[PATCH 4.9 062/153] scsi: use scsi_device_from_queue() for scsi_dh

Greg Kroah-Hartman
2017-03-10T11:02:59Z

From: Hannes Reinecke <hare@suse.de>

commit 857de6e00778738dc3d61f75acbac35bdc48e533 upstream.

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.

[mkp: dropped flags]

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/scsi_dh.c | 22 ++++------------------
drivers/scsi/scsi_lib.c | 23 +++++++++++++++++++++++
include/scsi/scsi_device.h | 1 +
3 files changed, 28 insertions(+), 18 deletions(-)

--- a/drivers/scsi/scsi_dh.c
+++ b/drivers/scsi/scsi_dh.c
@@ -219,20 +219,6 @@ int scsi_unregister_device_handler(struc
}
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_queu
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_qu
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
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_nam
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;

--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2127,6 +2127,29 @@ void scsi_mq_destroy_tags(struct Scsi_Ho
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;
+
+ 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;
+ if (!sdev || !get_device(&sdev->sdev_gendev))
+ sdev = NULL;
+
+ return sdev;
+}
+EXPORT_SYMBOL_GPL(scsi_device_from_queue);
+
/*
* Function: scsi_block_requests()
*
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -315,6 +315,7 @@ extern void scsi_remove_device(struct sc
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 *,