[PATCH 42/64] libfc: do not log off rports before or after discovery

Robert Love
2009-08-25T21:02:10Z

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>
---

drivers/scsi/libfc/fc_disc.c | 47 ++++++++++++++++++++++++++++++------------
include/scsi/libfc.h | 3 +++
2 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/drivers/scsi/libfc/fc_disc.c b/drivers/scsi/libfc/fc_disc.c
index f6762a5..ddf4944 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);
}
diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h
index 093b043..517dce5 100644
--- 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);