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Commit e959ed9a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by James Bottomley
Browse files

scsi_dh: add a common helper to get a scsi_device from a request_queue 



And cleanup the various messy opencoded versions of this.  Note that this
moves the sdev_state checks outside the queue_lock coverage, but as
we don't hold the lock over the activation they are only advisory anyway.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJames Bottomley <JBottomley@Odin.com>
parent ee14c674

drivers/scsi/scsi_dh.c

+46 −53
Original line number Diff line number Diff line
@@ -283,6 +283,20 @@ 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.
@@ -298,41 +312,37 @@ EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); 
 */

int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)

{

	int err = 0;

	unsigned long flags;

	struct scsi_device *sdev;

	struct device *dev = NULL;

	int err = SCSI_DH_NOSYS;



	spin_lock_irqsave(q->queue_lock, flags);

	sdev = q->queuedata;

	sdev = get_sdev_from_queue(q);

	if (!sdev) {

		spin_unlock_irqrestore(q->queue_lock, flags);

		err = SCSI_DH_NOSYS;

		if (fn)

			fn(data, err);

		return err;

	}



	dev = get_device(&sdev->sdev_gendev);

	if (!sdev->handler || !dev ||

	    sdev->sdev_state == SDEV_CANCEL ||

	if (!sdev->handler)

		goto out_fn;

	if (sdev->sdev_state == SDEV_CANCEL ||

	    sdev->sdev_state == SDEV_DEL)

		err = SCSI_DH_NOSYS;

	if (sdev->sdev_state == SDEV_OFFLINE)

		err = SCSI_DH_DEV_OFFLINED;

	spin_unlock_irqrestore(q->queue_lock, flags);

		goto out_fn;



	if (err) {

		if (fn)

			fn(data, err);

		goto out;

	}

	err = SCSI_DH_DEV_OFFLINED;

	if (sdev->sdev_state == SDEV_OFFLINE)

		goto out_fn;



	if (sdev->handler->activate)

		err = sdev->handler->activate(sdev, fn, data);

out:

	put_device(dev);



out_put_device:

	put_device(&sdev->sdev_gendev);

	return err;



out_fn:

	if (fn)

		fn(data, err);

	goto out_put_device;

}

EXPORT_SYMBOL_GPL(scsi_dh_activate);
@@ -348,20 +358,14 @@ EXPORT_SYMBOL_GPL(scsi_dh_activate); 
 */

int scsi_dh_set_params(struct request_queue *q, const char *params)

{

	int err = -SCSI_DH_NOSYS;

	unsigned long flags;

	struct scsi_device *sdev;

	int err = -SCSI_DH_NOSYS;



	spin_lock_irqsave(q->queue_lock, flags);

	sdev = q->queuedata;

	if (sdev->handler &&

	    sdev->handler->set_params &&

	    get_device(&sdev->sdev_gendev))

		err = 0;

	spin_unlock_irqrestore(q->queue_lock, flags);



	if (err)

	sdev = get_sdev_from_queue(q);

	if (!sdev)

		return err;



	if (sdev->handler && sdev->handler->set_params)

		err = sdev->handler->set_params(sdev, params);

	put_device(&sdev->sdev_gendev);

	return err;
@@ -376,23 +380,19 @@ EXPORT_SYMBOL_GPL(scsi_dh_set_params); 
 */

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 = scsi_dh_lookup(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);

	sdev = get_sdev_from_queue(q);

	if (!sdev)

		return -ENODEV;



	if (err)

		return err;

	scsi_dh = scsi_dh_lookup(name);

	if (!scsi_dh) {

		err = -EINVAL;

		goto out_put_device;

	}



	if (sdev->handler) {

		if (sdev->handler != scsi_dh)
@@ -419,22 +419,15 @@ EXPORT_SYMBOL_GPL(scsi_dh_attach); 
 */

const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)

{

	unsigned long flags;

	struct scsi_device *sdev;

	const char *handler_name = 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);



	sdev = get_sdev_from_queue(q);

	if (!sdev)

		return NULL;



	if (sdev->handler)

		handler_name = kstrdup(sdev->handler->name, gfp);



	put_device(&sdev->sdev_gendev);

	return handler_name;

}