Commit 643eb2d9 authored by James Bottomley's avatar James Bottomley
Browse files

[SCSI] rework scsi_target allocation 



The current target allocation code registeres each possible target
with sysfs; it will be deleted again if no useable LUN on this target
was found. This results in a string of 'target add/target remove' uevents.

Based on a patch by Hannes Reinecke <hare@suse.de> this patch reworks
the target allocation code so that only uevents for existing targets
are sent. The sysfs registration is split off from the existing
scsi_target_alloc() into a in a new scsi_add_target() function, which
should be called whenever an existing target is found. Only then a
uevent is sent, so we'll be generating events for existing targets
only.

Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent f7120a4f

drivers/scsi/scsi_scan.c

+34 −38
Original line number Diff line number Diff line
@@ -322,6 +322,21 @@ out: 
	return NULL;

}



static void scsi_target_destroy(struct scsi_target *starget)

{

	struct device *dev = &starget->dev;

	struct Scsi_Host *shost = dev_to_shost(dev->parent);

	unsigned long flags;



	transport_destroy_device(dev);

	spin_lock_irqsave(shost->host_lock, flags);

	if (shost->hostt->target_destroy)

		shost->hostt->target_destroy(starget);

	list_del_init(&starget->siblings);

	spin_unlock_irqrestore(shost->host_lock, flags);

	put_device(dev);

}



static void scsi_target_dev_release(struct device *dev)

{

	struct device *parent = dev->parent;
@@ -406,7 +421,7 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, 
	starget->channel = channel;

	INIT_LIST_HEAD(&starget->siblings);

	INIT_LIST_HEAD(&starget->devices);

	starget->state = STARGET_RUNNING;

	starget->state = STARGET_CREATED;

	starget->scsi_level = SCSI_2;

 retry:

	spin_lock_irqsave(shost->host_lock, flags);
@@ -419,18 +434,6 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, 
	spin_unlock_irqrestore(shost->host_lock, flags);

	/* allocate and add */

	transport_setup_device(dev);

	error = device_add(dev);

	if (error) {

		dev_err(dev, "target device_add failed, error %d\n", error);

		spin_lock_irqsave(shost->host_lock, flags);

		list_del_init(&starget->siblings);

		spin_unlock_irqrestore(shost->host_lock, flags);

		transport_destroy_device(dev);

		put_device(parent);

		kfree(starget);

		return NULL;

	}

	transport_add_device(dev);

	if (shost->hostt->target_alloc) {

		error = shost->hostt->target_alloc(starget);
@@ -438,9 +441,7 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, 
			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);

			/* don't want scsi_target_reap to do the final

			 * put because it will be under the host lock */

			get_device(dev);

			scsi_target_reap(starget);

			put_device(dev);

			scsi_target_destroy(starget);

			return NULL;

		}

	}
@@ -467,18 +468,10 @@ static void scsi_target_reap_usercontext(struct work_struct *work) 
{

	struct scsi_target *starget =

		container_of(work, struct scsi_target, ew.work);

	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);

	unsigned long flags;



	transport_remove_device(&starget->dev);

	device_del(&starget->dev);

	transport_destroy_device(&starget->dev);

	spin_lock_irqsave(shost->host_lock, flags);

	if (shost->hostt->target_destroy)

		shost->hostt->target_destroy(starget);

	list_del_init(&starget->siblings);

	spin_unlock_irqrestore(shost->host_lock, flags);

	put_device(&starget->dev);

	scsi_target_destroy(starget);

}



/**
@@ -493,21 +486,25 @@ void scsi_target_reap(struct scsi_target *starget) 
{

	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);

	unsigned long flags;

	enum scsi_target_state state;

	int empty;



	spin_lock_irqsave(shost->host_lock, flags);

	state = starget->state;

	empty = --starget->reap_ref == 0 &&

		list_empty(&starget->devices) ? 1 : 0;

	spin_unlock_irqrestore(shost->host_lock, flags);



	if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {

		BUG_ON(starget->state == STARGET_DEL);

	if (!empty)

		return;



	BUG_ON(state == STARGET_DEL);

	starget->state = STARGET_DEL;

		spin_unlock_irqrestore(shost->host_lock, flags);

	if (state == STARGET_CREATED)

		scsi_target_destroy(starget);

	else

		execute_in_process_context(scsi_target_reap_usercontext,

					   &starget->ew);

		return;



	}

	spin_unlock_irqrestore(shost->host_lock, flags);



	return;

}



/**
@@ -1056,6 +1053,7 @@ static int scsi_probe_and_add_lun(struct scsi_target *starget, 
					scsi_inq_str(vend, result, 8, 16),

					scsi_inq_str(mod, result, 16, 32));

			});



		}



		res = SCSI_SCAN_TARGET_PRESENT;
@@ -1497,7 +1495,6 @@ struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel, 
	if (scsi_host_scan_allowed(shost))

		scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);

	mutex_unlock(&shost->scan_mutex);

	transport_configure_device(&starget->dev);

	scsi_target_reap(starget);

	put_device(&starget->dev);
@@ -1578,7 +1575,6 @@ static void __scsi_scan_target(struct device *parent, unsigned int channel, 
 out_reap:

	/* now determine if the target has any children at all

	 * and if not, nuke it */

	transport_configure_device(&starget->dev);

	scsi_target_reap(starget);



	put_device(&starget->dev);

drivers/scsi/scsi_sysfs.c

+27 −0
Original line number Diff line number Diff line
@@ -809,6 +809,27 @@ sdev_store_queue_type_rw(struct device *dev, struct device_attribute *attr, 
	return count;

}



static int scsi_target_add(struct scsi_target *starget)

{

	int error;



	if (starget->state != STARGET_CREATED)

		return 0;



	error = device_add(&starget->dev);

	if (error) {

		dev_err(&starget->dev, "target device_add failed, error %d\n", error);

		get_device(&starget->dev);

		scsi_target_reap(starget);

		put_device(&starget->dev);

		return error;

	}

	transport_add_device(&starget->dev);

	starget->state = STARGET_RUNNING;



	return 0;

}



static struct device_attribute sdev_attr_queue_type_rw =

	__ATTR(queue_type, S_IRUGO | S_IWUSR, show_queue_type_field,

	       sdev_store_queue_type_rw);
@@ -824,10 +845,16 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev) 
{

	int error, i;

	struct request_queue *rq = sdev->request_queue;

	struct scsi_target *starget = sdev->sdev_target;



	if ((error = scsi_device_set_state(sdev, SDEV_RUNNING)) != 0)

		return error;



	error = scsi_target_add(starget);

	if (error)

		return error;



	transport_configure_device(&starget->dev);

	error = device_add(&sdev->sdev_gendev);

	if (error) {

		put_device(sdev->sdev_gendev.parent);

include/scsi/scsi_device.h

+2 −1
Original line number Diff line number Diff line
@@ -181,7 +181,8 @@ struct scsi_device { 
	sdev_printk(prefix, (scmd)->device, fmt, ##a)



enum scsi_target_state {

	STARGET_RUNNING = 1,

	STARGET_CREATED = 1,

	STARGET_RUNNING,

	STARGET_DEL,

};

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