1 files changed, 116 insertions, 0 deletions

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");
+}