[PATCH] libata-hp: update unload-unplug

Update unload unplug - driver unloading / PCI removal.  This is done
by ata_port_detach() which short-circuits EH, disables all devices and
freezes the port.  With this patch, EH and unloading/unplugging are
properly synchronized.

Signed-off-by: Tejun Heo <htejun@gmail.com>

3 files changed, 70 insertions, 15 deletions

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index afb3805f9e95..60f455bf3696 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -1389,21 +1389,17 @@ static void ahci_remove_one (struct pci_dev *pdev)
         struct device *dev = pci_dev_to_dev(pdev);
         struct ata_host_set *host_set = dev_get_drvdata(dev);
         struct ahci_host_priv *hpriv = host_set->private_data;
-        struct ata_port *ap;
         unsigned int i;
         int have_msi;
 
-        for (i = 0; i < host_set->n_ports; i++) {
-                ap = host_set->ports[i];
-
-                scsi_remove_host(ap->host);
-        }
+        for (i = 0; i < host_set->n_ports; i++)
+                ata_port_detach(host_set->ports[i]);
 
         have_msi = hpriv->flags & AHCI_FLAG_MSI;
         free_irq(host_set->irq, host_set);
 
         for (i = 0; i < host_set->n_ports; i++) {
-                ap = host_set->ports[i];
+                struct ata_port *ap = host_set->ports[i];
 
                 ata_scsi_release(ap->host);
                 scsi_host_put(ap->host);
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index a42877e6b865..01f2c59536bc 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5610,6 +5610,63 @@ err_free_ret:
 }
 
 /**
+ *      ata_port_detach - Detach ATA port in prepration of device removal
+ *      @ap: ATA port to be detached
+ *
+ *      Detach all ATA devices and the associated SCSI devices of @ap;
+ *      then, remove the associated SCSI host.  @ap is guaranteed to
+ *      be quiescent on return from this function.
+ *
+ *      LOCKING:
+ *      Kernel thread context (may sleep).
+ */
+void ata_port_detach(struct ata_port *ap)
+{
+        unsigned long flags;
+        int i;
+
+        if (!ap->ops->error_handler)
+                return;
+
+        /* tell EH we're leaving & flush EH */
+        spin_lock_irqsave(&ap->host_set->lock, flags);
+        ap->flags |= ATA_FLAG_UNLOADING;
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+        ata_port_wait_eh(ap);
+
+        /* EH is now guaranteed to see UNLOADING, so no new device
+         * will be attached.  Disable all existing devices.
+         */
+        spin_lock_irqsave(&ap->host_set->lock, flags);
+
+        for (i = 0; i < ATA_MAX_DEVICES; i++)
+                ata_dev_disable(&ap->device[i]);
+
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+        /* 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->host_set->lock, flags);
+        ata_port_freeze(ap);    /* won't be thawed */
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+        ata_port_wait_eh(ap);
+
+        /* Flush hotplug task.  The sequence is similar to
+         * ata_port_flush_task().
+         */
+        flush_workqueue(ata_aux_wq);
+        cancel_delayed_work(&ap->hotplug_task);
+        flush_workqueue(ata_aux_wq);
+
+        /* remove the associated SCSI host */
+        scsi_remove_host(ap->host);
+}
+
+/**
  *      ata_host_set_remove - PCI layer callback for device removal
  *      @host_set: ATA host set that was removed
  *
@@ -5622,18 +5679,15 @@ err_free_ret:
 
 void ata_host_set_remove(struct ata_host_set *host_set)
 {
-        struct ata_port *ap;
         unsigned int i;
 
-        for (i = 0; i < host_set->n_ports; i++) {
-                ap = host_set->ports[i];
-                scsi_remove_host(ap->host);
-        }
+        for (i = 0; i < host_set->n_ports; i++)
+                ata_port_detach(host_set->ports[i]);
 
         free_irq(host_set->irq, host_set);
 
         for (i = 0; i < host_set->n_ports; i++) {
-                ap = host_set->ports[i];
+                struct ata_port *ap = host_set->ports[i];
 
                 ata_scsi_release(ap->host);
 
@@ -5901,6 +5955,7 @@ EXPORT_SYMBOL_GPL(sata_deb_timing_before_fsrst);
 EXPORT_SYMBOL_GPL(ata_std_bios_param);
 EXPORT_SYMBOL_GPL(ata_std_ports);
 EXPORT_SYMBOL_GPL(ata_device_add);
+EXPORT_SYMBOL_GPL(ata_port_detach);
 EXPORT_SYMBOL_GPL(ata_host_set_remove);
 EXPORT_SYMBOL_GPL(ata_sg_init);
 EXPORT_SYMBOL_GPL(ata_sg_init_one);
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index 70c132bef68e..30a83a57a12f 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -46,6 +46,7 @@
 #include "libata.h"
 
 static void __ata_port_freeze(struct ata_port *ap);
+static void ata_eh_finish(struct ata_port *ap);
 
 static void ata_ering_record(struct ata_ering *ering, int is_io,
                              unsigned int err_mask)
@@ -242,8 +243,11 @@ void ata_scsi_error(struct Scsi_Host *host)
 
                 spin_unlock_irqrestore(hs_lock, flags);
 
-                /* invoke EH */
-                ap->ops->error_handler(ap);
+                /* invoke EH.  if unloading, just finish failed qcs */
+                if (!(ap->flags & ATA_FLAG_UNLOADING))
+                        ap->ops->error_handler(ap);
+                else
+                        ata_eh_finish(ap);
 
                 /* Exception might have happend after ->error_handler
                  * recovered the port but before this point.  Repeat