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authorHannes Reinecke <hare@suse.de>2008-07-17 17:49:02 -0700
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-07-26 15:14:53 -0400
commitae11b1b36da726a8a93409b896704edc6b4f3402 (patch)
tree737e3602cb426c87f64ad26ccbfc12ce707d7b9e /drivers/scsi/device_handler/scsi_dh.c
parent057ea7c9683c3d684128cced796f03c179ecf1c2 (diff)
[SCSI] scsi_dh: attach to hardware handler from dm-mpath
multipath keeps a separate device table which may be more current than the built-in one. So we should make sure to always call ->attach whenever a multipath map with hardware handler is instantiated. And we should call ->detach on removal, too. [sekharan: update as per comments from agk] Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/scsi/device_handler/scsi_dh.c')
-rw-r--r--drivers/scsi/device_handler/scsi_dh.c64
1 files changed, 64 insertions, 0 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index e90df9dd3e6..a9159681ff2 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -369,6 +369,70 @@ int scsi_dh_handler_exist(const char *name)
}
EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
+/*
+ * scsi_dh_handler_attach - Attach device handler
+ * @sdev - sdev the handler should be attached to
+ * @name - name of the handler to attach
+ */
+int scsi_dh_attach(struct request_queue *q, const char *name)
+{
+ unsigned long flags;
+ struct scsi_device *sdev;
+ struct scsi_device_handler *scsi_dh;
+ int err = 0;
+
+ scsi_dh = get_device_handler(name);
+ if (!scsi_dh)
+ return -EINVAL;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ sdev = q->queuedata;
+ if (!sdev || !get_device(&sdev->sdev_gendev))
+ err = -ENODEV;
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ if (!err) {
+ err = scsi_dh_handler_attach(sdev, scsi_dh);
+
+ put_device(&sdev->sdev_gendev);
+ }
+ return err;
+}
+EXPORT_SYMBOL_GPL(scsi_dh_attach);
+
+/*
+ * scsi_dh_handler_detach - Detach device handler
+ * @sdev - sdev the handler should be detached from
+ *
+ * This function will detach the device handler only
+ * if the sdev is not part of the internal list, ie
+ * if it has been attached manually.
+ */
+void scsi_dh_detach(struct request_queue *q)
+{
+ unsigned long flags;
+ struct scsi_device *sdev;
+ struct scsi_device_handler *scsi_dh = NULL;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ sdev = q->queuedata;
+ if (!sdev || !get_device(&sdev->sdev_gendev))
+ sdev = NULL;
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ if (!sdev)
+ return;
+
+ if (sdev->scsi_dh_data) {
+ /* if sdev is not on internal list, detach */
+ scsi_dh = sdev->scsi_dh_data->scsi_dh;
+ if (!device_handler_match(scsi_dh, sdev))
+ scsi_dh_handler_detach(sdev, scsi_dh);
+ }
+ put_device(&sdev->sdev_gendev);
+}
+EXPORT_SYMBOL_GPL(scsi_dh_detach);
+
static struct notifier_block scsi_dh_nb = {
.notifier_call = scsi_dh_notifier
};