device_lookup_by_target);
struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
uint lun)
{
- struct scsi_device *sdev;
+ struct scsi_device *sdev = NULL;
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
unsigned long flags;
spin_lock_irqsave(shost->host_lock, flags);
- sdev = __scsi_device_lookup_by_target(starget, lun);
+ restart:
+ sdev = __scsi_device_lookup_by_target(starget, sdev, lun);
if (sdev && scsi_device_get(sdev))
- sdev = NULL;
+ goto restart;
spin_unlock_irqrestore(shost->host_lock, flags);
return sdev;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index bb80937..710f150 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -285,6 +285,7 @@ extern struct scsi_device *__scsi_device_lookup(struct Scsi_Host *,
extern struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *,
uint);
extern struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *,
+ struct scsi_device *,
uint);
extern void starget_for_each_device(struct scsi_target *, void *,
void (*fn)(struct scsi_device *, void *));
