From: David Milburn <dmilburn@redhat.com>
Date: Thu, 18 Sep 2008 12:39:01 -0500
Subject: [ata] libata: rmmod pata_sil680 hangs
Message-id: 20080918173901.GA21887@dhcp-210.hsv.redhat.com
O-Subject: [RHEL5.3 PATCH] libata: rmmod pata_sil680 hangs
Bugzilla: 462743
RH-Acked-by: Jeff Garzik <jgarzik@redhat.com>

Dell reported they were unable to successfully unload
the pata_sil680 module on a RHEL5 test kernel built
with the sata update. I have been able to reproduce
in house using the -115.el5 kernel. The problem is due
to the RHEL5.3 sata update pulling in an upstream
change in ata_port_detach which results in spinning
in cancel_rearming_delayed_workqueue if there is no
pending timer. This patch reverts back to the RHEL5.2
code and fixes BZ 462743, Dell confirmed this has fixed
their unload problem and I have verified a patched
-115.el5 kernel. Dell's testing results were reported
in previous post.

http://post-office.corp.redhat.com/archives/rhkernel-list/2008-September/msg00676.html

Please review and ACK.

Thanks,
David

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index c2d1cca..ca76707 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5958,7 +5958,10 @@ static void ata_port_detach(struct ata_port *ap)
 	spin_unlock_irqrestore(ap->lock, flags);
 
 	ata_port_wait_eh(ap);
-	cancel_rearming_delayed_work(&ap->hotplug_task);
+
+	flush_workqueue(ata_aux_wq);
+	if (!cancel_delayed_work(&ap->hotplug_task))
+		flush_workqueue(ata_aux_wq);
 
  skip_eh:
 	/* remove the associated SCSI host */