On 02/16/2017 04:07 PM, Hannes Reinecke wrote:
> The device handler needs to check if a given queue belongs to
> a scsi device; only then does it make sense to attach a device
> handler.
>
> Signed-off-by: Hannes Reinecke <hare@xxxxxxxx>
> ---
> drivers/scsi/scsi_dh.c | 22 ++++------------------
> drivers/scsi/scsi_lib.c | 24 ++++++++++++++++++++++++
> include/scsi/scsi_device.h | 1 +
> 3 files changed, 29 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c
> index b8d3b97..84addee 100644
> --- a/drivers/scsi/scsi_dh.c
> +++ b/drivers/scsi/scsi_dh.c
> @@ -219,20 +219,6 @@ int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
> }
> EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
>
> -static struct scsi_device *get_sdev_from_queue(struct request_queue *q)
> -{
> - struct scsi_device *sdev;
> - unsigned long flags;
> -
> - 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);
> -
> - return sdev;
> -}
> -
> /*
> * scsi_dh_activate - activate the path associated with the scsi_device
> * corresponding to the given request queue.
> @@ -251,7 +237,7 @@ int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
> struct scsi_device *sdev;
> int err = SCSI_DH_NOSYS;
>
> - sdev = get_sdev_from_queue(q);
> + sdev = scsi_device_from_queue(q);
> if (!sdev) {
> if (fn)
> fn(data, err);
> @@ -298,7 +284,7 @@ int scsi_dh_set_params(struct request_queue *q, const char *params)
> struct scsi_device *sdev;
> int err = -SCSI_DH_NOSYS;
>
> - sdev = get_sdev_from_queue(q);
> + sdev = scsi_device_from_queue(q);
> if (!sdev)
> return err;
>
> @@ -321,7 +307,7 @@ int scsi_dh_attach(struct request_queue *q, const char *name)
> struct scsi_device_handler *scsi_dh;
> int err = 0;
>
> - sdev = get_sdev_from_queue(q);
> + sdev = scsi_device_from_queue(q);
> if (!sdev)
> return -ENODEV;
>
> @@ -359,7 +345,7 @@ const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
> struct scsi_device *sdev;
> const char *handler_name = NULL;
>
> - sdev = get_sdev_from_queue(q);
> + sdev = scsi_device_from_queue(q);
> if (!sdev)
> return NULL;
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 9d6aed5..9c732d3 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -2145,6 +2145,30 @@ void scsi_mq_destroy_tags(struct Scsi_Host *shost)
> blk_mq_free_tag_set(&shost->tag_set);
> }
>
> +/**
> + * scsi_device_from_queue - return sdev associated with a request_queue
> + * @q: The request queue to return the sdev from
> + *
> + * Return the sdev associated with a request queue or NULL if the
> + * request_queue does not reference a SCSI device.
> + */
> +struct scsi_device *scsi_device_from_queue(struct request_queue *q)
> +{
> + struct scsi_device *sdev = NULL;
> + unsigned long flags;
> +
> + spin_lock_irqsave(q->queue_lock, flags);
> + if (q->mq_ops) {
> + if (q->mq_ops == &scsi_mq_ops)
> + sdev = q->queuedata;
> + } else if (q->request_fn == scsi_request_fn)
> + sdev = q->queuedata;
> + spin_unlock_irqrestore(q->queue_lock, flags);
> +
> + return sdev;
> +}
> +EXPORT_SYMBOL_GPL(scsi_device_from_queue);
> +
> /*
> * Function: scsi_block_requests()
> *
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index 8990e58..be41c76 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -315,6 +315,7 @@ extern int scsi_add_device(struct Scsi_Host *host, uint channel,
> extern int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh);
> void scsi_attach_vpd(struct scsi_device *sdev);
>
> +extern struct scsi_device *scsi_device_from_queue(struct request_queue *q);
> extern int scsi_device_get(struct scsi_device *);
> extern void scsi_device_put(struct scsi_device *);
> extern struct scsi_device *scsi_device_lookup(struct Scsi_Host *,
>
fsck. Forgot the 'get_device' thingie.
Will be reposting shortly.
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
