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Commit 27c888f0 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

scsi_dh: get module reference outside of device handler 



We need to grab a reference to the module before calling the attach
routines to avoid a small race vs module removal.  It also cleans up
the code significantly as a side effect.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
parent 0b9c0844

drivers/scsi/device_handler/scsi_dh.c

+22 −9
Original line number Diff line number Diff line
@@ -102,23 +102,36 @@ static int scsi_dh_handler_attach(struct scsi_device *sdev, 


	if (sdev->scsi_dh_data) {

		if (sdev->scsi_dh_data->scsi_dh != scsi_dh)

			err = -EBUSY;

		else

			return -EBUSY;



		kref_get(&sdev->scsi_dh_data->kref);

	} else if (scsi_dh->attach) {

		return 0;

	}



	if (scsi_dh->attach) {

		if (!try_module_get(scsi_dh->module))

			return -EINVAL;



		err = scsi_dh->attach(sdev);

		if (!err) {

		if (err) {

			module_put(scsi_dh->module);

			return err;

		}



		kref_init(&sdev->scsi_dh_data->kref);

		sdev->scsi_dh_data->sdev = sdev;

	}

	}

	return err;

}



static void __detach_handler (struct kref *kref)

{

	struct scsi_dh_data *scsi_dh_data = container_of(kref, struct scsi_dh_data, kref);

	scsi_dh_data->scsi_dh->detach(scsi_dh_data->sdev);

	struct scsi_dh_data *scsi_dh_data =

		container_of(kref, struct scsi_dh_data, kref);

	struct scsi_device_handler *scsi_dh = scsi_dh_data->scsi_dh;



	scsi_dh->detach(scsi_dh_data->sdev);

	module_put(scsi_dh->module);

}



/*

drivers/scsi/device_handler/scsi_dh_alua.c

+0 −4
Original line number Diff line number Diff line
@@ -873,9 +873,6 @@ static int alua_bus_attach(struct scsi_device *sdev) 
	if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))

		goto failed;



	if (!try_module_get(THIS_MODULE))

		goto failed;



	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);

	sdev->scsi_dh_data = scsi_dh_data;

	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@@ -908,7 +905,6 @@ static void alua_bus_detach(struct scsi_device *sdev) 
	if (h->buff && h->inq != h->buff)

		kfree(h->buff);

	kfree(scsi_dh_data);

	module_put(THIS_MODULE);

	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);

}

drivers/scsi/device_handler/scsi_dh_emc.c

+0 −4
Original line number Diff line number Diff line
@@ -692,9 +692,6 @@ static int clariion_bus_attach(struct scsi_device *sdev) 
	if (err != SCSI_DH_OK)

		goto failed;



	if (!try_module_get(THIS_MODULE))

		goto failed;



	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);

	sdev->scsi_dh_data = scsi_dh_data;

	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@@ -728,7 +725,6 @@ static void clariion_bus_detach(struct scsi_device *sdev) 
		    CLARIION_NAME);



	kfree(scsi_dh_data);

	module_put(THIS_MODULE);

}



static int __init clariion_init(void)

drivers/scsi/device_handler/scsi_dh_hp_sw.c

+0 −4
Original line number Diff line number Diff line
@@ -377,9 +377,6 @@ static int hp_sw_bus_attach(struct scsi_device *sdev) 
	if (ret != SCSI_DH_OK || h->path_state == HP_SW_PATH_UNINITIALIZED)

		goto failed;



	if (!try_module_get(THIS_MODULE))

		goto failed;



	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);

	sdev->scsi_dh_data = scsi_dh_data;

	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@@ -406,7 +403,6 @@ static void hp_sw_bus_detach( struct scsi_device *sdev ) 
	scsi_dh_data = sdev->scsi_dh_data;

	sdev->scsi_dh_data = NULL;

	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

	module_put(THIS_MODULE);



	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", HP_SW_NAME);

drivers/scsi/device_handler/scsi_dh_rdac.c

+0 −4
Original line number Diff line number Diff line
@@ -878,9 +878,6 @@ static int rdac_bus_attach(struct scsi_device *sdev) 
	if (err != SCSI_DH_OK)

		goto clean_ctlr;



	if (!try_module_get(THIS_MODULE))

		goto clean_ctlr;



	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);

	sdev->scsi_dh_data = scsi_dh_data;

	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@@ -924,7 +921,6 @@ static void rdac_bus_detach( struct scsi_device *sdev ) 
		kref_put(&h->ctlr->kref, release_controller);

	spin_unlock(&list_lock);

	kfree(scsi_dh_data);

	module_put(THIS_MODULE);

	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME);

}