Here is the modified patch as per Alasdair's comment.
Thanks Alasdair.
chandra
On Fri, 2008-07-18 at 01:08 +0100, Alasdair G Kergon wrote:
> On Thu, Jul 17, 2008 at 04:53:27PM -0700, Chandra Seetharaman wrote:
> > +++ linux-2.6.26-git5/drivers/md/dm-mpath.c
> > @@ -147,9 +147,12 @@ static struct priority_group *alloc_prio
> > static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
> > {
> > struct pgpath *pgpath, *tmp;
> > + struct multipath *m = (struct multipath *) ti->private;
>
> > @@ -546,6 +549,7 @@ static struct pgpath *parse_path(struct
> > {
> > int r;
> > struct pgpath *p;
> > + struct multipath *m = (struct multipath *) ti->private;
>
> FYI We're not writing explicit casts in cases like that in new dm code.
>
> Alasdair
-------------------------------------
Subject: [PATCH 7/8] 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.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx>
---
drivers/md/dm-mpath.c | 13 +++++++
drivers/scsi/device_handler/scsi_dh.c | 64 +++++++++++++++++++++++++++++++++
include/scsi/scsi_dh.h | 2 +
3 files changed, 79 insertions(+), 0 deletions(-)
Index: linux-2.6.26-git5/drivers/md/dm-mpath.c
===================================================================
--- linux-2.6.26-git5.orig/drivers/md/dm-mpath.c
+++ linux-2.6.26-git5/drivers/md/dm-mpath.c
@@ -147,9 +147,12 @@ static struct priority_group *alloc_prio
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);
}
@@ -546,6 +549,7 @@ static struct pgpath *parse_path(struct
{
int r;
struct pgpath *p;
+ struct multipath *m = ti->private;
/* we need at least a path arg */
if (as->argc < 1) {
@@ -564,6 +568,15 @@ static struct pgpath *parse_path(struct
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);
Index: linux-2.6.26-git5/drivers/scsi/device_handler/scsi_dh.c
===================================================================
--- linux-2.6.26-git5.orig/drivers/scsi/device_handler/scsi_dh.c
+++ linux-2.6.26-git5/drivers/scsi/device_handler/scsi_dh.c
@@ -369,6 +369,70 @@ int scsi_dh_handler_exist(const char *na
}
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
};
Index: linux-2.6.26-git5/include/scsi/scsi_dh.h
===================================================================
--- linux-2.6.26-git5.orig/include/scsi/scsi_dh.h
+++ linux-2.6.26-git5/include/scsi/scsi_dh.h
@@ -58,6 +58,8 @@ enum {
#if defined(CONFIG_SCSI_DH) || defined(CONFIG_SCSI_DH_MODULE)
extern int scsi_dh_activate(struct request_queue *);
extern int scsi_dh_handler_exist(const char *);
+extern int scsi_dh_attach(struct request_queue *, const char *);
+extern void scsi_dh_detach(struct request_queue *);
#else
static inline int scsi_dh_activate(struct request_queue *req)
{
@@ -67,4 +69,12 @@ static inline int scsi_dh_handler_exist(
{
return 0;
}
+static inline int scsi_dh_attach(struct request_queue *req, const char *name)
+{
+ return SCSI_DH_NOSYS;
+}
+static inline void scsi_dh_detach(struct request_queue *q)
+{
+ return;
+}
#endif
--
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