[SCSI] zfcp: fix: problem in send_els_handler when D_ID assignment changes

From: Maxim Shchetynin <maxim@de.ibm.com>

Fixes a bug in zfcp_send_els_handler.  If D_ID assignments for ports
are changing between initiation of one ELS request and its completion
the wrong port might be accessed in the completion for that ELS
request. Thus a pointer to the port has to be passed for ELS requests
to identify the port structure if required.

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

3 files changed, 16 insertions, 25 deletions

diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 08369b9dad68..37982058e4d9 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -751,6 +751,7 @@ typedef void (*zfcp_send_els_handler_t)(unsigned long);
 /**
  * struct zfcp_send_els - used to pass parameters to function zfcp_fsf_send_els
  * @adapter: adapter where request is sent from
+ * @port: port where ELS is destinated (port reference count has to be increased)
  * @d_id: destiniation id of port where request is sent to
  * @req: scatter-gather list for request
  * @resp: scatter-gather list for response
@@ -765,6 +766,7 @@ typedef void (*zfcp_send_els_handler_t)(unsigned long);
  */
 struct zfcp_send_els {
         struct zfcp_adapter *adapter;
+        struct zfcp_port *port;
         fc_id_t d_id;
         struct scatterlist *req;
         struct scatterlist *resp;
diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 60ba1ba112d6..41c67e1ec4f7 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -35,7 +35,7 @@
 
 #include "zfcp_ext.h"
 
-static int zfcp_erp_adisc(struct zfcp_adapter *, fc_id_t);
+static int zfcp_erp_adisc(struct zfcp_port *);
 static void zfcp_erp_adisc_handler(unsigned long);
 
 static int zfcp_erp_adapter_reopen_internal(struct zfcp_adapter *, int);
@@ -295,12 +295,12 @@ zfcp_erp_unit_shutdown(struct zfcp_unit *unit, int clear_mask)
 
 /**
  * zfcp_erp_adisc - send ADISC ELS command
- * @adapter: adapter structure
- * @d_id: d_id of port where ADISC is sent to
+ * @port: port structure
  */
 int
-zfcp_erp_adisc(struct zfcp_adapter *adapter, fc_id_t d_id)
+zfcp_erp_adisc(struct zfcp_port *port)
 {
+        struct zfcp_adapter *adapter = port->adapter;
         struct zfcp_send_els *send_els;
         struct zfcp_ls_adisc *adisc;
         void *address = NULL;
@@ -332,7 +332,8 @@ zfcp_erp_adisc(struct zfcp_adapter *adapter, fc_id_t d_id)
         send_els->req_count = send_els->resp_count = 1;
 
         send_els->adapter = adapter;
-        send_els->d_id = d_id;
+        send_els->port = port;
+        send_els->d_id = port->d_id;
         send_els->handler = zfcp_erp_adisc_handler;
         send_els->handler_data = (unsigned long) send_els;
 
@@ -350,7 +351,7 @@ zfcp_erp_adisc(struct zfcp_adapter *adapter, fc_id_t d_id)
         ZFCP_LOG_INFO("ADISC request from s_id 0x%08x to d_id 0x%08x "
                       "(wwpn=0x%016Lx, wwnn=0x%016Lx, "
                       "hard_nport_id=0x%08x, nport_id=0x%08x)\n",
-                      adapter->s_id, d_id, (wwn_t) adisc->wwpn,
+                      adapter->s_id, send_els->d_id, (wwn_t) adisc->wwpn,
                       (wwn_t) adisc->wwnn, adisc->hard_nport_id,
                       adisc->nport_id);
 
