[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>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index fea966d..71dd65a 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -147,9 +147,12 @@
static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
{
struct pgpath *pgpath, *tmp;
+ struct multipath *m = ti->private;
list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
list_del(&pgpath->list);
+ if (m->hw_handler_name)
+ scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev));
dm_put_device(ti, pgpath->path.dev);
free_pgpath(pgpath);
}
@@ -548,6 +551,7 @@
{
int r;
struct pgpath *p;
+ struct multipath *m = ti->private;
/* we need at least a path arg */
if (as->argc < 1) {
@@ -566,6 +570,15 @@
goto bad;
}
+ if (m->hw_handler_name) {
+ r = scsi_dh_attach(bdev_get_queue(p->path.dev->bdev),
+ m->hw_handler_name);
+ if (r < 0) {
+ dm_put_device(ti, p->path.dev);
+ goto bad;
+ }
+ }
+
r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
if (r) {
dm_put_device(ti, p->path.dev);
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index e90df9d..a915968 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -369,6 +369,70 @@
}
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
};