[SCSI] zfcp: fix bug during adapter shutdown

Fixes a race between zfcp_fsf_req_dismiss_all and
zfcp_qdio_reqid_check. During adapter shutdown it occurred that a
request was cleaned up twice. First during its normal
completion. Second when dismiss_all was called.  The fix is to
serialize access to fsf request list between zfcp_fsf_req_dismiss_all
and zfcp_qdio_reqid_check and delete a fsf request from the list if
its completion is triggered.  (Additionally a rwlock was replaced by a
spinlock and fsf_req_cleanup was eliminated.)

Signed-off-by: Andreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 41c67e1ec4f7..6d73891eec9e 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -891,7 +891,7 @@ zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *erp_action)
 
         if (erp_action->fsf_req) {
                 /* take lock to ensure that request is not being deleted meanwhile */
-                write_lock(&adapter->fsf_req_list_lock);
+                spin_lock(&adapter->fsf_req_list_lock);
                 /* check whether fsf req does still exist */
                 list_for_each_entry(fsf_req, &adapter->fsf_req_list_head, list)
                     if (fsf_req == erp_action->fsf_req)
@@ -934,7 +934,7 @@ zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *erp_action)
                          */
                         erp_action->fsf_req = NULL;
                 }
-                write_unlock(&adapter->fsf_req_list_lock);
+                spin_unlock(&adapter->fsf_req_list_lock);
         } else
                 debug_text_event(adapter->erp_dbf, 3, "a_ca_noreq");