[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>

1 files changed, 34 insertions, 13 deletions

diff --git a/drivers/scsi/libfc/fc_disc.c b/drivers/scsi/libfc/fc_disc.c
index f6762a52147d..ddf494424ff4 100644
--- 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);
         }