[SCSI] zfcp: Fix deadlock when adding invalid LUN

When adding an invalid LUN, there is a deadlock between the add
via scsi_scan_target and the slave_destroy handler: The handler
waits for the scan to complete, but for an invalid unit,
scsi_scan_target directly calls the slave_destroy handler.

Fix the deadlock by removing the wait in the slave_destroy
handler, it was not necessary anyway.

Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

4 files changed, 0 insertions, 10 deletions

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 00118499018b..874b55ed00a3 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -844,8 +844,6 @@ zfcp_unit_enqueue(struct zfcp_port *port, fcp_lun_t fcp_lun)
         unit->sysfs_device.release = zfcp_sysfs_unit_release;
         dev_set_drvdata(&unit->sysfs_device, unit);
 
-        init_waitqueue_head(&unit->scsi_scan_wq);
-
         /* mark unit unusable as long as sysfs registration is not complete */
         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
 
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 3d2d2dc0d6f8..294d0792e82b 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -983,10 +983,6 @@ struct zfcp_unit {
         struct scsi_device     *device;        /* scsi device struct pointer */
         struct zfcp_erp_action erp_action;     /* pending error recovery */
         atomic_t               erp_counter;
-        wait_queue_head_t      scsi_scan_wq;   /* can be used to wait until
-                                                  all scsi_scan_target
-                                                  requests have been
-                                                  completed. */
 };
 
 /* FSF request */
diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 9c6ea9962cd2..67d74ed0f25c 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -1609,7 +1609,6 @@ static void zfcp_erp_scsi_scan(struct work_struct *work)
         scsi_scan_target(&rport->dev, 0, rport->scsi_target_id,
                          unit->scsi_lun, 0);
         atomic_clear_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
-        wake_up(&unit->scsi_scan_wq);
         zfcp_unit_put(unit);
         kfree(p);
 }
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index c6b6295395b0..3298fd35000c 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -180,9 +180,6 @@ static void zfcp_scsi_slave_destroy(struct scsi_device *sdpnt)
 
         if (unit) {
                 zfcp_erp_wait(unit->port->adapter);
-                wait_event(unit->scsi_scan_wq,
-                           atomic_test_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING,
-                                            &unit->status) == 0);
                 atomic_clear_mask(ZFCP_STATUS_UNIT_REGISTERED, &unit->status);
                 sdpnt->hostdata = NULL;
                 unit->device = NULL;