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

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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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
This commit is contained in:
Christoph Hellwig 2015-08-27 14:17:00 +02:00 committed by James Bottomley
parent ee14c674e8
commit e959ed9a44
1 changed files with 46 additions and 53 deletions
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99
drivers/scsi/scsi_dh.c
View file

@ -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);
@ -348,21 +358,15 @@ 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;
err = sdev->handler->set_params(sdev, params);
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;
sdev = get_sdev_from_queue(q);
if (!sdev)
return -ENODEV;
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);
if (err)
return err;
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;
}