[PATCH] libata-hp: implement warmplug

Implement warmplug.  User-initiated unplug can be detected by
hostt->slave_destroy() and plug by transportt->user_scan().  This
patch only implements the two callbacks.  The next function will hook
them.

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

2 files changed, 90 insertions, 0 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 8df8ecc51a78..c61cfc742388 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5942,6 +5942,7 @@ EXPORT_SYMBOL_GPL(ata_port_queue_task);
 EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
 EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);
 EXPORT_SYMBOL_GPL(ata_scsi_slave_config);
+EXPORT_SYMBOL_GPL(ata_scsi_slave_destroy);
 EXPORT_SYMBOL_GPL(ata_scsi_change_queue_depth);
 EXPORT_SYMBOL_GPL(ata_scsi_release);
 EXPORT_SYMBOL_GPL(ata_host_intr);
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 12563998d97c..7c1ac58c430a 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -57,6 +57,8 @@ static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
                                         const struct scsi_device *scsidev);
 static struct ata_device * ata_scsi_find_dev(struct ata_port *ap,
                                             const struct scsi_device *scsidev);
+static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
+                              unsigned int id, unsigned int lun);
 
 
 #define RW_RECOVERY_MPAGE 0x1
@@ -727,6 +729,40 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
 }
 
 /**
+ *      ata_scsi_slave_destroy - SCSI device is about to be destroyed
+ *      @sdev: SCSI device to be destroyed
+ *
+ *      @sdev is about to be destroyed for hot/warm unplugging.  If
+ *      this unplugging was initiated by libata as indicated by NULL
+ *      dev->sdev, this function doesn't have to do anything.
+ *      Otherwise, SCSI layer initiated warm-unplug is in progress.
+ *      Clear dev->sdev, schedule the device for ATA detach and invoke
+ *      EH.
+ *
+ *      LOCKING:
+ *      Defined by SCSI layer.  We don't really care.
+ */
+void ata_scsi_slave_destroy(struct scsi_device *sdev)
+{
+        struct ata_port *ap = ata_shost_to_port(sdev->host);
+        unsigned long flags;
+        struct ata_device *dev;
+
+        if (!ap->ops->error_handler)
+                return;
+
+        spin_lock_irqsave(&ap->host_set->lock, flags);
+        dev = __ata_scsi_find_dev(ap, sdev);
+        if (dev && dev->sdev) {
+                /* SCSI device already in CANCEL state, no need to offline it */
+                dev->sdev = NULL;
+                dev->flags |= ATA_DFLAG_DETACH;
+                ata_port_schedule_eh(ap);
+        }
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+}
+
+/**
  *      ata_scsi_change_queue_depth - SCSI callback for queue depth config
  *      @sdev: SCSI device to configure queue depth for
  *      @queue_depth: new queue depth
@@ -2902,3 +2938,56 @@ void ata_scsi_hotplug(void *data)
 
         DPRINTK("EXIT\n");
 }
+
+/**
+ *      ata_scsi_user_scan - indication for user-initiated bus scan
+ *      @shost: SCSI host to scan
+ *      @channel: Channel to scan
+ *      @id: ID to scan
+ *      @lun: LUN to scan
+ *
+ *      This function is called when user explicitly requests bus
+ *      scan.  Set probe pending flag and invoke EH.
+ *
+ *      LOCKING:
+ *      SCSI layer (we don't care)
+ *
+ *      RETURNS:
+ *      Zero.
+ */
+static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
+                              unsigned int id, unsigned int lun)
+{
+        struct ata_port *ap = ata_shost_to_port(shost);
+        unsigned long flags;
+        int rc = 0;
+
+        if (!ap->ops->error_handler)
+                return -EOPNOTSUPP;
+
+        if ((channel != SCAN_WILD_CARD && channel != 0) ||
+            (lun != SCAN_WILD_CARD && lun != 0))
+                return -EINVAL;
+
+        spin_lock_irqsave(&ap->host_set->lock, flags);
+
+        if (id == SCAN_WILD_CARD) {
+                ap->eh_info.probe_mask |= (1 << ATA_MAX_DEVICES) - 1;
+                ap->eh_info.action |= ATA_EH_SOFTRESET;
+        } else {
+                struct ata_device *dev = ata_find_dev(ap, id);
+
+                if (dev) {
+                        ap->eh_info.probe_mask |= 1 << dev->devno;
+                        ap->eh_info.action |= ATA_EH_SOFTRESET;
+                } else
+                        rc = -EINVAL;
+        }
+
+        if (rc == 0)
+                ata_port_schedule_eh(ap);
+
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+        return rc;
+}