Looks good to me.
On Tue, 2008-05-20 at 16:05 +0200, Hannes Reinecke wrote:
> 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>
> ---
> drivers/md/dm-mpath.c | 13 ++++++
> drivers/scsi/device_handler/scsi_dh.c | 74 +++++++++++++++++++++++++++++++++
> include/scsi/scsi_dh.h | 2 +
> 3 files changed, 89 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index e8f704a..bd2bcf4 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -147,9 +147,12 @@ static struct priority_group *alloc_priority_group(void)
> static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
> {
> struct pgpath *pgpath, *tmp;
> + struct multipath *m = (struct multipath *) 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 arg_set *as, struct path_selector *ps,
> {
> int r;
> struct pgpath *p;
> + struct multipath *m = (struct multipath *) ti->private;
>
> /* we need at least a path arg */
> if (as->argc < 1) {
> @@ -564,6 +568,15 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
> 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 b80fae7..a9404b5 100644
> --- a/drivers/scsi/device_handler/scsi_dh.c
> +++ b/drivers/scsi/device_handler/scsi_dh.c
> @@ -362,6 +362,80 @@ 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;
> + int i, found = 0;
> +
> + 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) {
> + scsi_dh = sdev->scsi_dh_data->scsi_dh;
> + for(i = 0; scsi_dh->devlist[i].vendor; i++) {
> + if (!strncmp(sdev->vendor, scsi_dh->devlist[i].vendor,
> + strlen(scsi_dh->devlist[i].vendor)) &&
> + !strncmp(sdev->model, scsi_dh->devlist[i].model,
> + strlen(scsi_dh->devlist[i].model))) {
> + found = 1;
> + break;
> + }
> + }
> + /* sdev not on internal list, detach */
> + if (!found)
> + scsi_dh_handler_detach(sdev);
> + }
> + put_device(&sdev->sdev_gendev);
> +}
> +EXPORT_SYMBOL_GPL(scsi_dh_detach);
> +
> static struct notifier_block scsi_dh_nb = {
> .notifier_call = scsi_dh_notifier
> };
> diff --git a/include/scsi/scsi_dh.h b/include/scsi/scsi_dh.h
> index 5d05ac0..8032e51 100644
> --- a/include/scsi/scsi_dh.h
> +++ b/include/scsi/scsi_dh.h
> @@ -59,3 +59,5 @@ enum {
>
> 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 *q);
--
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