@@ -367,7 +368,7 @@ zfcp_erp_adisc(struct zfcp_adapter *adapter, fc_id_t d_id)
         retval = zfcp_fsf_send_els(send_els);
         if (retval != 0) {
                 ZFCP_LOG_NORMAL("error: initiation of Send ELS failed for port "
-                                "0x%08x on adapter %s\n", d_id,
+                                "0x%08x on adapter %s\n", send_els->d_id,
                                 zfcp_get_busid_by_adapter(adapter));
                 del_timer(send_els->timer);
                 goto freemem;
@@ -411,14 +412,9 @@ zfcp_erp_adisc_handler(unsigned long data)
         del_timer(send_els->timer);
 
         adapter = send_els->adapter;
+        port = send_els->port;
         d_id = send_els->d_id;
 
-        read_lock(&zfcp_data.config_lock);
-        port = zfcp_get_port_by_did(send_els->adapter, send_els->d_id);
-        read_unlock(&zfcp_data.config_lock);
-
-        BUG_ON(port == NULL);
-
         /* request rejected or timed out */
         if (send_els->status != 0) {
                 ZFCP_LOG_NORMAL("ELS request rejected/timed out, "
@@ -482,7 +478,7 @@ zfcp_test_link(struct zfcp_port *port)
         int retval;
 
         zfcp_port_get(port);
-        retval = zfcp_erp_adisc(port->adapter, port->d_id);
+        retval = zfcp_erp_adisc(port);
         if (retval != 0) {
                 zfcp_port_put(port);
                 ZFCP_LOG_NORMAL("reopen needed for port 0x%016Lx "
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index bf66fc6d8a97..21a6d7633475 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -1771,8 +1771,8 @@ zfcp_fsf_send_els(struct zfcp_send_els *els)
 static int zfcp_fsf_send_els_handler(struct zfcp_fsf_req *fsf_req)
 {
         struct zfcp_adapter *adapter;
-        fc_id_t d_id;
         struct zfcp_port *port;
+        fc_id_t d_id;
         struct fsf_qtcb_header *header;
         struct fsf_qtcb_bottom_support *bottom;
         struct zfcp_send_els *send_els;
@@ -1781,6 +1781,7 @@ static int zfcp_fsf_send_els_handler(struct zfcp_fsf_req *fsf_req)
 
         send_els = fsf_req->data.send_els;
         adapter = send_els->adapter;
+        port = send_els->port;
         d_id = send_els->d_id;
         header = &fsf_req->qtcb->header;
         bottom = &fsf_req->qtcb->bottom.support;
@@ -1817,13 +1818,8 @@ static int zfcp_fsf_send_els_handler(struct zfcp_fsf_req *fsf_req)
                 switch (header->fsf_status_qual.word[0]){
                 case FSF_SQ_INVOKE_LINK_TEST_PROCEDURE:
                         debug_text_event(adapter->erp_dbf, 1, "fsf_sq_ltest");
-                        if (send_els->ls_code != ZFCP_LS_ADISC) {
-                                read_lock(&zfcp_data.config_lock);
-                                port = zfcp_get_port_by_did(adapter, d_id);
-                                if (port)
-                                        zfcp_test_link(port);
-                                read_unlock(&zfcp_data.config_lock);
-                        }
+                        if (port && (send_els->ls_code != ZFCP_LS_ADISC))
+                                zfcp_test_link(port);
                         fsf_req->status |= ZFCP_STATUS_FSFREQ_ERROR;
                         break;
                 case FSF_SQ_ULP_DEPENDENT_ERP_REQUIRED:
@@ -1913,11 +1909,8 @@ static int zfcp_fsf_send_els_handler(struct zfcp_fsf_req *fsf_req)
                         }
                 }
                 debug_text_event(adapter->erp_dbf, 1, "fsf_s_access");
-                read_lock(&zfcp_data.config_lock);
-                port = zfcp_get_port_by_did(adapter, d_id);
                 if (port != NULL)
                         zfcp_erp_port_access_denied(port);
-                read_unlock(&zfcp_data.config_lock);
                 fsf_req->status |= ZFCP_STATUS_FSFREQ_ERROR;
                 break;