libata: perform port detach in EH

ata_port_detach() first made sure EH saw ATA_PFLAG_UNLOADING and then
assumed EH context belongs to it and performed detach operation
itself.  However, UNLOADING doesn't disable all of EH and this could
lead to problems including triggering WARN_ON()'s in EH path.

This patch makes port detach behave more like other EH actions such
that ata_port_detach() requests EH to detach and waits for completion.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 4 insertions, 19 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 1ecc3cb0b722..837fb60a6dcc 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6107,8 +6107,6 @@ int ata_host_activate(struct ata_host *host, int irq,
 static void ata_port_detach(struct ata_port *ap)
 {
         unsigned long flags;
-        struct ata_link *link;
-        struct ata_device *dev;
 
         if (!ap->ops->error_handler)
                 goto skip_eh;
@@ -6116,28 +6114,15 @@ static void ata_port_detach(struct ata_port *ap)
         /* tell EH we're leaving & flush EH */
         spin_lock_irqsave(ap->lock, flags);
         ap->pflags |= ATA_PFLAG_UNLOADING;
+        ata_port_schedule_eh(ap);
         spin_unlock_irqrestore(ap->lock, flags);
 
+        /* wait till EH commits suicide */
         ata_port_wait_eh(ap);
 
-        /* EH is now guaranteed to see UNLOADING - EH context belongs
-         * to us.  Restore SControl and disable all existing devices.
-         */
-        ata_for_each_link(link, ap, PMP_FIRST) {
-                sata_scr_write(link, SCR_CONTROL, link->saved_scontrol & 0xff0);
-                ata_for_each_dev(dev, link, ALL)
-                        ata_dev_disable(dev);
-        }
-
-        /* Final freeze & EH.  All in-flight commands are aborted.  EH
-         * will be skipped and retrials will be terminated with bad
-         * target.
-         */
-        spin_lock_irqsave(ap->lock, flags);
-        ata_port_freeze(ap);    /* won't be thawed */
-        spin_unlock_irqrestore(ap->lock, flags);
+        /* it better be dead now */
+        WARN_ON(!(ap->pflags & ATA_PFLAG_UNLOADED));
 
-        ata_port_wait_eh(ap);
         cancel_rearming_delayed_work(&ap->hotplug_task);
 
  skip_eh: