[RESEND PATCH v2 2/2] scsi: Add intermediate STARGET_REMOVE state to scsi_target_state

Johannes Thumshirn
2016-03-30T07:09:53Z

Add intermediate STARGET_REMOVE state to scsi_target_state to avoid running
into the BUG_ON() in scsi_target_reap().

This intermediate state is only valid in the path from scsi_remove_target() to
scsi_target_destroy() indicating this target is going to be removed.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38
Cc: stable@vger.kernel.org
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
---

Changes from v1:
* The state transition from STARGET_CREATED to STARGET_DEL is legitimate,
so don't BUG() on it. Found by the 0-Day Bot.

drivers/scsi/scsi_scan.c | 2 ++
drivers/scsi/scsi_sysfs.c | 4 +++-
include/scsi/scsi_device.h | 1 +
3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 6a82066..63b8bca 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -315,6 +315,8 @@ static void scsi_target_destroy(struct scsi_target *starget)
struct Scsi_Host *shost = dev_to_shost(dev->parent);
unsigned long flags;

+ BUG_ON(starget->state != STARGET_REMOVE &&
+ starget->state != STARGET_CREATED);
starget->state = STARGET_DEL;
transport_destroy_device(dev);
spin_lock_irqsave(shost->host_lock, flags);
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 4f18a85..9e5f893 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1278,10 +1278,12 @@ void scsi_remove_target(struct device *dev)
restart:
spin_lock_irqsave(shost->host_lock, flags);
list_for_each_entry(starget, &shost->__targets, siblings) {
- if (starget->state == STARGET_DEL)
+ if (starget->state == STARGET_DEL ||
+ starget->state == STARGET_REMOVE)
continue;
if (starget->dev.parent == dev || &starget->dev == dev) {
kref_get(&starget->reap_ref);
+ starget->state = STARGET_REMOVE;
spin_unlock_irqrestore(shost->host_lock, flags);
__scsi_remove_target(starget);
scsi_target_reap(starget);
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index f63a167..2bffaa6 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -240,6 +240,7 @@ scmd_printk(const char *, const struct scsi_cmnd *, const char *, ...);
enum scsi_target_state {
STARGET_CREATED = 1,
STARGET_RUNNING,
+ STARGET_REMOVE,
STARGET_DEL,
};

--
1.8.5.6