Starting multipath on a cciss device will cause a kernel
warning to be triggered. Problem is that we're using the
->queuedata field of the request_queue to dereference the
scsi device; however, for other (non-SCSI) devices this
points to a totally different structure.
So we should rather be using accessors here to make
sure ->queuedata points to a valid sdev.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 0119b81..bc96ca6 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -441,7 +441,7 @@ int scsi_dh_set_params(struct request_queue *q, const char *params)
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
+ sdev = scsi_device_from_queue(q);
if (sdev && sdev->scsi_dh_data)
scsi_dh = sdev->scsi_dh_data->scsi_dh;
if (scsi_dh && scsi_dh->set_params && get_device(&sdev->sdev_gendev))
@@ -484,7 +484,7 @@ int scsi_dh_attach(struct request_queue *q, const char *name)
return -EINVAL;
spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
+ sdev = scsi_device_from_queue(q);
if (!sdev || !get_device(&sdev->sdev_gendev))
err = -ENODEV;
spin_unlock_irqrestore(q->queue_lock, flags);
@@ -512,7 +512,7 @@ void scsi_dh_detach(struct request_queue *q)
struct scsi_device_handler *scsi_dh = NULL;
spin_lock_irqsave(q->queue_lock, flags);
- sdev = q->queuedata;
+ sdev = scsi_device_from_queue(q);
if (!sdev || !get_device(&sdev->sdev_gendev))
sdev = NULL;
spin_unlock_irqrestore(q->queue_lock, flags);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index fc3f168..a96fe54 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1614,6 +1614,24 @@ out:
spin_lock_irq(q->queue_lock);
}
+/**
+ * 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->request_fn == scsi_request_fn)
+ sdev = q->queuedata;
+
+ return sdev;
+}
+EXPORT_SYMBOL_GPL(scsi_device_from_queue);
+
u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
{
struct device *host_dev;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index d371c3c..6712446 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -301,6 +301,7 @@ extern void starget_for_each_device(struct scsi_target *, void *,
extern void __starget_for_each_device(struct scsi_target *, void *,
void (*fn)(struct scsi_device *,
void *));
+extern struct scsi_device *scsi_device_from_queue(struct request_queue *);
/* only exposed to implement shost_for_each_device */
extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,
--
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