firewire: fw-sbp2: don't retry login or reconnect after unplug

If a device is being unplugged while fw-sbp2 had a login or reconnect on
schedule, it would take about half a minute to shut the fw_unit down:

    Jan 27 18:34:54 stein firewire_sbp2: logged in to fw2.0 LUN 0000 (0 retries)
    <unplug>
    Jan 27 18:34:59 stein firewire_sbp2: sbp2_scsi_abort
    Jan 27 18:34:59 stein scsi 25:0:0:0: Device offlined - not ready after error recovery
    Jan 27 18:35:01 stein firewire_sbp2: orb reply timed out, rcode=0x11
    Jan 27 18:35:06 stein firewire_sbp2: orb reply timed out, rcode=0x11
    Jan 27 18:35:12 stein firewire_sbp2: orb reply timed out, rcode=0x11
    Jan 27 18:35:17 stein firewire_sbp2: orb reply timed out, rcode=0x11
    Jan 27 18:35:22 stein firewire_sbp2: orb reply timed out, rcode=0x11
    Jan 27 18:35:27 stein firewire_sbp2: orb reply timed out, rcode=0x11
    Jan 27 18:35:32 stein firewire_sbp2: orb reply timed out, rcode=0x11
    Jan 27 18:35:32 stein firewire_sbp2: failed to login to fw2.0 LUN 0000
    Jan 27 18:35:32 stein firewire_sbp2: released fw2.0

After this patch, typically only a few seconds spent in __scsi_add_device
remain:

    Jan 27 19:05:50 stein firewire_sbp2: logged in to fw2.0 LUN 0000 (0 retries)
    <unplug>
    Jan 27 19:05:56 stein firewire_sbp2: sbp2_scsi_abort
    Jan 27 19:05:56 stein scsi 33:0:0:0: Device offlined - not ready after error recovery
    Jan 27 19:05:56 stein firewire_sbp2: released fw2.0

The benefit of this is less noise in the syslog.  It furthermore avoids
a few wasted CPU cycles and needlessly prolonged lifetime of a few
driver objects.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>

drivers/firewire/fw-sbp2.c

@@ -499,6 +499,9 @@ sbp2_send_management_orb(struct sbp2_logical_unit *lu, int node_id,
 	unsigned int timeout;
 	int retval = -ENOMEM;
 
+	if (function == SBP2_LOGOUT_REQUEST && fw_device_is_shutdown(device))
+		return 0;
+
 	orb = kzalloc(sizeof(*orb), GFP_ATOMIC);
 	if (orb == NULL)
 		return -ENOMEM;
@@ -619,16 +622,13 @@ static void sbp2_release_target(struct kref *kref)
 	struct sbp2_logical_unit *lu, *next;
 	struct Scsi_Host *shost =
 		container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
-	struct fw_device *device = fw_device(tgt->unit->device.parent);
 
 	list_for_each_entry_safe(lu, next, &tgt->lu_list, link) {
 		if (lu->sdev)
 			scsi_remove_device(lu->sdev);
 
-		if (!fw_device_is_shutdown(device))
-			sbp2_send_management_orb(lu, tgt->node_id,
-					lu->generation, SBP2_LOGOUT_REQUEST,
-					lu->login_id, NULL);
+		sbp2_send_management_orb(lu, tgt->node_id, lu->generation,
+				SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
 
 		fw_core_remove_address_handler(&lu->address_handler);
 		list_del(&lu->link);
@@ -673,6 +673,9 @@ static void sbp2_login(struct work_struct *work)
 	struct sbp2_login_response response;
 	int generation, node_id, local_node_id;
 
+	if (fw_device_is_shutdown(device))
+		goto out;
+
 	generation    = device->generation;
 	smp_rmb();    /* node_id must not be older than generation */
 	node_id       = device->node_id;
@@ -944,6 +947,9 @@ static void sbp2_reconnect(struct work_struct *work)
 	struct fw_device *device = fw_device(unit->device.parent);
 	int generation, node_id, local_node_id;
 
+	if (fw_device_is_shutdown(device))
+		goto out;
+
 	generation    = device->generation;
 	smp_rmb();    /* node_id must not be older than generation */
 	node_id       = device->node_id;