5 files changed, 124 insertions, 2 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index c965eea3b3d4..8df8ecc51a78 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5370,6 +5370,7 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host,
         ap->msg_enable = ATA_MSG_DRV;
 
         INIT_WORK(&ap->port_task, NULL, NULL);
+        INIT_WORK(&ap->hotplug_task, ata_scsi_hotplug, ap);
         INIT_LIST_HEAD(&ap->eh_done_q);
         init_waitqueue_head(&ap->eh_wait_q);
 
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index b53e2e7db498..733dfa532977 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -287,9 +287,13 @@ void ata_scsi_error(struct Scsi_Host *host)
         /* clean up */
         spin_lock_irqsave(hs_lock, flags);
 
+        if (ap->flags & ATA_FLAG_SCSI_HOTPLUG)
+                queue_work(ata_aux_wq, &ap->hotplug_task);
+
         if (ap->flags & ATA_FLAG_RECOVERED)
                 ata_port_printk(ap, KERN_INFO, "EH complete\n");
-        ap->flags &= ~ATA_FLAG_RECOVERED;
+
+        ap->flags &= ~(ATA_FLAG_SCSI_HOTPLUG | ATA_FLAG_RECOVERED);
 
         /* tell wait_eh that we're done */
         ap->flags &= ~ATA_FLAG_EH_IN_PROGRESS;
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 3dc6188af0e8..12563998d97c 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -2786,3 +2786,119 @@ int ata_scsi_offline_dev(struct ata_device *dev)
         }
         return 0;
 }
+
+/**
+ *      ata_scsi_remove_dev - remove attached SCSI device
+ *      @dev: ATA device to remove attached SCSI device for
+ *
+ *      This function is called from ata_eh_scsi_hotplug() and
+ *      responsible for removing the SCSI device attached to @dev.
+ *
+ *      LOCKING:
+ *      Kernel thread context (may sleep).
+ */
+static void ata_scsi_remove_dev(struct ata_device *dev)
+{
+        struct ata_port *ap = dev->ap;
+        struct scsi_device *sdev;
+        unsigned long flags;
+
+        /* Alas, we need to grab scan_mutex to ensure SCSI device
+         * state doesn't change underneath us and thus
+         * scsi_device_get() always succeeds.  The mutex locking can
+         * be removed if there is __scsi_device_get() interface which
+         * increments reference counts regardless of device state.
+         */
+        mutex_lock(&ap->host->scan_mutex);
+        spin_lock_irqsave(&ap->host_set->lock, flags);
+
+        /* clearing dev->sdev is protected by host_set lock */
+        sdev = dev->sdev;
+        dev->sdev = NULL;
+
+        if (sdev) {
+                /* If user initiated unplug races with us, sdev can go
+                 * away underneath us after the host_set lock and
+                 * scan_mutex are released.  Hold onto it.
+                 */
+                if (scsi_device_get(sdev) == 0) {
+                        /* The following ensures the attached sdev is
+                         * offline on return from ata_scsi_offline_dev()
+                         * regardless it wins or loses the race
+                         * against this function.
+                         */
+                        scsi_device_set_state(sdev, SDEV_OFFLINE);
+                } else {
+                        WARN_ON(1);
+                        sdev = NULL;
+                }
+        }
+
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+        mutex_unlock(&ap->host->scan_mutex);
+
+        if (sdev) {
+                ata_dev_printk(dev, KERN_INFO, "detaching (SCSI %s)\n",
+                               sdev->sdev_gendev.bus_id);
+
+                scsi_remove_device(sdev);
+                scsi_device_put(sdev);
+        }
+}
+
+/**
+ *      ata_scsi_hotplug - SCSI part of hotplug
+ *      @data: Pointer to ATA port to perform SCSI hotplug on
+ *
+ *      Perform SCSI part of hotplug.  It's executed from a separate
+ *      workqueue after EH completes.  This is necessary because SCSI
+ *      hot plugging requires working EH and hot unplugging is
+ *      synchronized with hot plugging with a mutex.
+ *
+ *      LOCKING:
+ *      Kernel thread context (may sleep).
+ */
+void ata_scsi_hotplug(void *data)
+{
+        struct ata_port *ap = data;
+        int i;
+
+        if (ap->flags & ATA_FLAG_UNLOADING) {
+                DPRINTK("ENTER/EXIT - unloading\n");
+                return;
+        }
+
+        DPRINTK("ENTER\n");
+
+        /* unplug detached devices */
+        for (i = 0; i < ATA_MAX_DEVICES; i++) {
+                struct ata_device *dev = &ap->device[i];
+                unsigned long flags;
+
+                if (!(dev->flags & ATA_DFLAG_DETACHED))
+                        continue;
+
+                spin_lock_irqsave(&ap->host_set->lock, flags);
+                dev->flags &= ~ATA_DFLAG_DETACHED;
+                spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+                ata_scsi_remove_dev(dev);
+        }
+
+        /* scan for new ones */
+        ata_scsi_scan_host(ap);
+
+        /* If we scanned while EH was in progress, scan would have
+         * failed silently.  Requeue if there are enabled but
+         * unattached devices.
+         */
+        for (i = 0; i < ATA_MAX_DEVICES; i++) {
+                struct ata_device *dev = &ap->device[i];
+                if (ata_dev_enabled(dev) && !dev->sdev) {
+                        queue_delayed_work(ata_aux_wq, &ap->hotplug_task, HZ);
+                        break;
+                }
+        }
+
+        DPRINTK("EXIT\n");
+}
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index e38759fdc183..0586b0cd73fd 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -76,6 +76,7 @@ extern struct scsi_transport_template ata_scsi_transport_template;
 
 extern void ata_scsi_scan_host(struct ata_port *ap);
 extern int ata_scsi_offline_dev(struct ata_device *dev);
+extern void ata_scsi_hotplug(void *data);
 extern unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
                                unsigned int buflen);
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 56971943d261..407115624d9f 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -521,7 +521,7 @@ struct ata_port {
         struct ata_host_set     *host_set;
         struct device           *dev;
 
-        struct work_struct      port_task;
+        struct work_struct      port_task, hotplug_task;
 
         unsigned int            hsm_task_state;