[SCSI] libfc: do not log off rports before or after discovery

When receiving an RSCN, do not log off all rports.  This is
extremely disruptive.  If, after the GPN_FT response, some
rports haven't been listed, delete them.

Add field disc_id to structs fc_rport_priv and fc_disc.
disc_id is an arbitrary serial number used to identify the
rports found by the latest discovery.  This eliminates the need
to go through the rport list when restarting discovery.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

diff --git a/drivers/scsi/libfc/fc_disc.c b/drivers/scsi/libfc/fc_disc.c
index f6762a5..ddf4944 100644 (file)
--- a/drivers/scsi/libfc/fc_disc.c
+++ b/drivers/scsi/libfc/fc_disc.c
@@ -221,17 +221,19 @@ static void fc_disc_recv_req(struct fc_seq *sp, struct fc_frame *fp,
  */
 static void fc_disc_restart(struct fc_disc *disc)
 {
-       struct fc_rport_priv *rdata, *next;
-       struct fc_lport *lport = disc->lport;
-
        FC_DISC_DBG(disc, "Restarting discovery\n");
 
-       list_for_each_entry_safe(rdata, next, &disc->rports, peers)
-               lport->tt.rport_logoff(rdata);
-
        disc->requested = 1;
-       if (!disc->pending)
-               fc_disc_gpn_ft_req(disc);
+       if (disc->pending)
+               return;
+
+       /*
+        * Advance disc_id.  This is an arbitrary non-zero number that will
+        * match the value in the fc_rport_priv after discovery for all
+        * freshly-discovered remote ports.  Avoid wrapping to zero.
+        */
+       disc->disc_id = (disc->disc_id + 2) | 1;
+       fc_disc_gpn_ft_req(disc);
 }
 
 /**
@@ -278,6 +280,7 @@ static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
                }
                kref_put(&rdata->kref, rdata->local_port->tt.rport_destroy);
        } else {
+               disc->disc_id = (disc->disc_id + 2) | 1;
                fc_disc_gpn_ft_req(disc);       /* get ports by FC-4 type */
        }
 
@@ -345,13 +348,30 @@ static int fc_disc_new_target(struct fc_disc *disc,
 static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event)
 {
        struct fc_lport *lport = disc->lport;
+       struct fc_rport_priv *rdata;
 
        FC_DISC_DBG(disc, "Discovery complete\n");
 
-       if (disc->requested)
-               fc_disc_gpn_ft_req(disc);
-       else
-               disc->pending = 0;
+       disc->pending = 0;
+       if (disc->requested) {
+               fc_disc_restart(disc);
+               return;
+       }
+
+       /*
+        * Go through all remote ports.  If they were found in the latest
+        * discovery, reverify or log them in.  Otherwise, log them out.
+        * Skip ports which were never discovered.  These are the dNS port
+        * and ports which were created by PLOGI.
+        */
+       list_for_each_entry(rdata, &disc->rports, peers) {
+               if (!rdata->disc_id)
+                       continue;
+               if (rdata->disc_id == disc->disc_id)
+                       lport->tt.rport_login(rdata);
+               else
+                       lport->tt.rport_logoff(rdata);
+       }
 
        mutex_unlock(&disc->disc_mutex);
        disc->disc_callback(lport, event);
@@ -496,7 +516,7 @@ static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len)
                    ids.port_name != lport->wwpn) {
                        rdata = lport->tt.rport_create(lport, &ids);
                        if (rdata)
-                               lport->tt.rport_login(rdata);
+                               rdata->disc_id = disc->disc_id;
                        else
                                printk(KERN_WARNING "libfc: Failed to allocate "
                                       "memory for the newly discovered port "
@@ -640,6 +660,7 @@ static void fc_disc_single(struct fc_disc *disc, struct fc_disc_port *dp)
 
        rdata = lport->tt.rport_create(lport, &dp->ids);
        if (rdata) {
+               rdata->disc_id = disc->disc_id;
                kfree(dp);
                lport->tt.rport_login(rdata);
        }

diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h
index 093b043..517dce5 100644 (file)
--- a/include/scsi/libfc.h
+++ b/include/scsi/libfc.h
@@ -202,6 +202,7 @@ struct fc_rport_libfc_priv {
  * @ids: remote port identifiers and roles
  * @flags: REC and RETRY supported flags
  * @max_seq: maximum number of concurrent sequences
+ * @disc_id: discovery identifier
  * @maxframe_size: maximum frame size
  * @retries: retry count in current state
  * @e_d_tov: error detect timeout value (in msec)
@@ -218,6 +219,7 @@ struct fc_rport_priv {
        struct fc_rport_identifiers ids;
        u16                        flags;
        u16                        max_seq;
+       u16                        disc_id;
        u16                        maxframe_size;
        unsigned int               retries;
        unsigned int               e_d_tov;
@@ -678,6 +680,7 @@ struct fc_disc {
        unsigned char           requested;
        unsigned short          seq_count;
        unsigned char           buf_len;
+       u16                     disc_id;
 
        void (*disc_callback)(struct fc_lport *,
                              enum fc_disc_event);