From: David Milburn <dmilburn@redhat.com>
Subject: [RHEL-5 PATCH] scsi_tranport_fc: check portstates before invoking 	target scan
Date: Wed, 27 Jun 2007 18:22:33 -0500
Bugzilla: 246023
Message-Id: <20070627232233.GA9461@dhcp-210.hsv.redhat.com>
Changelog: [scsi] scsi_tranport_fc: check portstates before invoking target scan


Before calling scsi_scan_target(), fc_user_scan() needs to check
the portstate, if the rport has already been removed this will
cause scsi_scan_target() to oops. If a device has been removed 
fc_remote_port_delete() changes the portstate to FC_PORTSTATE_BLOCKED
and sets up the devloss timeout handler. If devloss timeout expires,
fc_timeout_deleted_rport() runs and the target is removed, this may
cause fc_user_scan() to scan the already removed target.

Customer was able to consistently reproduce this by pulling fc cable, 
and rescanning the host through sysfs before the devloss timeout 
had expired. They have verified the problem is no longer reproducible
with a 2.6.18-8.el5 kernel built with this patch. 

This fix is currently in James Bottomley's scsi-misc-2.6.git tree:
 
 http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=commitdiff;h=0d2fcd9f9858a34f7056b3b1cb60ce0f883d06b6

 BZ 246023 / IT 118144

Please ack or comment.

Thanks,
David

--- linux-2.6.18.i686/drivers/scsi/scsi_transport_fc.c.scan
+++ linux-2.6.18.i686/drivers/scsi/scsi_transport_fc.c
@@ -1452,6 +1452,9 @@ static int fc_user_scan(struct Scsi_Host
 		if (rport->scsi_target_id == -1)
 			continue;
 
+		if (rport->port_state != FC_PORTSTATE_ONLINE)
+			continue;
+
 		if ((channel == SCAN_WILD_CARD || channel == rport->channel) &&
 		    (id == SCAN_WILD_CARD || id == rport->scsi_target_id)) {
 			scsi_scan_target(&rport->dev, rport->channel,