[PATCH 4.6 098/100] scsi: Add intermediate STARGET_REMOVE state to scsi_target_state

Greg Kroah-Hartman
2016-05-30T21:13:37Z

From: Johannes Thumshirn <jthumshirn@suse.de>

commit f05795d3d771f30a7bdc3a138bf714b06d42aa95 upstream.

Add intermediate STARGET_REMOVE state to scsi_target_state to avoid
running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE
state is only valid in the path from scsi_remove_target() to
scsi_target_destroy() indicating this target is going to be removed.

This re-fixes the problem introduced in commits bc3f02a795d3 ("[SCSI]
scsi_remove_target: fix softlockup regression on hot remove") and
40998193560d ("scsi: restart list search after unlock in
scsi_remove_target") in a more comprehensive way.

[mkp: Included James' fix for scsi_target_destroy()]

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38
Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: James Bottomley <jejb@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/scsi_scan.c | 1 +
drivers/scsi/scsi_sysfs.c | 2 ++
include/scsi/scsi_device.h | 1 +
3 files changed, 4 insertions(+)

--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -316,6 +316,7 @@ static void scsi_target_destroy(struct s
struct Scsi_Host *shost = dev_to_shost(dev->parent);
unsigned long flags;

+ BUG_ON(starget->state == STARGET_DEL);
starget->state = STARGET_DEL;
transport_destroy_device(dev);
spin_lock_irqsave(shost->host_lock, flags);
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1373,11 +1373,13 @@ restart:
spin_lock_irqsave(shost->host_lock, flags);
list_for_each_entry(starget, &shost->__targets, siblings) {
if (starget->state == STARGET_DEL ||
+ starget->state == STARGET_REMOVE ||
starget == last_target)
continue;
if (starget->dev.parent == dev || &starget->dev == dev) {
kref_get(&starget->reap_ref);
last_target = starget;
+ starget->state = STARGET_REMOVE;
spin_unlock_irqrestore(shost->host_lock, flags);
__scsi_remove_target(starget);
scsi_target_reap(starget);
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -242,6 +242,7 @@ scmd_printk(const char *, const struct s
enum scsi_target_state {
STARGET_CREATED = 1,
STARGET_RUNNING,
+ STARGET_REMOVE,
STARGET_DEL,
};