[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, 14 insertions, 14 deletions

diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index fb218dd9d934..24e16ec331d9 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -446,37 +446,37 @@ int
 zfcp_qdio_reqid_check(struct zfcp_adapter *adapter, void *sbale_addr)
 {
         struct zfcp_fsf_req *fsf_req;
-        int retval = 0;
 
         /* invalid (per convention used in this driver) */
         if (unlikely(!sbale_addr)) {
                 ZFCP_LOG_NORMAL("bug: invalid reqid\n");
-                retval = -EINVAL;
-                goto out;
+                return -EINVAL;
         }
 
         /* valid request id and thus (hopefully :) valid fsf_req address */
         fsf_req = (struct zfcp_fsf_req *) sbale_addr;
 
+        /* serialize with zfcp_fsf_req_dismiss_all */
+        spin_lock(&adapter->fsf_req_list_lock);
+        if (list_empty(&adapter->fsf_req_list_head)) {
+                spin_unlock(&adapter->fsf_req_list_lock);
+                return 0;
+        }
+        list_del(&fsf_req->list);
+        atomic_dec(&adapter->fsf_reqs_active);
+        spin_unlock(&adapter->fsf_req_list_lock);
+        
         if (unlikely(adapter != fsf_req->adapter)) {
                 ZFCP_LOG_NORMAL("bug: invalid reqid (fsf_req=%p, "
                                 "fsf_req->adapter=%p, adapter=%p)\n",
                                 fsf_req, fsf_req->adapter, adapter);
-                retval = -EINVAL;
-                goto out;
-        }
-
-        ZFCP_LOG_TRACE("fsf_req at %p, QTCB at %p\n", fsf_req, fsf_req->qtcb);
-        if (likely(fsf_req->qtcb)) {
-                ZFCP_LOG_TRACE("hex dump of QTCB:\n");
-                ZFCP_HEX_DUMP(ZFCP_LOG_LEVEL_TRACE, (char *) fsf_req->qtcb,
-                              sizeof(struct fsf_qtcb));
+                return -EINVAL;
         }
 
         /* finish the FSF request */
         zfcp_fsf_req_complete(fsf_req);
- out:
-        return retval;
+
+        return 0;
 }
 
 /**